Inventory Based Rating System Pilot
Data Collection and
Implementation Report
December 8, 2015
Authors:
Tim Colling, PhD., PE
John Kiefer, PE
Pete Torola, PE
Department of Civil and
Environmental Engineering
Michigan Technological University
1400 Townsend Drive
Houghton, MI 49931
Table of Contents
Executive Summary ................................................................................................................... 4
1.0
Acknowledgement.......................................................................................................... 5
2.0
Introduction ................................................................................................................... 5
2.1
Limitations of Existing Unpaved Road Assessment Systems................................................ 6
2.2
3.0
Premise of Inventory-Based Rating System ......................................................................... 7
Objective and Scope ....................................................................................................... 8
4.0
Methods......................................................................................................................... 9
4.1
Selection of Data Collection Locations ................................................................................. 9
4.2
Pre-Field Work Training ...................................................................................................... 11
4.3
Data Collection Methodology ............................................................................................ 11
4.3.1
Inventory Based Rating Data Collection ..................................................................... 12
4.3.2
Gravel Thickness Data Collection ............................................................................... 14
4.3.3
Combined PASER and IBR Collection .......................................................................... 14
4.3.4
User Feedback ............................................................................................................ 15
5.0
Results ......................................................................................................................... 15
5.1
Feedback from Users .......................................................................................................... 15
5.2
Data Summaries from Collection ....................................................................................... 15
5.2.1
Antrim County ............................................................................................................ 18
5.2.2
Baraga County ............................................................................................................ 20
5.2.3
Huron County ............................................................................................................. 22
5.2.4
Kalamazoo County ...................................................................................................... 24
5.2.5
Van Buren County....................................................................................................... 25
5.3 Benchmarking Rating Productivity ........................................................................................... 27
5.3.1
Combined PASER/IBR Collection Benchmarking ........................................................ 27
5.3.2
System Wide IBR Collection Estimates ....................................................................... 28
5.4
Repeatability of Measurement .......................................................................................... 29
6.0
Conclusions .................................................................................................................. 32
6.1
Recommendation for Modification of the Original System ............................................... 32
6.1.1
Modifications to the Drainage Adequacy Measurement Rating Guidance ............... 32
6.1.2
Modifications to the Structural Adequacy Measurement Rating Guidance .............. 33
6.1.3
Concerns Over the Intent of Good-Fair-Poor Designations ....................................... 33
6.2
Repeatability/Reliability of the System .............................................................................. 34
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 1
6.3
Recommendation for Implementation (Policy for Collection) ........................................... 34
References ...................................................................................................................................... 36
Appendix A: User Feedback and Comments .............................................................................. 37
Appendix B: Draft TAMC Policy for Collection of Roadway Condition Data on Federal-Aid Eligible
Roads & Streets ....................................................................................................................... 42
Appendix C: Draft Policy for Collection of Roadway Condition Data on (Paved and Unpaved) NonFederal Aid Eligible Roads & Streets ......................................................................................... 46
Appendix C: Training Handout.................................................................................................. 48
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 2
Table of Figures
Figure 1: Qualitative classification of counties based on unpaved road network type. .................... 10
Figure 2: Roadsoft data set for Antrim County showing unpaved roads. .......................................... 12
Figure 3: Laptop Data Collector showing Huron County IBR collection data. .................................... 13
Figure 4: IBR Surface Width data as a percentage of roads rated during the pilot. .......................... 16
Figure 5: IBR Drainage Adequacy data as a percentage of roads rated during the pilot. .................. 16
Figure 6: IBR Structural Adequacy data as a percentage of roads rated during the pilot. ................ 17
Figure 7: Combined IBR number as a percentage of roads rated during the pilot. ........................... 17
Figure 8: Converted 10-point scale IBR numbers collected during the pilot. .................................... 18
Figure 9: Antrim County pilot data collection. ................................................................................... 19
Figure 10: Antrim County unpaved road showing poor Surface Width, poor Drainage Adequacy, and
poor Structural Adequacy. ................................................................................................................. 20
Figure 11: Baraga County pilot data collection. ................................................................................. 21
Figure 12: Thickly vegetated roadsides in Baraga County.................................................................. 22
Figure 13: Huron County pilot data collection. .................................................................................. 23
Figure 14: Huron County unpaved road showing good Surface Width and good Drainage Adequacy.
............................................................................................................................................................ 23
Figure 15: Kalamazoo County pilot data collection............................................................................ 24
Figure 16: Kalamazoo County unpaved road showing fair Surface Width and poor Drainage
Adequacy. ........................................................................................................................................... 25
Figure 17: Van Buren County pilot data collection. ........................................................................... 26
Figure 18: Van Buren County unpaved road with fair Surface Width and fair Drainage Adequacy. . 26
Figure 19: IBR element point difference (rater minus ground truth) ................................................ 30
Figure 20: IBR number difference for all pilot segments and PASER results for paved road segments
as a basis of comparison for data collection repeatability................................................................. 31
Figure 21: Validation of the institutional knowledge on gravel thickness. ........................................ 32
Table of Tables
Table 1: IBR data collection statistics by county. ............................................................................... 27
Table 2: IBR data and joint IBR and PASER data collection statistics. ................................................ 28
Table 3: System wide IBR data collection estimates. ......................................................................... 29
Table 4: U.S. Climatic Region III recommended aggregate base thickness. ....................................... 33
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 3
Executive Summary
To comply with State statutes on reporting conditions of the Michigan public road network, the
Michigan Transportation Asset Management Council (TAMC) has adopted condition assessment
systems for use by local road agencies. The Pavement Surface Evaluation and Rating (PASER)
system for asphalt, concrete and sealcoat roads, and the National Bridge Inventory (NBI) rating
system for public bridges have both proven to be cost-effective network-level metrics for reporting
to the Michigan Legislature, and provides usable data on a local and regional level. The rating
systems for unpaved roads, however, lacked in accuracy and effectiveness. Most of the rating
systems currently in use for unpaved roads are derived from paved road assessment systems,
which focus on surface condition as the primary factor in assessing road quality. Surface quality is a
much less reliable rating factor for unpaved roads because it can change rapidly and is only one
road inventory feature, which includes road width, drainage, and other features.
To meet the need of a condition assessment system for unpaved roads, the Inventory-Based Rating
(IBR) system was created and implemented as a pilot project in five Michigan counties, assessing
roads based on Surface Width, Drainage Adequacy and Structural Adequacy. These inventory
features were selected because of their impact on road users and the significant cost to create and
maintain them. The system defines a baseline condition for each inventory feature, which indicates
a good rating in this good-fair-poor rating system.
The five counties were selected based on classification of their road networks; their selection
depended upon overall function, management and maintenance of unpaved roads. The Center for
Technology & Training (CTT) staff trained those who participated in the pilot data collection and
participants collected data on Surface Width, Drainage Adequacy and Structural Adequacy over
one to two days. The CTT performed a second series of data collection events, which included
gravel thickness measurements at randomly selected locations. The CTT also collected user
feedback and comments on the IBR system were collected from the participants during the study.
The data collected showed the repeatability of the IBR system to be very high, and the data
collectors were ultimately very successful in providing reliable results. The pilot also provided
productivity benchmarking, which can be used to forecast the time commitment for collecting the
IBR system data. The user feedback was very positive and helpful, and modifications to improve the
Drainage Adequacy and Structural Adequacy rating guidance have been implemented. The CTT
recommends an update to the Roadsoft Laptop Data Collector (LDC) for future IBR data collection,
and a plan has been recommended to collect IBR data over one to two years followed by three- to
four-year re-rating cycles and ratings as needed after projects that change the IBR features.
It is recommended is that IBR data be collected and reimbursed on the same cycle as PASER data
Training for the IBR data collection should be required which is consistent with PASER data
collection.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 4
1.0 Acknowledgement
The Michigan Transportation Asset Management Council (TAMC) and Michigan Technological
University wish to acknowledge the contribution of the transportation professionals that assisted in
the data collection necessary for this report and the refinements they suggested in an effort to
develop a new unpaved road rating method that meets the needs of Michigan’s transportation
agencies. Staff assisting in the field collection of data for this report were:
Kevin Arndt – Huron County Road Commission
Megan Arndt – Kalamazoo Area Transportation Study
Ken Barnett – Van Buren County Road Commission
Travis Bartholomew – Road Commission of Kalamazoo County
Bill DeYoung – Road Commission of Kalamazoo County
Craig Ericksen – Van Buren County Road Commission
Bob Fitzgerald – Antrim County Road Commission
Bruce Holdwick – Huron County Road Commission
Joel Hoort – Van Buren County Road Commission
Gautam Mani – Southwest Michigan Planning Commission
Doug Mills, PE – Baraga County Road Commission
Fred Nagler, PE – Kalamazoo Area Transportation Study
Lynne Parker – East Michigan Council of Governments
Mark Piotter, PE – Huron County Road Commission
Linnea Rader – Van Buren County Road Commission
Jeffrey Rautiola, PE – Michigan Department of Transportation
Steve Rouser – Western Upper Peninsula Planning & Development Region
Scott Swanson – Baraga County Road Commission
Burt Thompson, PE – Antrim County Road Commission
2.0 Introduction
The TAMC is charged by State statute with reporting the condition of the Michigan public road
network to the Michigan Legislature [1]. To this end, the TAMC has successfully adopted existing
condition assessment systems for paved roads and bridges in Michigan. The Pavement Surface
Evaluation and Rating (PASER) [2,3,4] system for asphalt, concrete, and sealcoat roads has been
used by road owning agencies in the State of Michigan since the 1990’s and suits the needs of the
TAMC as a cost-effective network-level metric for reporting to the Legislature. PASER data on
paved roads have been collected and reported to the Michigan Legislature by the TAMC since 2002
[1]. Similarly, the TAMC has adopted the use of the National Bridge Inventory (NBI) rating system to
report the condition of public bridges in the State. The TAMC, however, has not identified a
suitable condition assessment system for unpaved roads that meets their requirements of
providing a cost-effective, stable, network-level measure in a beneficial way for local road
managers.
Condition assessment systems can serve two general purposes: providing project-level guidance
that infers a type or class of treatment necessary for a given asset, and providing a network-level
metric to evaluate the overall system performance. The best assessment systems serve both
purposes. Pavement condition assessment systems that provide project-level guidance can be used
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 5
to determine when specific maintenance activity on a specific section of road should be conducted.
The PASER system, for example, was developed so that road owners could infer specific classes of
treatments that would be appropriate based on a road’s current rating [2,3,4]. Condition
assessment systems that provide a network-level measure can be used as a metric to assess the
overall health of the road network. Network-level measures are important for efficient road
management because they provide an easy method for determining the level of investment
necessary to maintain or work toward a condition target. For example, the TAMC uses the
percentage of paved road miles that have a PASER number of 4 or below as its major network-level
metric for the paved road system [1].
2.1
Limitations of Existing Unpaved Road Assessment Systems
Many condition assessment systems exist for unpaved roads with measurement methods ranging
from basic to complicated [5]. However, none of these existing systems have been found to
provide a reliable, stable, network-level assessment that is cost effective to collect on the scale
necessary for the TAMC’s statewide purposes.
Most of the unpaved road condition assessment systems that are widely used evolved from paved
road assessment systems. As a result, they use the extent and severity of surface distresses as their
primary factor in assessing road quality. Focusing on surface distress as a measure of quality works
well for paved roads because surface distresses change slowly and require a significant effort to
repair, making the distresses relatively static over the course of a year [2,3,4]. This slow rate of
change allows a single rating event every one to two years to provide a sufficient level of data for
management purposes on paved roads. However, unlike paved roads, unpaved roads can have
significant changes in surface condition over a matter of days or weeks [6], thus limiting the
effectiveness of surface distress-driven condition assessment systems both at a network- and
project-selection level.
Rapid changes in the surface condition of unpaved roads cause condition data to become quickly
outdated and, therefore, require frequent data collection cycles in order to remain valid for
project-level guidance, making these types of systems difficult to adapt cost-effectively. Similarly,
rating systems based on surface conditions are difficult to apply as a network-level measure since
the condition of any road in the system may be highly variable during the year as distresses appear
and short-term maintenance activity such as grading are completed. Significant surface condition
changes in the network may take place in the span of a single week. This results in a network-level
metric that can vary greatly from week to week depending on when ratings were collected.
Surface condition is a primary factor that impacts use of a paved road by motorists and is directly
related to the life of the most expensive layer of the pavement, which is surfacing, that typically
drives major improvement work in a paved road network. Unpaved roads, however, can have many
other factors that influence their functionality that are not related to surface condition. Unpaved
roads are highly variable in their design, construction, use, and upkeep when compared with paved
roads. Many unpaved roads do not contain basic inventory elements common to most paved
roads, which makes the exclusive focus on surface condition problematic. These inventory items
include sufficient ditches and culverts, minimum lane widths, shoulders, and sufficient structural
gravel to support loads. Differences in inventory elements can adversely influence the use of the
road and may have more of an impact on users than poor surface conditions. For example, road
users may consider potholes or ruts on an unpaved road a secondary inconvenience if the unpaved
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 6
road is only nine-feet wide and the limited surface width will not allow the operation of two-way
vehicle traffic at any significant speed. In this case, surface condition may be irrelevant to users.
Similarly, an unpaved road without proper drainage is likely to perform poorly for any traffic
volume regardless of the current surface condition [6]. Poor unpaved road surface condition does
not always relate to the life of the surfacing layer and more typically may be rectified by low-cost
grading. As such, unpaved road surface condition is not automatically indicative of a loss in value of
the road as is the case with paved roads.
2.2
Premise of Inventory-Based Rating System
The report titled Inventory Based Assessment Systems for Unpaved Roads [7] outlines the
Inventory-Based Rating (IBR) system. This report described the premise behind the selection of
basic road inventory features that influence road users and have a significant cost to create or
maintain. These features are the basic large-scale elements that a “good” quality road possesses.
The IBR system functions by defining a baseline condition for each of the inventory features in the
system. This baseline condition for inventory features used characteristics that are considered
acceptable for the majority of road users with guidance from design standards. The baseline
condition does not imply a mandate to correct roads that do not meet baseline conditions but,
rather, creates a reference to compare with other roads. The baseline condition is, in effect, a zeropoint in the system. Roads are assessed based on how they compare to the baseline condition in
each of the inventory feature categories. Not meeting any of the baseline condition features will
result in a road being rated lower than those that meet all baseline conditions.
Inventory features used in this system (Surface Width, Drainage Adequacy and Structural
Adequacy) do not change rapidly, require a significant construction or maintenance effort to
improve, and are apparent enough to be evaluated from a moving vehicle without the need for fine
measurement. Once initial ratings are established, this system only requires updates when a
construction or rehabilitation activity occurs, or when a lack of maintenance causes loss or
degradation of a road feature. Monitoring inventory features over time at a network level provides
a measure that can track the impact of investments on the unpaved road network.
The three inventory features used by the IBR system are assessed using the following criteria:
Surface Width
Surface width is assessed by estimating the approximate width of the traveled portion of
the road, which includes travel lanes and any shoulder that is suitable for travel.
•
Good – Surface width of 22 feet or greater
•
Fair – Surface width between 16 to 21 feet
•
Poor – Surface width of 15 feet or less
Drainage Adequacy
Drainage adequacy is assessed by determining the presence or absence of a secondary
ditch (high shoulder) that has the capacity to retain surface water and by estimating the
difference in elevation between the ditch flow line or level of standing water in the ditch
and the top of the edge of the shoulder.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 7
•
Good – Two feet or more of difference in elevation between the ditch flow line or any
standing water (whichever is less) and the top edge of the shoulder; no secondary
ditches are present
•
Fair – Between two and 0.5 feet of difference in elevation between the ditch flow line
or any standing water (whichever is less) and the edge of the shoulder, with or without
the presence of secondary ditches; or, two feet or more vertical separation between
the ditch flow line or any standing water (whichever is less) and the top edge of the
shoulder where secondary ditches are present
•
Poor – Less than 0.5 feet of difference in elevation between the ditch flow line or any
standing water (whichever is less) and the edge of the shoulder; secondary ditches may
or may not be present
Structural Adequacy
Structural adequacy is assessed by the presence or lack of structural distresses (rutting or
large potholes) during the previous year that required emergency maintenance to maintain
serviceability. If the data are unknown, the assessment can be conducted using an estimate
of gravel thickness if known. It is not the intent of this inventory feature to require involved
testing or exploration of existing conditions. Ratings are to be made based on local
institutional knowledge.
•
Good – Structural rutting or major (three feet or larger) potholes did not develop
throughout the year and emergency maintenance was not required leaving the road as
serviceable throughout the year (when plowed). Alternately, the road can be assessed
by estimating the thickness of good quality gravel (crushed and dense graded). An
estimated thickness of eight inches or more of good gravel would qualify a road for this
level.
•
Fair –Limited structural rutting and/or some major (three feet or larger) potholes
during the spring or very wet periods. The road is passable throughout the year, but
emergency maintenance grading was necessary to maintain it during the wet periods.
Placement of four inches of good quality gravel would be recommended as a fix.
Alternately, the road can be assessed by determining the gravel thickness is four to
seven inches, thus some additional gravel material could be added.
•
Poor – Structural rutting and/or major (three feet or larger) potholes are apparent
during much of the year. The road is passable throughout the year, but frequent
emergency maintenance is required. Placement of five to eight inches of good quality
gravel would be recommended as a fix. Alternately, the road can be assessed by
determining the gravel thickness is less than four inches, thus significant additional
gravel material should be added.
See Appendix C: Training Handout for further detail on assessment criteria.
3.0 Objective and Scope
The objective of this study was to collect data on various types of unpaved roads under real world
conditions to assess the repeatability and accuracy of the IBR system given the variety of users and
the variety of road networks across the state of Michigan. The study provided benchmarking
information on data collection speeds, identified areas where more guidance on the system was
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 8
necessary, and where the rating system needed to be refined. The pilot project provided an
opportunity to determine training and guidance needs and to get direct feedback from
transportation professionals who will be responsible for collecting and using the data locally. The
data collected for this project provided local agencies and the TAMC with a first-hand look at the
type of information they need to implement full-scale collection and provide a means for assessing
the value of these data. Data collected in this pilot can be used to estimate the scope, cost, and
other planning factors necessary for potential statewide rollout of the IBR collection.
4.0 Methods
4.1
Selection of Data Collection Locations
Unpaved roads in Michigan vary greatly from county to county in how they are used, constructed,
and maintained. The project team defined three general classifications of road networks based on
overall function, management, and maintenance of unpaved roads in each county. The
classifications used were:
Low Volume Terminal Branch Networks
Unpaved roads in Low Volume Terminal Branch Networks were primarily used as the
“ends” of the road system where traffic volumes were low and primarily consist of areas
where the road accessed few properties. In many cases, year-round access or use of the
road is often not necessary. Counties in the Upper Peninsula and northern Lower Michigan
generally fall into this category.
Agricultural Grid Networks
Unpaved roads in Agricultural Grid Networks were primarily used to support agriculture
that is a large part of the local economy by providing regular access to farm fields. These
types of road networks seasonally support higher volumes of traffic and need to support
larger truck loads to meet the needs of users. Generally speaking, access is maintained all
year because these types of networks serve residents and agriculture. Agricultural Grid
Networks typically provided users with a higher amount of mobility and access than Low
Volume Terminal Branch Networks.
Suburban Residential Networks
Unpaved roads in Suburban Residential Networks were primarily used as local access to
rural residential properties located near urban centers. These types of roads provide access
all year to primarily passenger vehicle traffic. These types of road networks were near
urban centers and were primarily located in the population belt between Grand Rapids and
Detroit.
Figure 1 illustrates the project team’s qualitative assessment of Michigan counties into these types
of networks.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 9
Baraga
Antrim
Huron
Van Buren
Low Volume Terminal Branch Networks
Agricultural Grid Networks
Suburban Residential Networks
Kalamazoo
Figure 1: Qualitative classification of counties based on unpaved road network type. Volunteer pilot counties outlined in
bold.
The original goal of the project was to collect a total of 1,000 miles of unpaved road rating data
using the IBR system in at least four counties made up of at least one from each of the three
network classifications spread geographically throughout the state. This selected sample size could
provide enough data to make accurate predictions for statewide data collection rates, check the
validity of the system, and make improvements to the training materials that will be needed for
statewide implementation.
A selection of five counties distributed across each of the three network types were solicited for
cooperation in collecting data for this study. Cooperation in the study was purely voluntary, and
county road commission and regional planning staff participating in the study did so at their own
expense. The following counties volunteered for data collection during this study: Antrim, Baraga,
Kalamazoo, Huron, and Van Buren. Figure 1 illustrates the locations of the volunteer counties.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 10
4.2
Pre-Field Work Training
Engineers from CTT trained agency employees from the five volunteer counties and planning
agency representatives who participated in the pilot data collection prior to doing the actual
ratings of the unpaved roads. The training consisted of a two-hour PowerPoint presentation with
in-class rating exercises and a two-page quick reference handout. All of the training materials used
during the pilot are included in Appendix C. Group rating exercises, which were conducted as part
of the training program, helped to provide experience using the system prior to field rating. The
agencies also received the Inventory Based Assessment Systems for Unpaved Roads report for their
review prior to conducting the training.
4.3
Data Collection Methodology
Three discrete data collection events comprised this pilot. The first set of data collection trips
collected IBR data for each of the five volunteer counties. The IBR data consisting of Surface Width,
Drainage Adequacy, and Structural Adequacy for each roadway segment were graded into one of
three ranges (good, fair, or poor) according to the IBR system as well as rating productivity
measures (see report section 2.2 Premise of Inventory-Based Rating System for more detail on the
criteria used for these ratings). The IBR data collection was completed over the course of one to
two days for each volunteer county. This series of collection events recorded the team consensus
IBR data as well as “blind” IBR data on selected road segments.
The second series of data collection events followed shortly after the completion of the IBR
collection and included collecting gravel thickness measurements at randomly selected locations.
CTT staff returned to each county for half a day to determine the depth of gravel on roads
previously rated using the IBR system. Gravel depth measurements were used to determine the
accuracy of local agency staff knowledge about road structure.
The third data collection event was limited to Baraga County. This collection event gathered both
IBR data for unpaved roads and PASER data for paved roads were collected in a joint effort. These
data were used to determine the relative efficiency of data collection when combined with other
rating events.
The following people participated in the data collection:
Kevin Arndt – Huron County Road Commission
Megan Arndt – Kalamazoo Area Transportation Study
Ken Barnett – Van Buren County Road Commission
Travis Bartholomew – Road Commission of Kalamazoo County
Tim Colling PhD., PE – Michigan Technological University
Anne Dahlquist – Michigan Technological University
Bill DeYoung – Road Commission of Kalamazoo County
Craig Ericksen – Van Buren County Road Commission
Bob Fitzgerald – Antrim County Road Commission
Bruce Holdwick – Huron County Road Commission
Joel Hoort – Van Buren County Road Commission
John Kiefer, PE – Michigan Technological University
Gautam Mani – Southwest Michigan Planning Commission
Doug Mills, PE – Baraga County Road Commission
Fred Nagler, PE – Kalamazoo Area Transportation Study
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 11
Lynne Parker – East Michigan Council of Governments
Luke Peterson – Michigan Technological University
Mark Piotter, PE – Huron County Road Commission
Linnea Rader – Van Buren County Road Commission
Jeffrey Rautiola, PE – Michigan Department of Transportation
Steve Rouser – Western Upper Peninsula Planning & Development Region
Scott Swanson – Baraga County Road Commission
Burt Thompson, PE – Antrim County Road Commission
Sean Thorpe – Michigan Technological University
Pete Torola, PE – Michigan Technological University
4.3.1
Inventory Based Rating Data Collection
The asset management program Roadsoft and the Roadsoft Laptop Data Collector (LDC) were the
tools used for the pilot in order to collect IBR condition data quickly and accurately. Roadsoft is a
GIS-based asset management program used by agencies in Michigan for storing, managing, and
analyzing roadway assets and associated data. Roadsoft and the LDC use a unified base map for the
State of Michigan (Framework base map), allowing data stored in Roadsoft to be related to other
agencies including regional and state level planning and engineering groups. The pilot used
Roadsoft and the LDC because they are likely the tools that would be used in full-scale collection.
Figure 2: Roadsoft data set for Antrim County showing unpaved roads in yellow (gravel) and orange (earth).
Each volunteer agency provided a copy of their Roadsoft database to the project team prior to the
data collection event as displayed in Figure 2. The Roadsoft databases provided an initial inventory
of the unpaved roads of the agencies’ road networks that was used for planning purposes to assess
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 12
routing and the size of collection areas. The project team worked with the individual volunteer
agencies’ management, engineering staff, and foremen to plan each of the data collection events.
The goal of data collection planning was to identify portions of the unpaved road networks that
were representative of the rest of the county and to provide data in areas that would likely be
useful for agency management of unpaved roads. Each volunteer agency had already defined the
unpaved road network from historic data gathering events. For the most part, data collection areas
were subdivided by township since they provided a meaningful reporting block and were indicative
of individual township policy for constructing and maintaining unpaved roads.
All data collected during the pilot were input directly into the LDC with GPS coordinates linking the
rating location to the correct road segment to minimize the chance of transcription or location
errors. The Roadsoft LDC is a software package used to collect data in the field for Roadsoft as
shown in Figure 3. The LDC connects with a recreational-grade GPS unit to provide spatial locations
of the collected data.
Figure 3: Laptop Data Collector showing Huron County IBR collection data.
Field collection of IBR data were completed with a minimum of three raters for safety, with
individuals taking responsibility for driving, data entry into the LDC, and navigation. In many cases,
two to four local agency and regional planning agency staff participated as the rating teams. CTT
staff took the responsibility of entering data into the LDC and did not direct or guide the generation
of ratings from the team to minimize their influence on raw data collection. Data collection
occurred on a continuous basis from the moving collection vehicle. Where necessary, stops were
made to investigate hard-to-see or hidden features. Group consensus determined the IBR number
with each member participating in the rating.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 13
Initial hours of data collection at each county employed frequent physical checks of road width and
ditch depth with a 25-foot hand tape measure to help calibrate the raters to field condition.
Physical checks were also made in instances where raters could not come to consensus on the
correct rating. As data collection progressed, these physical checks became fewer in frequency.
Physical checks of measurements also verified consensus ratings after blind rating exercises (see
section 4.3.2 Gravel Thickness Data Collection).
At random intervals (every 20 to 60 minutes) during the IBR data collection, the teams would
collect blind ratings for a specific segment of road. During blind ratings, each person individually
rated and recorded the IBR data for Surface Width, Drainage Adequacy, and Structural Adequacy
for the current road segment without discussion or measurement. Blind ratings were completed
only with what team members could individually see from their position in the vehicle. Team
members could not exchange information or talk during blind ratings. After all team members had
recorded their blind ratings on individual recording sheets, the entire rating group discussed what
they thought the rating should be until a consensus rating was reached and both Surface Width
and Drainage Adequacy were measured with the tape measure to verify the accuracy of the
consensus measurement. CTT staff recorded the consensus rating in the LDC. The local agency
representative had the final say on the Structural Adequacy portion of the consensus rating since
gravel thickness could not be directly measured in the field during data collection.
Rating productivity data were collected manually by recording start, end, and break times during
the day and logging vehicle miles traveled and miles of road rated at several points in the day
during active collection. The LDC’s tools supplied the rated road mileage data. The productivity
calculation included time to travel to and from data collection areas; however, lunch breaks and
time spent driving to meet the rating team were not included. Rating productivity measures are
representative of the overall average collection rate for the IBR data collection teams without
collecting paved road condition or other data.
4.3.2
Gravel Thickness Data Collection
Following the field collection of the IBR data, CTT staff returned to the pilot counties to collect
gravel depth measurements at random locations that had been previously rated. Gravel depth
measurements were collected by using a core drill or demolition hammer to expose the bottom of
the gravel layer in a shallow pit or hole to verify the actual depth of gravel on the road. Gravel
thickness was measured at the center of the travel lane on one randomly selected side of the road.
Thickness measurements were collected in each county to determine how closely agency staff
using only local knowledge could estimate gravel thickness for the Structural Adequacy category.
CTT staff collected at least nine gravel depth samples in each county on roads with various
Structural Adequacy ratings. CTT staff verified with local agency maintenance staff that no
significant additions or removals of gravel thickness occurred between initial rating and collection
of the gravel thickness measurements.
4.3.3
Combined PASER and IBR Collection
The third and final data collection event occurred only in Baraga County. During the first of the two
days of this collection event, the rating team collected IBR data on unpaved roads and PASER data
on paved roads as the team drove the road network to simulate a joint collection effort. Only
PASER data were collected on the final day of this collection effort to provide a comparison for
PASER data productivity with and without the IBR data. These data will be used to determine the
impact of adding IBR data collection efforts to PASER data collection.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 14
4.3.4
User Feedback
CTT staff collected user feedback and comments on the IBR system from the participants during
the study. They were collected at the training, during rating, and during a post-collection
conference call meeting. This feedback helped to refine the rating system, correct training
deficiencies, and identified areas that needed more thorough explanation during training.
5.0 Results
5.1
Feedback from Users
There were 72 comments received from participants during training, data collection, and the postcollection conference call meeting. After repeat comments were removed, there remained 63
unique comments, which consisted of 13 comments on the software used, 37 comments on the IBR
system, three comments on the training materials, and 10 miscellaneous comments. These
comments are shown in Appendix A: User Feedback and Comments.
5.2
Data Summaries from Collection
The project team collected IBR data from each of the five volunteer counties over the course of
nine days of field collection. Each county had one to two data collection days with the exception of
Baraga County, which had a third collection day where paved PASER data and unpaved IBR data
were collected together. With the exception of the one day of combined collection in Baraga
County, the team strictly collected unpaved road IBR data.
Figures 4 through 7 summarize the IBR data collected during the pilot collection for each volunteer
agency. The figures show the percentage of miles rated for individual IBR elements (Surface Width,
Drainage Adequacy, and Structural Adequacy) as well as the aggregate IBR number. The IBR data
profiles shown in these figures provide a characterization of how unpaved roads were used and
maintained at each agency as part of the transportation system. Figure 8 illustrates the aggregate
IBR number for the entire pilot on a 10-point scale similar to PASER data.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 15
Width Condition of Rated Network
100%
90%
24%
20%
21%
13%
80%
70%
60%
44%
23%
52%
50%
Good
92%
77%
40%
30%
Fair
83%
43%
Poor
54%
20%
27%
10%
0%
7%
Antrim
Baraga
Huron
1%
3%
4%
Kalamazoo
Van Buren
13%
Pilot Total
Figure 4: IBR Surface Width data as a percentage of roads rated during the pilot.
Drainage Condition of Rated Network
100%
3%
3%
17%
90%
80%
5%
29%
38%
38%
70%
41%
60%
45%
93%
Good
50%
27%
40%
30%
Fair
Poor
68%
57%
43%
20%
52%
35%
10%
0%
5%
Antrim
Baraga
Huron
2%
Kalamazoo
Van Buren
Pilot Total
Figure 5: IBR Drainage Adequacy data as a percentage of roads rated during the pilot.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 16
100%
90%
1%
10%
Structure Condition of Rated Network
0%
9%
8%
12%
25%
80%
70%
41%
60%
40%
39%
97%
50%
88%
90%
86%
Good
Fair
Poor
30%
46%
20%
36%
10%
0%
6%
Antrim
Baraga
2%
Huron
Kalamazoo
Van Buren
1%
Pilot Total
Figure 6: IBR Structural Adequacy data as a percentage of roads rated during the pilot.
100%
90%
0%
Percent of Each Agencies Roads Rated
7%
14%
11%
7%
80%
43%
47%
70%
43%
60%
87%
Good
50%
40%
85%
23%
87%
Poor
30%
46%
20%
51%
34%
10%
0%
Fair
10%
Antrim
Baraga
Huron
3%
2%
Kalamazoo
Van Buren
Pilot Total
Figure 7: Combined IBR number as a percentage of roads rated during the pilot.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 17
IBR Ratings Collected During the Pilot All Agencies
40%
35%
30%
25%
20%
15%
10%
5%
0%
9
8
Good
7
6
5
Fair
4
3
2
1
Poor
Figure 8: Converted 10-point scale IBR numbers collected during the pilot. Note that rating of 10 is reserved for new
construction.
5.2.1
Antrim County
The collection rate of IBR data in Antrim County was the slowest of all the pilot counties at an
average of 6.3 miles rated per hour over the course of the two days of collection. Antrim County
was classified as a Low Volume Terminal Branch Network because its population was less than
100,000 people [8] and more than 40 percent of the land area was covered by forests [9]. Data
collection teams rated almost 72 miles of road segments as shown in red on Figure 9. A large
portion of the network that was rated consisted of short-length, low-volume, seasonal, dead-end
roads. Conditions on these unpaved roads necessitated low travel speeds as depicted Figure 10.
The presence of many lakes and streams further divided the county and made efficient travel
difficult.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 18
Figure 9: Antrim County pilot data collection. IBR data collected on roads highlighted in red.
Unpaved roads in Antrim County generally had narrow road widths, no drainage, and no structure
(gravel thickness) leading to overall low IBR scores. During the IBR data collection, several unpaved
roads illustrated on the Framework base map terminated early or were non-existent. The data
collection effort provided a means for verifying and correcting the far terminal ends of the
Framework base map to better define the public road system in Michigan. It also provided county
staff with a means for checking for encroachment and documenting road right-of-way
“maintenance” activity to guard against forced abandonment legal actions.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 19
Figure 10: Antrim County unpaved road showing poor Surface Width, poor Drainage Adequacy, and poor Structural
Adequacy.
5.2.2
Baraga County
The IBR data collection in Baraga County proved to be slower than anticipated from a productivity
standpoint. The rating teams collected 99 miles of unpaved road IBR data in two days of collection
as depicted in red in Figure 11. Baraga County was classified as a Low Volume Terminal Branch
Network for the IBR pilot because its population was less than 100,000 people [8] and more than
40 percent of the land area was covered by forests [9]. Unpaved roads in Baraga County provide
mostly seasonal or very low volume access to recreational and forest properties. Most of these
gravel roads were located at the far ends of the road network, typically dead-ending at a property
boundary. These characteristics required more total miles of travel to rate a road segment due to
backtracking and long transits between relatively short unpaved road segments.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 20
Figure 11: Baraga County pilot data collection. Ninety-nine miles of IBR data were collected on roads highlighted in red.
The height of roadside vegetation in Baraga County greatly complicated data collection by
obscuring the presence of ditches. Figure 12 illustrates the difficulty with rating during June and
July when vegetation was at its fullest. In many cases, it was nearly impossible for the rating team
to determine ditch depth without stopping, exiting the vehicle, and sending a member of the rating
team down to probe the ditch.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 21
Figure 12: Thickly vegetated roadsides in Baraga County. Note that there was a significant (good) ditch on both sides of
this road that was obscured by grass and other vegetation.
In general, unpaved roads in Baraga County were narrow (usually only slightly wider than one lane)
had minimal drainage, and had little or no structure (gravel thickness), this lead to overall low IBR
scores. While all of these characteristics would be expected and are generally appropriate for
short, very low-volume, low-speed, unpaved roads that primarily serve as access to a few rural
properties, almost all of the non-seasonal unpaved roads rated in Baraga County would provide
better service to users if they were properly ditched and had the addition of more gravel.
5.2.3
Huron County
Huron County was classified as an Agricultural Grid Network for the IBR pilot because its population
was less than 100,000 people [8], less than 40 percent of the land area was covered by forests [9]
and the road network follows a strong one-mile-long section line grid pattern. The Huron County
rating team collected 245 miles of IBR data in less than nine hours, which was the most productive
collection county in the pilot. IBR data on Agricultural Grid Networks can be collected very
efficiently since there is little need for backtracking due to high connectivity, and the road
conditions allow for higher speed of travel. Overall, 85 percent of the travel in Huron County was
on unpaved road segments being actively rated. The terrain of Huron County has very flat vertical
elevation changes and few horizontal curves as depicted in Figure 14. The interconnected unpaved
grid pattern created by the section lines, as shown in Figure 13, increased collection speeds
because it allowed for long collection runs through entire townships.
Huron County’s unpaved roads were generally wide, fully ditched, and contained significant
structural gravel layers; this led to high IBR scores. These types of roads allow higher speed,
volume, and travel loads. Unpaved roads in Huron County are relied upon to connect one location
to another (farm to market roads) and, generally speaking, were not dead ends of the system. In
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 22
fact, all of the townships where data were collected for the pilot had significantly more unpaved
miles of road than paved miles as observed in Figure 13.
Figure 13: Huron County pilot data collection. IBR data collected on roads highlighted in red.
Figure 14: Huron County unpaved road showing good Surface Width and good Drainage Adequacy.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 23
5.2.4
Kalamazoo County
Kalamazoo County was classified as a Suburban Residential Network for the IBR pilot because its
population was over 100,000 [8]. Data for the entire 103-mile network were collected in one day
and are illustrated in Figure 15. The Kalamazoo County unpaved network was concentrated along
the Kalamazoo County borders and away from the City of Kalamazoo. The land use of the unpaved
road network was predominantly agriculture and rural residential as depicted in Figure 16.
Figure 15: Kalamazoo County pilot data collection. IBR data collected on roads highlighted in red.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 24
Figure 16: Kalamazoo County unpaved road showing fair Surface Width and poor Drainage Adequacy.
5.2.5
Van Buren County
In Van Buren County, the rating teams collected 141 miles of IBR data in two days with two local
agency employees and one planning agency employee on the first day and three local agency
employees on the second day. The collection rate was 11.4 miles per hour over the two days of
collection. The land use for Van Buren County was mostly rural residential and agricultural. The
population of Van Buren County was less than 100,000 people [8] and less than 40 percent of the
land area was covered by forests [9] so it was classified as an Agricultural Grid Network for the IBR
pilot.
The unpaved network was interconnected with paved roads so segments usually only had to be
driven once as shown in Figure 17. Van Buren County had more paved roads compared to Huron
County, so there was more traveling between unpaved segments to collect data. As with Baraga
County, many of the unpaved roads had high grass along the shoulders that made assessing
Drainage Adequacy difficult. Figure 18 shows a typical unpaved road in the Van Buren County road
network.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 25
Figure 17: Van Buren County pilot data collection. IBR data collected on roads highlighted in red.
Figure 18: Van Buren County unpaved road with fair Surface Width and fair Drainage Adequacy.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 26
5.3 Benchmarking Rating Productivity
Productivity benchmarking can be used to forecast the time commitment for collecting the IBR
system data for gravel roads in the state of Michigan as part of a wider effort. The data collection
speed of the IBR system was recorded and calculated for each pilot county individually to take into
account their unique geographic and road network features. Many factors influenced the collection
speed of the IBR system. The main factors were the type of network (Low Volume Terminal Branch
Networks, Agricultural Grid Networks, or Suburban Residential Networks), which related to the
connectivity of the unpaved roads, and the condition of the road being rated, which determined
travel speed. The time of the year that the IBR condition is assessed is also a factor on collection
speed. Data collection later in the growing season is likely to be more difficult and less reliable
since Drainage Adequacy features can become hidden in roadside vegetative growth. A summary
of the IBR data collected during the pilot is shown in Table 1. Collection time was calculated based
on the time actively rating roads or transiting to and from rating areas. Breaks for lunch and
switching of rating crews were deducted from actual productive rating time.
County
Collection
Time (Hr)
Gravel
Miles Rated
Rating
Productivity
(Miles/Hr)
Total
Miles
Driven
Travel
Speed
(Miles/Hr)
Miles Rated/
Total Driven
Antrim
11.50
71.976
6.3
234.5
20.4
31%
Baraga
11.33
99.205
8.8
238.0
21.0
42%
Huron
8.67
245.185
28.3
289.0
33.3
85%
Kalamazoo
9.92
103.163
10.4
314.0
31.7
33%
Van Buren
12.42
141.524
11.4
318.0
25.6
45%
Total
53.83
661.053
12.3
1393.5
25.9
47%
Table 1: IBR data collection statistics by county. Statistics are indicative of collecting only IBR data
on unpaved roads.
5.3.1
Combined PASER/IBR Collection Benchmarking
In Baraga County, there were four days of data collection. During the first two days, only IBR data
were collected and resulted in just over 99 miles being collected at a rate of 8.8 miles collected per
hour. The IBR and PASER data were collected together on the third day and resulted in 40.9 miles
of gravel IBR data and 110.4 miles of paved PASER data being collected for a total of 151.3 miles of
data collected at a rate of 20.9 miles collected per hour. Only PASER data were collected the fourth
day and it resulted in 81.6 miles of paved PASER data being collected at a rate of 14.8 miles
collected per hour. The rate when collecting IBR data and PASER data together was higher than
when collecting PASER data only or when collecting IBR data only due to the minimization of roads
traveled without rating. A summary of the data collection from Baraga County is shown in Table 2.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 27
Collection Event
Collection
Time (Hr)
Road Miles
Rated
Rating
Productivity
(Miles/Hr)
Total
Miles
Driven
Travel
Speed
(Miles/Hr)
Miles Rated/
Driven
Baraga IBR Only
11.33
99.205
8.8
238
21.0
42%
Baraga PASER Only
5.50
81.588
14.8
151
27.5
54%
Baraga PASER & IBR
7.25
151.345
20.9
226
31.2
67%
Table 2: IBR data and joint IBR and PASER data collection statistics.
5.3.2
System Wide IBR Collection Estimates
The overall average data collection rate for the pilot collection was 12.3 miles collected per hour
while using the IBR system to collect only unpaved roads. Using this average, it would take roughly
3,200 hours of data collection to capture the estimated 40,000 centerline miles of unpaved roads in
Michigan. This would equate to an average of just under 40 hours of collection per county in
Michigan if IBR data were collected on its own.
Segregating counties by their road network classification (see Figure 1) results in 46 counties in the
Low Volume Terminal Branch Network category, 17 counties in the Agricultural Grid Network
category, and 20 counties in the Suburban Residential Network category. Assuming average
collection rates from the pilot and assuming that unpaved roads are evenly distributed in each
county provides the following estimates of time to collect the unpaved road network:
Low Volume Terminal Branch Network
(8.8 mph + 6.3 mph) / 2 = 7.55 mph average collection speed.
46 counties X 481 miles per county / 7.55 mph = 2,930 hours
Agricultural Grid Network
(28.3 mph + 11.4 mph) / 2 = 19.85 mph average collection speed.
17 counties X 481 miles per county / 19.85 mph = 411 hours
Suburban Residential Network
20 counties X 481 miles per county / 10.4 mph = 925 hours
Total Hours
2930 hours + 411 hours + 925 hours = 4,260 hours total
The estimate of time necessary to collect unpaved road conditions based on segregating counties
by network classification results in an estimate of approximately 4,300 hours of data collection, or
roughly 52 hours of collection per county in Michigan if the IBR data were collected as a unique
data collection event.
The Baraga County combined PASER and IBR data made significant improvements on the
productivity of IBR or PASER collection alone. Combined data collection was 41 percent more
productive than PASER collection alone in Baraga County. While it is unlikely that this percentage of
gain will be observed with other types of networks, the project team believes that combined
collection rates of around 20 mph are likely long-term average collection rates. This would mean
during a combined collection event the 40,000 center line miles of unpaved road would require
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 28
only 2,000 hours (approximately 24 hours per county) to collect as a combined effort with PASER
data if 100 percent of the unpaved roads were collected. If only half the miles of unpaved roads
were collected during a joint pavement collection event with PASER data, then the level of effort is
reduced to only an additional 12 hours per county. System-wide estimates are included in Table 3.
Estimation Method
Rating Productivity
(Miles/Hr)
Time to Collect 40K
Unpaved Miles (Hr)
Average Time
per County (Hr)
12.3
3,252
39
7.55 to 19.85
4,260
52
20
2,000
24
IBR only (average rate)
IBR only (segregated by county type)
Combined PASER and IBR
Table 3: System-wide IBR data collection estimates.
5.4
Repeatability of Measurement
The repeatability of the IBR system was evaluated by several different metrics that compared
periodic blind individual ratings against the group consensus rating – ground truth – for specific
segments. Repeatability was assessed for individual IBR elements (Surface Width, Drainage
Adequacy and Structural Adequacy) as well as the overall combined IBR number. The pilot
collected 281 blind rating sets from 58 road segments that were divided roughly equally between
the five pilot counties.
Evaluating each of the rating elements individually found that blind ratings matched ground truth
92.2 percent of the time for Surface Width, 85.1 percent of the time for Drainage Adequacy, and
90.7 percent of the time for Structural Adequacy. The pilot team felt that the thick vegetation
negatively influenced the agreement on Drainage Adequacy ratings since raters were not asked to
leave the vehicle to take a closer look or measure ditch depth during blind ratings.
Further analysis of the repeatability of individual IBR elements was completed by subtracting the
point value for each rating element (Surface Width, Drainage Adequacy and Structural Adequacy)
of the blind rating from the same element on the ground truth rating (see the report, Inventory
Based Assessment Systems for Unpaved Roads [1] for more details on how point values were
calculated). Figure 19 illustrates the point spreads for each rating element when compared against
ground truth. The high match percentages and low points spread for each rating element indicates
that each rating team member was accurately and consistently perceiving road conditions during
rating.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 29
Blind Rating vs. Ground Truth
100%
90%
Percent of Ratings
80%
70%
60%
50%
40%
30%
20%
10%
0%
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
7
8
9
IBR Rating Point Difference (Blind Rater - Ground Truth)
Width
Drainage
Structure
Figure 19: IBR element point difference (rater minus ground truth)
Comparing aggregate point values from blind ratings against the ground truth aggregate IBR data
indicated that 72.2 percent of the aggregate blind IBR data exactly match ground truth, and 92.9
percent of blind IBR data were within a tolerance of +/- one rating point. The aggregate IBR point
results are plotted in Figure 20.
The TAMC collects quality control ratings on PASER data collected as part of its annual paved road
data collection. Historical Rating Team - QC agreement for PASER data are plotted in Figure 20 as a
basis of comparison for IBR agreement. Historic PASER QC agreement data are provided for the
best match year (2008) and the worst match year (2004).
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 30
IBR Number Difference (Rater - Consensus) and
High and Low PASER Rating Difference (Rating Team - QC)
100%
90%
Percentage of Ratings
80%
70%
60%
50%
40%
30%
20%
10%
0%
-9
-8
-7
-6
-5
-4
High PASER Diff. (2004)
-3
-2
-1
0
1
2
3
4
Low PASER Diff. (2008)
5
6
7
8
9
IBR Pilot (2015)
Figure 20: IBR number difference for all pilot segments and PASER results for paved road segments as a basis of
comparison for data collection repeatability.
Ground truth for the IBR elements Surface Width and Drainage Adequacy were both readily
observable and verifiable by direct field measurement. Structural Adequacy, however, was not
directly measurable during the rating data collection. Following the completion of rating data, CTT
staff drilled test holes on at least nine randomly selected road segments per county that were
rated during the pilot. The gravel thickness observed in the test holes was compared to the bin
range for Structural Adequacy ratings (i.e. eight inches or more, seven to four inches, less than four
inches) to assess the accuracy of the rating estimates made by using local institutional knowledge.
Actual gravel thickness measurements that were within the bin range of the consensus rating were
considered a match. When actual gravel thickness was outside of the bin range, the actual gravel
thickness was subtracted from the upper or lower bounds of the bin range to determine the error
amount. For example, the error of an actual measurement of two inches of gravel on a segment
rated fair for Structural Adequacy would be calculated as:
Actual thickness – Lower bin range = error amount OR 2 - 4 = -2
Figure 21 illustrates the error between actual measures and the outer bounds of the three bin
ranges for gravel thickness used to evaluate Structural Adequacy. Actual gravel thickness data in
Figure 21 illustrates that local agency staff were correct 79.6 percent of the time when selecting
bin ranges of gravel thickness. In the 20.4 percent of thickness measurements that were not exact
matches, it was more likely that raters would overestimate gravel thickness.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 31
Actual Thickness Minus Rater Category Boundary Thickness
(Inches)
90%
Percent of Core Samples
80%
70%
60%
50%
40%
30%
20%
10%
0%
-4.0
-3.5
-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
Negative Thickness is the Rater's Overestimation
0.0
--
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
Positive Thickness is the Rater's Underestimation
Figure 21: Validation of the institutional knowledge on gravel thickness.
6.0 Conclusions
6.1
Recommendation for Modification of the Original System
Overall user feedback was very positive and helpful. Of the 63 unique comments that were
received, 26 comments were not addressable and only documented in Appendix A: User Feedback
and Comments. The remaining 37, also addressed in Appendix A, indicate the action to be taken to
modify the IBR system, training materials, and/or software.
6.1.1
Modifications to the Drainage Adequacy Measurement Rating Guidance
During the pilot study in Antrim County, it was suggested to rate only the worst side of the road
when assessing Drainage Adequacy to simplify the number of cases. This change removed one of
the special cases that was developed to define Drainage Adequacy when there was differing
conditions on each side of the road. The original IBR system used during the pilot dictated a rating
of fair for Drainage Adequacy when there was good Drainage Adequacy on one side of the road
and poor on the other. The revised rating rule suggested by Antrim County Engineer Burt
Thompson dictated that this Drainage Adequacy condition be rated as poor. This greatly simplified
the rating guidance by matching the rest of the special Drainage Adequacy guidance that was
created, which conformed to the idea of rating the worst side. The IBR system was updated after
the completion of the pilot to acknowledge this recommendation.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 32
6.1.2
Modifications to the Structural Adequacy Measurement Rating Guidance
During the pilot, the guidance for gravel thickness for the Structural Adequacy rating was noncontiguous between the good and fair category. The original IBR guidance used during the pilot
suggested that roads with good Structural Adequacy have eight inches or more of gravel and roads
with fair Structure Adequacy have seven inches to four inches. The revised good Structure
Adequacy category eliminated the gap in the original guidance by changing the good range from
eight inches or more to greater than seven inches.
Several agencies made suggestions for modifying the range of thickness for the Structural
Adequacy category based on practices in their individual agencies. In response to the suggestions,
CTT staff revisited the guidance used to create the subdivisions for the IBR system.
The AASHTO Design Catalogs [6, 10] provide a recommended aggregate base thickness for unpaved
roads when not enough detailed information is available to use a more in-depth road design
analysis. The thickness recommendations from AASHTO are categorized into United States Climatic
Regions. Michigan is in Climatic Region III and the recommended aggregate thickness ranges from
six inches to 17 inches depending on how much traffic is on the road and the quality of the
subgrade as summarized in Table 4. The majority of the recommended aggregate thicknesses given
are very close or exceed the greater than seven-inch measure for the IBR system good rating,
which is consistent with AASHTO design guidance. Based on this review, the good Structural
Adequacy ranges for the IBR system were not modified.
Traffic Level
Relative Quality
of Roadbed Soil
High
Medium
Low
Very Good
15
11
6
Good
17
12
7
Fair
17
12
7
Poor
*
*
9
Very Poor
*
*
10
* Higher type pavement design recommended
Table 4: U.S. Climatic Region III recommended aggregate base thickness from the AASHTO Design
Catalogs given in the Gravel Roads Maintenance and Design Manual [3].
6.1.3
Concerns Over the Intent of Good-Fair-Poor Designations
Local agencies expressed concern over the stigma of using good, fair, and poor as designations on
the rating scale. During training, agencies were instructed that the good-fair-poor designations
were intended to relate how far away from the baseline condition the inventory feature was and
that they were not an indictment or endorsement on the condition of the network. However even
with this guidance, agency staff were still concerned about how such ratings would reflect on their
road network. This similar issue was observed when Michigan began performing statewide PASER
collection but, with experience and education, the stigma passed. The project team believes that
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 33
with proper education on what the IBR system is and is not, these concerns should be short-lived
with a larger implementation.
6.2
Repeatability/Reliability of the System
The repeatability of the IBR system was very high both on individual inventory features as well as
the aggregate IBR number when consensus ratings (control) were compared to individual blind
ratings. Individual raters using the IBR system were identical to the control rating (group
consensus) 72.2 percent of the time for all three IBR factors, and 92.9 percent of blind IBR data
were within a tolerance of +/- one rating point from the control. Comparatively, in 2008, which was
the best year for PASER agreement between the rating team and quality control, only 48 percent of
ratings were exact matches between rating teams and the quality control rater, and 86.6 percent
were within a tolerance of +/- one rating point from the control.
The Drainage Adequacy rating element had the lowest exact match percentage when rated blindly
versus the control at 85.1 percent exactly matching. This often resulted from tall grass in the
shoulder of the roadway blocking the view of ditches that were there. The repeatability of
accessing the Drainage Adequacy feature would be expected to increase if data collection occurs
when the grass is low (recommended below in the next section) or if raters are allowed to exit the
vehicle to assess the roadway.
Local agency staff correctly classified gravel thickness in one of three ranges using local knowledge
and surface observations 79.6 percent of the time. Errors in thickness estimates were biased
toward overestimating gravel thickness when estimates did not fall into the correct bin of ranges.
The high level of success for estimating the existing gravel thickness of unpaved roads during this
pilot illustrated that local agencies have a good understanding of the structure of their roads.
Because of the ability to accurately estimate gravel thickness, it is recommended that the training
and guidance materials for the IBR system be reworked to provide guidance for assessing structural
distresses secondarily after assessing the actual gravel thickness when rating Structural Adequacy.
6.3
Recommendation for Implementation (Policy for Collection)
The pilot data collection used a temporarily modified version of the Roadsoft Laptop Data Collector
(LDC) to collect and store data. This modified version of the LDC repurposed existing data fields to
collect IBR data. While this was an inexpensive solution for the pilot, larger data collection on a
local or state level will require permanent changes to the LDC and the TAMC’s data collection
process. The 2016 TAMC Activities Work Plan includes tasks to modify the LDC to account for the
IBR data collection. Completion of this work will allow potential IBR data collection to start as early
as April 2017. Nine recommendations for implementation can be made:
First, it is recommended that IBR data be collected during periods when roadside vegetation is
dormant in the spring or has been cut with a roadside mowing program. Findings showed that
roadside vegetation significantly influenced the Drainage Adequacy assessment by obscuring the
ground.
Second, it is recommended that the TAMC require updates of IBR numbers on all gravel roads after
the completion of any project that changes IBR features (ditching, widening, addition of gravel,
paving project). The pilot agencies involved in this project indicated that IBR data for the entire
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 34
state should be initially collected over a one- to two-year period until at least one full census of all
gravel roads is produced. Once the initial IBR collection is completed, the IBR number of the
roadway does not change very quickly outside of where rehabilitation or reconstruction projects
are completed. This method would tie investment reporting to updating the IBR condition, which
would be easiest in Roadsoft as projects are completed.
Third, it is recommended that after the initial collection of IBR data, the re-rating of the entire
network be completed on a three- or four-year cycle to inspect for changing conditions outside of
construction projects. This allows detection of changes in rating due to loss of gravel or ditch
sedimentation.
Fourth, it is recommended to rate seasonal roads using the same criteria and techniques as nonseasonal roads, including initially completing seasonal rating on the same cycle. Seasonal roads
should be flagged as such using the appropriate fields in the LDC during data collection. The
seasonal/non-seasonal distinction will allow future decisions on management and data collection
to be made, as well as providing a means for segregating these two types of roads when data are
presented.
Fifth, it is recommended to collect IBR and PASER data at the same time to improve efficiency of
collection.
Sixth, it is recommended to reimburse IBR data collection using the same policy and procedures
that are used for PASER data collection including the reimbursement of time to collect the data.
Seventh, it is recommended that the TAMC require training for IBR data collection consistent with
PASER training. IBR training could be incorporated into the existing training program by adding an
additional one to two hours of training. Initially, IBR training should be required annually until the
full census of data are collected at least once.
Eighth, following the completion of the collection of the full system, it is recommended that
updated IBR data be required on the same cycle as PASER training.
Finally, it is recommended to update the training materials, reference handouts, and software to
account for the comments that are called out as actions in Appendix A.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 35
References
[1] Michigan Transportation Asset Management Council (TAMC), M. T. A. M. C. (2013). Michigan's
Roads & Bridges 2013 Annual Report. Michigan Transportation Reporting Portal, Michigan
Transportation Asset Management Council. Retrieved on July 17, 2014 from
http://www.mcgi.state.mi.us/MITRP/Contact/Reports.aspx
[2] Walker, D., Entine, L., & Kummer, S. (2002). Pavement Surface Evaluation and Rating (PASER)
Asphalt Roads Manual. University of Wisconsin-Madison: Wisconsin Transportation Information
Center. Retrieved on October 11, 2011 from
http://epdfiles.engr.wisc.edu/pdf_web_files/tic/manuals/Asphalt-PASER_02.pdf
[3] Walker, D., Entine, L., & Kummer, S. (2002). Pavement Surface Evaluation and Rating (PASER)
Concrete Roads Manual. University of Wisconsin-Madison: Wisconsin Transportation Information
Center. Retrieved on October 11, 2011 from
http://epdfiles.engr.wisc.edu/pdf_web_files/tic/manuals/Asphalt-PASER_02.pdf
[4] Walker, D., Entine, L., & Kummer, S. (2001). Pavement Surface Evaluation and Rating (PASER)
Sealcoat Manual. University of Wisconsin-Madison: Wisconsin Transportation Information Center.
Retrieved on October 11, 2011 from
http://epdfiles.engr.wisc.edu/pdf_web_files/tic/manuals/Sealcoat-PASER_01_rep13.pdf
[5] Brooks, C., Colling, T., Watkins, M. K., Roussi, C., & Endsley, A. (2014). Deliverable 2-A: State of
the Practice of Unpaved Road Condition Assessment Characterization of Unpaved Road Condition
through the Use of Remote Sensing: Michigan Technological University (MTU_ and the U.S.
Department of Transportation Research and Innovative Technology Administration (USDOT-RITA).
Retrieved from http://www.mtri.org/unpaved/
[6] Skorseth, K., & Selim, A. (2000). Gravel Roads Maintenance and Design Manual. Washington,
D.C.: South Dakota Local Transportation Assistance Program (SD LTAP), Federal Highway
Administration. Retrieved on September 2, 2011 from
http://water.epa.gov/polwaste/nps/gravelroads_index.cfm
[7] Colling, T., & Watkins, M. K. (2014). Inventory Based Assessment Systems for Unpaved Roads.
Michigan Technological University (MTU).
[8] U.S. Census Bureau. Michigan – 2010 Census Results total Population by County. Retrieved on
October 1, 2015 from United States Census 2010:
https://www.census.gov/2010census/news/releases/operations/cb11-cn106.html.
[9] Michigan Geographic Alliance and the Science/Mathematics/Technology Center. Percentage of
Land Area in Forests: Central Michigan University. Retrieved on October 1, 2015 from
http://geo.msu.edu/extra/geogmich/forestry.html.
[10] National Cooperative Highway Research Program (1993). Chapter 4. AASHTO Guide for Design
of Pavement Structures (pp. 11-69): American Association of State Highway and Transportation
Officials.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 36
Appendix A: User Feedback and Comments
13 Software Comments
Need a way to uncheck rating box or clear rating
Provide ability to switch easily between the IBR (gravel)
collection and PASER (paved) collection in LDC for use when
rating both at the same time
In the LDC for collection do not create
gravel/earth/undefined network to use for the IBR data
collection. Instead, export entire system into LDC. We found
several segments where the surface type was incorrect (i.e.,
defined as Asphalt but actually Gravel) but by filtering
segments were not in the chosen network so we could not
revise. Agency person must know system to identify
candidates for the IBR collection, cannot use LDC tools to
identify percent collection complete when the entire network
is imported.
In LDC, add a text box to note odd situations (i.e., Baraga
Plains Drainage Adequacy)
In LDC, reorder Width-Drainage-Structure categories to
match reference handout
In LDC, add a text box for ways to record maintenance items
that are needed (i.e., cut ditch on West side)
See the IBR number in the LDC after rating the segment
See the physical width measurement in the LDC
The GPS cross in the LCD should be a different color than the
road colors (not black, red, or green)
During collection, we documented a lot of missing signs and
private gates as well as certification mileages that may not be
maintained. May want to bring certification maps. Jones Road
in Antrim in Milton Township - road on map but not present
in LDC.
Found many roads on map that were not present or ended
prior to line work on map suggested. This would lead to
significant improvements to the Framework base map. Need
a process to collect these changes.
Maps in Roadsoft need to be printer friendly. Their township
people are visual and the Roadsoft reports are not used by
them.
Use pavement sub-type descriptions like “Graded Earth
Seasonal” and “Graded Earth Non-Seasonal” to further
identify unpaved roads.
Update LDC
Action
Update LDC
Update training material
Update Roadsoft/LDC
Update LDC
Update Roadsoft/LDC
Update LDC
Do not Do unless local agency
needs data. Collecting the actual
width would slow down collection
speed. It may also influence the
rater when rating for the current
year.
Update LDC
Update training material
Include a way to flag non-existent
roads in LDC, so agencies can
request a change in Frame Work
map.
Noted
Recommend that agencies create
Gravel Surface Subtypes in
Roadsoft to help manage and
report seasonal roads
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 37
37 System Comments
When a segment has two different kinds of ditches, use the
worst ditch rating for Drainage Adequacy. This only changes
the poor/good rating from fair as it stands now to poor under
the new guidance. This greatly simplifies rating guidance.
Need to rate each year for first years of rating, to develop a
pattern and consistency.
Do pilot with TAMC staff and members to collect data on
unpaved roads too. Antrim will host tour.
Enter data in office from historical knowledge then
verify/revise in field data collection.
Allow for consideration of soils in rating for Drainage
Adequacy and/or Structural Adequacy. Example: minimal
gravel over rock where there are no structural issues but is
currently considered poor.
Consideration in the rating system as to if the road is built to
a standard, in particular for horizontal and vertical alignment.
We are interested in this data for planning projects with the
townships
How do we rate Structural Adequacy on roads that have large
rocks on the surface (mine rock with little fine aggregate)?
Suggested de-rating by one category since a top dressing of
gravel would make these types of roads good.
How do we deal with roads that flood due to seasonal
conditions, i.e., - near a river?
For Drainage Adequacy: road can't be used as storage
It would be nice to have another Surface Width category:
poor and really poor (only passable with 1 car)
Action
Rate the worst side for Drainage
Adequacy. Update training
material.
The results of the pilot study show
that the existing training is
adequate for the IBR system. It is
recommended to update the
training as indicated in this
comment list.
Do a demonstration.
Do this for Structural Adequacy
assessment only. (Update training
material)
Rate by how much existing gravel is
there. The rock outcroppings were
isolated and would not influence
the rating of the whole segment.
Do not do. The costs would be too
variable.
Noted
Agree. (The cost of stone is on the
road. The mine rock was hauled in
to create a stronger structure)
Rate the typical condition for the
year. (Seasonal flooding may be
typical every year, but it is not
typical for the whole year.)
Agree, if this is the typical condition
for the whole year.
Do not Do. This seemed only
applicable to Seasonal Roads.
Suggest creating a comment box in
the LDC for local agencies to make
additional comments like these.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 38
Rate all roads using the same
system and let each agency set
their own policy. For example, “it is
acceptable for roads that are on
sand soil to have less than 6 inch
deep ditches." At a network level,
the cost to upgrade the sand soil
roads to a 2-foot ditch is still
captured.
Baraga Plains Rd has “good” drainage but Drainage Adequacy
was not rated good because of the shallow ditches and the
well-draining sand soil. How should this be rated?
Baraga would use the IBR system as a management tool. Go
to townships and show them what needs to be fixed and
what it would take to fix them. (i.e., add gravel to go up a
rating number)
Noted
Rate before the grass grows or after it has been cut
(April/May or September/October) because tall grass makes it
difficult to rate Drainage Adequacy.
Update training material
Rate the worst side. (Update
What about situations where half the road was rebuilt?
training material)
It would make the most sense to rate Fed-Aid, Paved Local
and Gravel all at the same time.
Noted
Baraga felt that collecting IBR and PASER together was slower See results in Section 5.3.1
than PASER alone. IBR collection alone seemed to be close to Combined PASER / IBR Collection
the same as PASER alone.
Benchmarking in report.
Huron County was concerned that road ratings would be used
to take away their funding because they have good roads.
Noted
Do not change. (See Grave Roads
Maintenance and Design Manual
and explanation in Section 6.1
Recommendation for Modification
of the Original System in this
4 inches may be too much for upper limit of poor
report)
Do not change. (See Grave Roads
Maintenance and Design Manual
and explanation in Section 6.1
Recommendation for Modification
Change Structural Adequacy categories to: 0-3 inches = poor, of the Original System in this
3-5 inches = fair, >5 inches = good
report)
Two foot ditches are present but the water can't get there
Address this in training (this is a
because of a six inch berm so rate it poor
secondary ditch)
Van Buren would use the data to aid townships in setting
budgets
Noted
Van Buren is looking forward to using the system instead of
Gravel PASER Manual. They like the IBR system.
Noted
Van Buren would like something like IBR for Paved Roads
Noted
The training that was received as part of the pilot is adequate
for the IBR system. It is a simple system to use.
Noted
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 39
The beauty of the system is the ratings are not going to be
changing quickly over time. Periodic changes due to
construction can be recorded in Roadsoft.
When rating the Structural Adequacy thickness, use "Local
Gravel" and "Primary Gravel" with different criteria.
When using IBR, you get a more consistent overall rating than
when using PASER Gravel Manual.
We can use IBR to recommend projects to townships
I fully support IBR at a statewide level
Breaking the Structural Adequacy portion into "Local Gravel"
and "Primary Gravel" would complicate the system
Drainage Adequacy was the hardest to assess. 1 - Vegetation
growth blocked the view of ditches. 2 - There might not be a
defined ditch but water still drains away from the road. 3 Some roads do not need to have 2' deep ditches on both
sides due to soil conditions.
The IBR system is good as-is. A couple tweaks could be made,
but assemble comments and move forward.
Noted
Do not do. This complicates the
system by introducing policy
decisions. One agency may view 4
inches to be considered good and
another may consider 6 inches to
be considered good. It is
recommended to rate all roads
using the same system, and let
each agency set their own
individual policy. For example, "it is
acceptable for low volume seasonal
roads to be rated poor and have
less than four inches of gravel." At a
network level, the cost to upgrade
the low volume seasonal roads to
an IBR of good is still captured by
using the current system levels.
Noted
Noted
Noted
Agree
1 - Recommend only collecting
Drainage Adequacy data when
grass is low. 2 - Update handout
and training materials to reflect
that drainage is what is important
and there does not necessarily have
to be defined ditches if water is
falling away from the road and
there is measureable vertical
separation. 3 - Rate all roads using
the same system and let each
agency set their own policy. For
example, it is acceptable for roads
that are on sand soil to have less
than 6-inch deep ditches. At a
network level, the cost to upgrade
the sand soil roads to a 2-foot ditch
is still captured.
Noted
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 40
IBR can be used to come up with a cost estimate to upgrade
our system.
Collect the data in one year
It may take two years to collect the data
Noted
Noted
Noted
Have a split screen with IBR/PASER to help in dual collection
but do not shrink the size of the map size in the LDC.
Agree. Update the LDC.
3 Materials Comment
"Ditches" may be a misleading term in the cheat sheet since
we are looking at Drainage Adequacy
Make Potholes and Ruts secondary on the cheat sheet.
Add info on drainage falling away from the road but no
defined ditches.
10 Miscellaneous Comments
It would be nice to have maintenance personnel available
during rating to help in rating for thickness and high weeds to
know what is there.
Agriculture is large part of the economy in Van Buren County,
so they need enough structure in their roads
Kalamazoo has a lot of gravel on their roads in some of their
townships. They only have to grade once or twice a year after
Spring thaw
Some of Van Buren townships add about 5000 tons of gravel
every year.
Huron County does not have seasonal roads. They have
unimproved roads that do not have elements like gravel
thickness, width or drainage.
Huron County has drain tile down the center of most roads.
Van Buren rates every road in the county every year
Kalamazoo rates their Gravel Roads every 3 years using PASER
Gravel Manual
It is rare to have more than 7 inches of gravel on a road that
Huron County Employees consider “good” in Huron County.
Using the IBR system is a good way to document when a road
has been traveled by our agency for maintenance records
too.
Action
Update training material by
replacing "ditches" with "Drainage"
were appropriate.
Update handout
Update handout
Action
Updating training material
Noted
Noted
Noted
Noted
Noted
Noted
Noted
Noted
Noted
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 41
Appendix B: Draft TAMC Policy for Collection of Roadway
Condition Data on Federal-Aid Eligible Roads & Streets
This document is based on the policy adopted by The Transportation Asset Management Council on
February 6, 2013.
To view the policy go to http://tamc.mcgi.state.mi.us/MITRP/Council/Policies.aspx
Introduction:
The Transportation Asset Management Council (TAMC) was established to expand the
practice of asset management statewide to enhance the productivity of investing in
Michigan’s roads and bridges. Part of the TAMC’s mission is to collect physical inventory
and condition data on all roads and bridges in Michigan. This document describes the
policy and procedures for collecting the physical inventory and condition data on the
federal-aid eligible roads & streets of the State.
Requirements:
According to Act 51 (P.A. 499 2002, P.A. 199 2007); each Local Road Agency and the
Department of Transportation shall annually report to the TAMC the mileage and condition
of the road and bridge system under their jurisdiction.
Rating Teams:
•
Shall be comprised of one (1) member from the Michigan Department of
Transportation (MDOT), one (1) member from the Regional / Metropolitan
Planning Organization (RPO/MPO) and one (1) member from the Act-51
jurisdiction being rated (County, City/Village).
Training:
•
•
•
•
Pavement Surface Evaluation and Rating (PASER): Anyone who participates in
the annual PASER for paved roads condition data collection of the federal-aid
system and influences the rating activity MUST attend on-site PASER training in the
same year the data collection occurs. This does not discourage observers from
riding in the data collection vehicles for information purposes.
New raters (never attended PASER training before) and seasoned raters (who did
not attend PASER training the year prior) MUST attend one (1) supplemental
PASER webinar training session in addition to attending one (1) on-site session.
Individuals that are PASER Certified Raters are exempted from on-site training as
defined in PASER Certification Eligibility Requirements section of this policy.
Inventory-Based Rating (IBR): Anyone who participates in the annual IBR for
unpaved roads condition data collection of the federal-aid system and influences
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 42
•
•
the rating activity MUST attend on-site IBR training no more than three (3) calendar
years from the data collection occurring. This does not discourage observers from
riding in the data collection vehicles for information purposes.
New raters (never attended IBR training before) and seasoned raters (who did not
attend IBR training more than three (3) calendar years prior) MUST attend one (1)
supplemental IBR webinar training session in addition to attending one (1) on-site
session.
RPO and MPO coordinators are required to attend PASER and IBR on-site training
events every year regardless of their experience or certification status. RPO and
MPO representatives are critical to the success of TAMC PASER/IBR data
collection, so it is important for them to continue to promote and support the
program by attending on-site events.
PASER (paved roads) Certification Eligibility Requirements
To be considered a candidate to take the PASER certification exam the individual must
meet the following criteria:
1) All candidates: Six (6) or more years (not including the current calendar year) of
attendance of TAMC PASER on-site training as verified through the Center for
Technology & Training (CTT) records.
2) Candidates that are civil engineers: five (5) or more years (not including the current
calendar year) of attendance of TAMC PASER on-site training as verified through CTT
records.
3) Rated a portion of their road network during the TAMC collection for the same number
of years trained (not including the current calendar year). This will be verified by a
signed letter from the individual stating their rating experience.
4) Attend the current calendar year TAMC PASER on-site training portion of the workshop
as well as the examination administration portion of the workshop.
PASER Certification Exam
1) The written certification exam will be administered at the on-site sessions of TAMC
PASER training to eligible candidates.
2) Candidates must pass the written certification exam during the on-site training
sessions. The passing score is 70 percent correct or will be adjusted using the normal
distribution (bell curve) of the scores depending on the difficulty of the exam questions
at the discretion of CTT staff.
3) Candidates who do not pass the certification exam will be able to attend another on-site
PASER session during the same year and retake the exam as space and
administration allows. Individuals may repeat examination sessions as many times in
one year as space and administration allows.
4) The TAMC will hold exam results and exam questions as documents that are not open
to the public without a freedom of information act request to prohibit development of
files of exam questions that can be used to memorize facts rather than learning
concepts.
Certification Benefits and Responsibilities for PASER
1) Certified raters are required to attend on-site TAMC PASER training every other year;
i.e. a two (2) year cycle to recertify by taking the certification exam. For example:
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 43
a. Certification Year: Candidate is required to attend the TAMC PASER on-site
training portion of the workshop as well as the exam administration portion. If
the candidate passes the certification exam he/she is certified for that and the
next rating season.
b. One year after Certification Year: The certified individual is not required to
attend the TAMC PASER on-site training portion of the workshop or the exam
administration portion during the calendar year immediately preceding the year
of certification. Certified individuals must attend an organizational webinar.
c. Two years after Certification Year: Recertification - the certified individual is
required to attend the TAMC PASER on-site training portion of the workshop as
well as the exam administration portion to take the exam for recertification.
As data are collected and Quality Assurance/Quality Control verifies that quality data are
being produced, the TAMC may consider decreasing the required training certification
frequency to once every three (3) years for certified individuals.
2) Certified individuals are required to attend an organizational webinar for updates to
business rules and changes to the data collection process. This webinar is required to
keep certified raters informed of new guidance in the program and provides raters with
an opportunity to interact with TAMC members.
Certification for IBR (unpaved roads)
There is no certification yet available for TAMC IBR training for unpaved roads. The TAMC
may consider implementing a certification for IBR that is similar to the TAMC PASER
certification requirements but on a three (3) year cycle.
Data Collection:
•
•
•
•
•
•
The TAMC will annually budget for data collection on:
o 50 percent of the paved federal-aid network.
o 50 percent of the unpaved federal-aid network for the first two years of
collection and then 33.3 percent of the unpaved federal-aid network after the
first two years.
Data collection must be consistent with the PASER collection business rules for
paved roads and with the IBR collection business rules for unpaved roads.
The use of the Roadsoft Laptop Data Collector (LDC) is required.
The first day for field data collection shall be April 1st of every year for paved
roads (PASER).
The data collection for unpaved roads (IBR) shall start any time after January 1st of
every year but shall not be conducted when there is snow on the ground or when
the grass is too high to see the ditch depth.
The last day for field data collection shall be the last Friday in November for
paved and unpaved roads.
Data Submission:
•
•
The RPO/MPO Coordinator is responsible for submitting the completed PASER/IBR
Data export to the Michigan Center for Shared Solutions (CSS).
The deadline for the RPO/MPO to upload data to CSS is the first Friday in
December.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 44
Data Standards:
The export file from Roadsoft will be in a Shapefile format. It is the user's responsibility to
ensure that the correct file type is submitted. Exports containing text files are not accepted.
Instructions on how to prepare the federal-aid road network for the LDC and how to submit
the collected data can be downloaded at the following web site:
*See the current year’s PASER/IBR Training Manual under the PASER Training page at
http://www.ctt.mtu.edu/sites/ctt/files/resources/2015paser/2015-paser-training-manual.pdf
Quality Control:
The Regional/Metropolitan Planning Coordinator MUST review the collected data before
sending it to the Center for Shared Solutions (CSS) looking for missing entries (zeros),
valid surface type, missing surface type, valid number of lanes, missing lane information
and large jumps in PASER/IBR numbers (up/down) in areas where treatments were not
done.
Reimbursement:
Each rating team must complete a Time Expense Log in order to be reimbursed by the
TAMC. These are provided and submitted by the Regional / Metropolitan Planning
Organization Coordinator to the TAMC Asset Management Coordinator.
•
•
•
The team member representing the Act-51 jurisdiction being rated (County,
City/Village) will be reimbursed for relevant expenses related to the data collection
effort (time, travel, meals) via annual RPO/MPO project authorization with the
TAMC.
The team member representing MDOT will be reimbursed by the TAMC via annual
approved budget for PASER/IBR review.
The team member representing the RPO/MPO will be reimbursed via annual project
authorization with the TAMC.
If you have any questions relating to reimbursement and/or this policy as a whole, please
contact:
Frank Kelley – TAMC Asset Management Coordinator
Michigan Department of Transportation
P.O. Box 30050
425 W. Ottawa St.
Lansing, MI 48909
517.373.2111
kelleyf@michigan.gov
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 45
Appendix C: Draft Policy for Collection of Roadway Condition Data
on (Paved and Unpaved) Non-Federal Aid Eligible Roads & Streets
This document is based on the policy adopted by The Transportation Asset Management Council on
February 6, 2013.
To view the policy go to http://tamc.mcgi.state.mi.us/MITRP/Council/Policies.aspx
Introduction:
The Transportation Asset Management Council (TAMC) was established to expand the
practice of asset management statewide to enhance the productivity of investing in
Michigan’s roads and bridges. Part of the TAMC’s mission is to collect physical inventory
and condition data on all roads and bridges in Michigan. This document describes the
policy and procedures for collecting the physical inventory and condition data on the
(paved and unpaved) non-federal aid eligible roads & streets of the State.
The TAMC encourages all Local Road Agencies to annually collect and report the
physical inventory and condition data on their (paved and unpaved) non-federal aid
eligible roads as required by Act 51. The intent of this Policy is two-fold:
1. To provide agencies with guidance on complying with the requirements of Act 51;
2. To establish standards for data collection that allow agencies to be reimbursed
by the TAMC.
Requirements:
According to Act 51 (P.A. 499 2002, P.A. 199 2007); each Local Road Agency and the
Department of Transportation shall annually report to the TAMC the mileage and
condition of the road and bridge system under their jurisdiction and the receipts and
disbursements of road and street funds in the manner prescribed by the TAMC.
To assist agencies with this responsibility, the TAMC will annually budget funds to
reimburse agencies for data collection on up to one-third of the State’s (paved and
unpaved) non- federal aid road system. At the beginning of each year the TAMC will
identify and notify those agencies that are eligible to submit data for reimbursement.
Agencies must certify in writing by the end of the first week of March that they intend to
collect and submit data in the manner established by the TAMC. If following the
certification deadline, funds budgeted for this purpose have not been fully committed; the
TAMC may approve requests from other local agencies for data collection on the (paved
and unpaved) non-federal aid road system.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 46
Written certification to collect data must be sent to:
Frank Kelley – TAMC Asset Management Coordinator
P.O. Box 30050 Lansing, MI
48909
517.373.2111 or;
Email: kelleyf@michigan.gov
Data Collection:
• Data collection must be consistent with the Pavement Surface Evaluation and
Rating (PASER) collection business rules used on the Federal-Aid System for
paved roads and with the Inventory-Based Rating (IBR) collection business rules
used on the Federal-Aid System for unpaved roads.
• The use of the Roadsoft Laptop Data Collector (LDC) is required.
• The first day for field data collection shall be April 1st of each year for paved roads.
• The IBR data collection for unpaved roads shall not be when there is snow on the
ground or when the grass is too high to see the ditch depth.
• The last day for field data collection shall be the last Friday in November of each year
for paved and unpaved roads.
Data Submission:
In order to be eligible for reimbursement, all agencies that participate in this effort will be
required to provide an export shapfile from Roadsoft of the non-federal aid eligible roads and
streets collected. Agencies will be responsible for submitting this Roadsoft export file to their
Regional / Metropolitan Planning Organization (RPO/MPO). The RPO/MPO is responsible for
initial quality control of the export file and to upload to the Michigan Center for Shared
Solutions (CSS), through the Investment Reporting Tool (IRT). The deadline for the
RPO/MPO to upload data to CSS is the first Friday in December.
Data Standards:
The export file from Roadsoft will be in a shapefile format. It is the user's responsibility to
ensure that the correct file type is submitted. Exports containing text files are not accepted.
Instructions on how to prepare the local road network for the LDC and how to submit the
collected data can be downloaded at the following web site:
*See the current year’s PASER/IBR Training Manual under the PASER/IBR Training
page at: http://www.michiganltap.org/PASER&IBR_Manual
Reimbursement:
The TAMC will reimburse each participating Local Road Agency for this effort at a rate as
determined by the TAMC. Agencies will be reimbursed by the TAMC after confirmation has
been received from the CSS that the correct Roadsoft export file has been received. Update
by Coordinator: Invoices must be sent by the agency that did the actual data collection to the
Asset Management Coordinator for reimbursement stating the following:
1. The expense (based on mileage rate) for PASER/IBR collection on
(paved/unpaved) non-federal aid eligible roads and streets (not to exceed the
original certified amount); and
2. The total number of miles rated; and
3. The name(s) of each rater.
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 47
Appendix C: Training Handout
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 48
Inventory Based Rating System for Unpaved Roads, Pilot Data Collection Report Page 49
IBR Pilot Training Slides
Inventory-Based Rating
Training Pilot
Agenda Overview
Inventory-Based Rating (IBR) Pilot and Goals
Pilot Rating Details
Tim Colling, PhD., P.E.
Feature Assessment
John Kiefer, P.E.
Rating Exercises
Pete Torola, P.E.
Why Should We Rate This Road?
Why Use IBR on Gravel Roads?
• Michigan does not currently rate gravel roads
• Gravel roads are half of Michigan’s Non-Fed Aid
network*
(33% of entire Michigan Road Network)
• Three items to measure that don’t change rapidly
• Shows the system’s impact on gravel roads
*Source: Transportation Asset Management Council; Michigan’s Roads & Bridges 2013 Annual Report
Inventory-Based Rating (IBR)
for Unpaved Roads - Report
Professional Review Panel
Travis Bartholomew – RC for Kalamazoo County
John Daily PhD., P.E. – Genesee County RC
Karl Hanson, P.E. – Wexford County RC
Joanna Johnson – RC for Kalam. Co / TAMC
Lance Malburg, P.E. – Dickinson County RC
Bill McEntee – RC for Oakland Co. (retired) / TAMC
Brian Sanada – MDOT
Pat Schafer, P.E. – MDOT
Burt Thompson, P.E. – Antrim County RC
IBR Pilot Training Slides
Why are You Doing the Pilot?
Steps for Implementation
Review/Revise Pilot Field Draft Report
Collection
• User feedback
• Data for local agencies
Revisions to Software
Submit Report for Pilot
Set Policy for Unpaved Collection
2013‐2014
2015
2016
Statewide Training and Collection Start?
2017
What are the Goals of Pilot Ratings?
• Rate 200 - 250 miles per agency
• 1 - 2 days of rating at each agency
• Collect data for Pilot agencies
• Varying characteristics
• UP County
• Northern LP County
• Urban County
• Agricultural County
• Network level rating has never been done
• No definitive assessment of gravel network
Other Unpaved Road Rating Systems
1. Surface distresses are rapidly transient
• Require frequent collection
• Unstable long term network-level
measurement
• Realistic collection rate
• Rater feedback on the system
• Edit training material
• Training and statewide collection
(possibly in 2017)
Other Unpaved Road Rating Systems
Other Unpaved Road Rating Systems
2. Do not consider other road features which have
a major impact on road users
3. Not directly related to the change in value or
usability of the asset
IBR Pilot Training Slides
Goal of the IBR System
Goal of the IBR System
Network level performance metric similar to
asphalt
60
Percent of Lane Miles
50
• Metric that does not change with routine
maintenance
Surface distresses can change quickly
• Rapid collection, low maintenance costs
Systems like PASER need annual collection
40
30
20
• Not necessarily a measure to guide treatment
10
2014_13
2013_12
2012_11
2008
2011_10
2007
2010_09
2006
2009_08
Fair
2014_13
2013_12
2012_11
2008
2011_10
2007
2010_09
2009_08
Good
Chesbro: Transportation Asset Management Council
2006
2014_13
2013_12
2012_11
2011_10
2008
2007
2010_09
2006
2009_08
0
Poor
4 Feb 2015
2015 Pilot Schedule
What Tools Are Used?
Kickoff Meeting has occurred
July to CTT performs onsite training and August rides along during data collection
September Post Collection Focus Group Meeting
October
Final Report of Pilot Roadsoft 7.8
Roadsoft GPS Laptop Data Collector 7.8
With Framework Version 15
LDC export created from CRC network
LDC Unpaved Pilot Mode
Pilot Rating Details
CRC - create network and rate
CTT - Vehicle, computer/GPS, and ride along to
observe
MDOT and Planning Organizations can ride along
to provide feedback
IBR Pilot Training Slides
Concrete Ratings
Dealing With Joint Repairs
Discussion Question:
We told you our goals of the pilot.
What are yours?
What Features are Measured?
How are Features Measured?
Good
• Surface Width
• Drainage Adequacy
• Structure Adequacy
Feature – Width Assessment
• Impacts speeds
• Impacts safety
• Impacts cost of asset
9’
26’
Fair
Poor
Discussion Question:
It is a dead end road leading to one house.
10 feet wide should be Good for them, right?
IBR Pilot Training Slides
Measurable Width
Width is the portion of the road that includes travel
lanes and any shoulder suitable for travel.
Baseline for Width
22’ wide road
At 20 mph a driver does not feel they need to
slow down when approaching another vehicle in
the opposite lane.
22’
1’
Good Surface Width
6’
8’
6’
Vehicle
Space
Vehicle
1’
Fair Surface Width
22 feet wide or greater
16 to 21 feet wide
Vehicles have sufficient room to pass by each
other when approaching in the opposite direction
Vehicles should reduce speed to pass by each
other when traveling in the opposite direction
Reduction of speed is unnecessary
Remedy/Action: 1’ to 6’ of widening
Remedy/Action: None
Poor Surface Width
15’ or less
One vehicle should slow down and pull over.
The other should reduce speed to pass by when
traveling in the opposite direction
Remedy/Action: 7’ to 15’ of widening
Feature – Drainage Assessment
• Impacts condition of surface
• Impacts required routine maintenance frequency
IBR Pilot Training Slides
Good Drainage
Baseline for Drainage
Edge of road has 2’ of separation from water
level under normal conditions
The difference in elevation from the ditch flow
line (or any standing water, whichever is less) to
the top edge of the shoulder is 2’ or more
No secondary ditches are present
2 feet
2 feet
Good Drainage
Remedy/Action: None
Good Drainage
2 feet
or more
Fair Drainage
The difference in elevation from the ditch flow
line (or any standing water, whichever is less) to
the top edge of the shoulder is 2’ or more where
secondary ditches are present.
Or:
The top edge of the shoulder is 2’ to 0.5’ if
secondary ditches are present or not.
Fair Drainage
Remedy/Action: Ditches or swales are present
but they need to be cleaned out and/or remove
secondary ditches.
IBR Pilot Training Slides
Fair Drainage
High Shoulder / Secondary Ditch
Only possible rating is Fair or Poor with secondary
ditches
Additional Guidance
Additional Guidance
Ditch on one side is 2’ or more and between
0.5’ and 2’ on the other
Rate Drainage Fair
No ditch on one side and
Ditch is 2’ or more on the other
Rate Drainage Fair
2’ or more
0.5’ to 2’
2’ or more
Additional Guidance
Additional Guidance
Ditches on both sides are between
0.5’ and 2’
Rate Drainage Fair
Ditches on both sides are 2’ or more and
secondary ditch is causing roadway ponding
Rate Drainage Fair
0.5’ to 2’
2’ or more
IBR Pilot Training Slides
Poor Drainage
Poor Drainage
The difference in elevation from the ditch flow
line (or any standing water, whichever is less) to
the top edge of the shoulder is less than 0.5’
Remedy/Action: Ditches need to be created
Poor Drainage
Additional Guidance
Less than
0.5’
Feature - Structural Assessment
• Structure is a function of:
• Traffic volume and loads
• Material properties and thickness
• Cross section for drainage off the surface
• Construction
• Lack of structure results in structural distresses
• Major potholing that are 3 feet wide or larger
• Ruts that are greater than 1 inch deep
• These are the usual condition triggers for major
work
No ditch on one side and
Less than a two foot ditch on the other:
Rate Drainage Poor
Less than 2’
Traffic Volume and Loads
IBR Pilot Training Slides
Traffic Volume and Loads
Traffic and Excess Moisture
Structural Adequacy
Structural Distress - Rutting
• Impacts condition of surface (speed)
• Impacts required maintenance frequency
• Impacts rehabilitation frequency
Structural Distress - Potholes
> 1”
Baseline for Structure
Greater than 3’
Road has 8 inches of good quality gravel over
the length of the segment
8 inches
IBR Pilot Training Slides
Good Structural Adequacy
Fair Structural Adequacy
History Item
Frequency or Measure
1” Ruts or 3’ Potholes Did not develop throughout
History Item
Frequency or Measure
1” Ruts or 3’ Potholes Apparent during the spring or
Emergency
Was not required
maintenance to make
road passable
8” or more
Existing gravel
thickness
Emergency
Necessary during wet periods
maintenance to make
road passable
Existing gravel
4” to 7”
thickness
the year
Remedy/Action - None
Poor Structural Adequacy
History Item
Frequency or Measure
1” Ruts or 3’ Potholes Apparent during most of the
year
Emergency
Required frequently
maintenance to make throughout the year
road passable
Existing gravel
Less than 4”
thickness
very wet periods
Remedy/Action - Placement of 4 inches of good
quality gravel would be recommended as a fix
(assuming drainage is good).
Adding Gravel Remedies
• The Remedies given are assuming that cross
slope drainage is good
• Look into what is causing structural problems
• The structure may be good but just saturated
• More gravel is not a remedy for bad cross slope
drainage
Remedy/Action - Placement of 5 to 8 inches of
good quality gravel would be recommended as a fix
(assuming drainage is good).
Discussion Question:
There is 8” of existing gravel (Good) but the road
still blows up in the Spring (Fair).
How should this be rated?
Discussion Question:
How do you determine the gravel thickness on
your roads?
IBR Pilot Training Slides
IBR Pilot Data Collection Rules
Discussion Question:
Should you be allowed to rate in the rain?
Rating Rules
Width Rating Rules
• Unpaved roads can be highly variable. Rate the
overall assessment of the segment
• Beware of the perception of a larger width when
there are earth shoulders
• Break up the segment if you have a definitive
change in assessment
• Segments should not be smaller than 0.25 miles
Trees and Slopes Can influence
Perception of Width
• Cast off gravel on an earth shoulder should not
be measured in the surface width
Discussion Question:
How should a road with no crown and bad
segregation be rated using IBR?
IBR Pilot Training Slides
Discussion Question:
Drainage Remedy/Actions
Tip: Gauge the segment by the level of drainage
work that should be done
How do I rate the drainage on the top of a hill
where there are not usually ditches anyway?
Good – None
Fair – Ditches or swales are present and cross
drainage is sufficient but they need to be cleaned
out
Poor – Ditches need to be created
Discussion Question:
How do I rate the Structural Adequacy of a
seasonal road that doesn’t blow up because it
doesn't get traffic?
Discussion Question:
I’m new to the agency and I don’t know the history,
How do I rate Structural Adequacy?
Rating Example
Rutting only during the Fair Structure
Spring
Ditches are over 2’ Good Drainage
deep
Need to pull over to let Poor Width
the neighbor by
Overall Rating of 4 (Poor)
6’ Wheel Path
IBR Pilot Training Slides
What if you add 4 inches of gravel?
Structure ‐ At least 8” Good Structure
of gravel overall
Rate this road….
Width
Good
Drainage
Structure
Good
9
IBR
Drainage ‐
Good Drainage
No Change
Good
> 2’ Ditch
Width ‐
Poor Width
No Change
Overall Rating of 5 (Fair)
Rate this road….
Width
Poor
Rate this road….
Drainage
Poor
Structure
Poor
Width
Fair
1
IBR
Drainage
Fair
> 2’ Ditch on one side
<15’
18’-20’
Rate this road….
Poor
Rate this road….
Drainage
IBR
Poor
Structure
Fair
2
Width
Fair
Drainage
IBR
Poor
Structure
Fair
5
No Ditch
< 16’
Good
7
IBR
No Ditch
Width
Structure
< 0.5’ Ditch
18’
IBR Pilot Training Slides
Rate this road….
Width
Fair
Rate this road….
Drainage
IBR
Good
Structure
Fair
Width
Good
7
>2’ Ditch
Drainage
Fair
Structure
Poor
6
IBR
> 22’
18’
Final Comments
1’ Ditch
Secondary Ditch Starting
Laptop in the Back of the Van!
We need your feedback to make this a successful
pilot!
Questions?
This is a WORK ZONE
Data Collection = Hazards
• Warning light bar
Rate this road….
Width
Good
Drainage
IBR
• Safety garments
• Comply with your work
rules for being in the Rightof-Way
Fair
8
1’ Ditch
> 22’
Structure
Fair
IBR Pilot Training Slides
Rate this road….
Width
Fair
Presenters
Drainage
IBR
Good
Structure
6
Poor
>2’ Ditch
Potholes
Tim Colling, PhD., P.E.
Pete Torola, P.E.
CTT Director
Research Engineer
18’
Stop distractions!
Creating the Unpaved Network
• Target is 200 to 250 miles per agency
• Vary the network
(not just seasonal roads)
• Send your networks to
CTT a week before the
pilot dates
Shaughn Kern
John Kiefer, P.E.
Technical Writer
Research Engineer
TAMC
Good Structural Adequacy
Segment History
Rutting over 1 inch or major potholes** did not
develop throughout the year.
Emergency maintenance was not required
leaving the road passable throughout the year
(when plowed).
Alternately, an estimate of eight inches thick or
more of good existing gravel would qualify a
road for this category.
Remedy/Action - No additional good quality
gravel would be recommended as a fix.
IBR Pilot Training Slides
Fair Structural Adequacy
Poor Structural Adequacy
Segment History
Rutting over 1 inch and/or some major
potholes** are apparent during the spring or very
wet periods.
Segment History
Rutting over 1 inch and/or major potholes** are
apparent during much of the year.
Emergency maintenance grading was necessary
to maintain and make the road passable during
the wet periods.
Frequent emergency maintenance was required
to make the road passable throughout the year.
Alternately, an estimate of four to seven inches
of good existing gravel.
Remedy/Action - Placement of four inches of
good quality gravel would be recommended as a
fix.
Alternately, an estimate of less than four inches,
of good existing gravel.
Remedy/Action - Placement of five to eight
inches of good quality gravel would be
recommended as a fix.