LINCOLN DEPARTMENT OF TRANSPORTATION
XYZ CORRIDOR
CONCEPT REPORT
MARCH 15, 2007
CURRENT SITUATION AND PROBLEM STATEMENT
The XYZ Corridor (Xavier/Yaloo/Zapeda) is a major commuter route within Lincoln’s Department of Transportation’s
(LDOT) jurisdictional boundaries. The corridor serves as a major link connecting the suburban developments of Yaloo
and Zapeda with Xavier’s commercial/business districts.
The recent housing boom in both Yaloo and Zapeda has resulted in a significant amount of people establishing homes in
the northern portion of the study area and commuting into the city of Zapeda. This shift in origin and destinations has
consequently resulted in congestion and safety problems within the region, particularly during the PM peak period.
The XYZ corridor has experienced congestion and safety problems with the afternoon commute being the most severe.
The traffic data on I-99 and the local arterial indicate multiple points where demand exceeds current capacity. The
current capacity on the highway is estimated at 6,600 vehicles per hour. The freeway is saturated where it intersects
with Penn Street, Lynn Street and Fourth Street. Those interchanges add excessive volume to the northbound Interstate
99. In addition the accident rates are greater at locations near these interchanges. This prompted the Lincoln Department
of Transportation to access possible alternatives to address this problem.
The parallel arterial to I-99 is also experiencing severe congestion. This is primarily at the traffic signals where demand
also exceeds capacity. The intersections at Penn Street, Lynn Street and Fourth Street were again identified as problem
areas. The current signal system has not had any significant timing changes recently. The majority of this arterial is
under the control of Lincoln DOT and as such, would be included in the scope of this study.
VISION AND GOAL
The vision of this study is to improve mobility and safety on the corridor. The goal is to utilize the provided budget to
enhance the operation.
CORRIDOR DESCRIPTION:
The XYZ Corridor is twenty miles long and serves I-99 and Bradley/Gilmore Street. I-99 is a six lane divided limited
access facility and Bradley/Gilmore St. is a four lane divided arterial. The current speed limits along I-99 are 55 mph
and 35 to 45 mph along the arterials. The existing PM peak period volumes along Gilmore/Bradley and I-99 are 2000 &
6000 vph respectively in each direction. Some bus transit service is provided on the arterial. This accounts for one
percent of daily trips.
In regards to accident statistics, the corridor experiences 234 crashes per year with 65% of all crashes occurring within a
½ mile of the existing interchanges. More than half of all incidents are cleared in 30 minutes or less.
From a systems operations perspective, LDOT operates 64 signals on a closed loop system with Xavier utilizing a
centrally controlled system that currently operates independently from the State’s system. Fiber optic cable has been
installed along the freeway and select arterials, but utilization of this utility has been very limited.
LDOT currently maintains a traffic operations center (TOC) for all areas outside of Xavier. At this point the centers
primary functions have been to control the one existing dynamic message system (DMS) along northbound I-99 and
placing messages on the Highway Advisory Radio (HAR). The TOC has the ability to receive inputs from CCTV
cameras along the corridor, but there are currently no devices in place within the study area.
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Freeway Traffic Analysis
Zenn Street
Penn Street
4th Street
Lynn Street
Mainline count
6000
6000
7000
7025
On-ramp count
n/a
1000
25
300
Off-ramp count
n/a
0
0
0
Total count
6000
7000
7025
7325
Gilmore Street Traffic Analysis
Zenn Street
Penn Street
4th Street
Lynn Street
Street count
2000
2000
2100
2500
Cross street turns
n/a
100
400
25
Total count
2000
2100
2500
2525
APPROACH
In order to address the concerns of the XYZ Corridor, an interdisciplinary team of planners, engineers, incident
managers and first responders was formed to identify alternatives and provide recommendations. This team was made
up of experts in the field of Traffic Management, Traveler Information and Incident Management. Prior to working with
LDOT, these individuals worked for the states of Maryland, North Carolina, New York, Massachusetts and Arizona.
There were local government representatives included. This final report documents the findings of this team.
ALTERNATIVES
A number of alternatives were reviewed to address the problems along the XYZ Corridor. These alternatives have been
divided up into those that addressed the freeway, those that addressed the arterial, and those that addressed travel
demand along the entire corridor.
Freeway Alternatives
The following alternatives were reviewed to address the problems on the freeway:



Freeway Service Patrol – Service patrols could be utilized to assist stranded motorist and to provide traffic
control during incidents. The use of these freeway patrols would reduce the impacts of crashes and would
reduce secondary accidents. Given current constraints on hiring, the freeway service patrol would be provided
through an LDOT contract.
Traffic Operation Center – Personnel at the TOC could provide real time traffic management and incident
support. The tools could be operated from the TOC. The TOC would be operated out of an existing state
facility, but there should be links to the City of Xavier traffic signal system. Given current constraints in
staffing, the operators for the Traffic Operation Center would come from LDOT contracts. This solution would
require two operators, twelve hours per day, for five days per week.
Inter-agency integration – there is a need for local and state agencies to better coordinate during incidents.
There is a need for better exchange of information between the two agencies. This could be addressed through a
very simple text messaging system.
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







Closed Circuit TV – Another option that was considered was the use of cameras to monitor conditions on the
freeways and arterials. This could reduce response times for incidents and provide better information on
conditions.
Toll Roads – toll roads could be constructed to provide additional capacity, but given the limitation that no
additional capacity could be built in the near term, this option was not considered further.
Highway Advisory Radio – HAR is currently deployed through out the corridor. Consideration was given to
better utilizing this system through traffic management.
Dynamic Message Signs – there is currently one DMS on the freeway. One option that was considered was to
add additional DMS to inform motorist of road conditions and to shift traffic from the freeway to the arterials
when incidents occur.
Sensors – Another option was to install sensors in the pavement or edge of the roadway to provide traffic counts
and assist in incident detection.
800 MHz radio system – interoperability is a problem. A two-way radio system could enhance
communication.
Corridor Management Team – an interagency team could be developed to look at current management issues
along the corridor. This team would be made up of city, county, state, and federal officials as well as
representatives of the private sector, law enforcement and the planning organizations.
High Occupancy Vehicle Lanes – HOV lanes could provide additional capacity and could reduce the number
of vehicles on the roadway by encouraging people to carpool. The current direction is that no additional
capacity could be built in the near term, so this option was not considered any further.
Arterial Alternatives
The following alternatives were considered to address the problems on the arterials:




800 MHz radio system – interoperability is a problem for incident management on the arterials. A two-way
radio system would enhance communication.
Arterial Dynamic Message Signs – small arterial message signs could be utilized to provide information to
drivers on the current conditions of the arterial roadways.
Traffic signal timing and transit signal priority– the current signals have not been updated recently.
Previous changes in traffic flow dictate that the signal should be retimed. It is recommended that a total of 79
signals be retimed. This includes 64 signals within LDOT’s jurisdiction and 15 within the City of Xavier. This
has a high potential to improve operations along the arterial street. Transit priority should be considered on
selected intersections.
Integrating signal systems – Another option that was considered was to integrate the existing LDOT signal
system into the Xavier signals. This would involve software enhancements and a centralized master server to
provide communication and monitoring of the existing signals.
Demand Management Alternatives
The following alternatives were considered to address the amount of demand on the corridor:



Traveler Information – the goal of this alternative would be to provide real time, accurate information on the
transportation system. Commuters would be able to make better informed decisions about mode and routes.
Traveler information could be used to shift drivers from one route to another and could encourage the use of
buses or car-pool.
Telecommuting – public sector agencies and private sector employers could be encouraged to provide
opportunities for their employees to work from home. This would directly reduce the traffic demand.
Transit utilization – current transit utilization is about 1%. It is recommended that the demand management
strategies include encouraging additional use of the transit system.
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



Flex-time – drivers could be encouraged to change their work hours so they are not commuting during peak
periods. Employers could also have employees work 4/10’s or 9/80’s so that it would reduce the number of
commuters.
Carpooling – a program could be implemented to encourage drivers to share rides. This program could
improve traffic conditions, air quality and fuel conservation.
Park and ride - locations could be identified for park and ride facilities. Agreements would need to be secured
to utilize the locations and proper signage and security features would need to be implemented.
Public information and media outreach – A key consideration of this plan was to provide outreach and
education to the public. It is suggested that professionals in the field be brought in to develop a plan and create
materials for this outreach program. In order for the other options to be effective, it is important that the public
be provided quality information.
COST/BENEFIT ANALYSIS
Freeway Cost/benefits
Freeway Strategies
Ramp Metering
CCTV
HAR
Sensors
DMS
Incident Management (Contract)
Incident Management System
- FSP text message/digital photo back to
TOC
800 Mhz (Communication System)
TOC Coordination
- Integration into existing
-Text message to all agencies
- Operators (contract)
Corridor Management Team
Total Cost of Freeway Strategies
Ops & Maint
Costs
Initial Costs
$80,000
$250,000
$400,000
$1,500,000
$100,000
$500,000
$2,830,000
$8,000
$25,000
$0
$40,000
$150,000
$0
$0
incrSpeed
reducIncDur
reducDelay
reducDelay
Benefit
Mobility Safety
24%
33%
4.50%
5%
0.50%
30%
$0
$10,000
$50,000
$0
$0
$457,600
$0
$740,600
Arterial Cost /benefits
Arterial Strategies
Arterial Dynamic Message Signs
Signal Retiming/ transit priority
Integrated signal system
Total for Arterial Solutions
Ops &
Maint
Costs
Initial
Costs
$500,000
$300,000
$200,000
$1,000,000
4
$50,000
$30,000
$20,000
$100,000
Benefit
Mobility Safety
10%
Travel Demand Cost /benefits
Initial
Travel Demand Strategies
Costs
Demand Management Plan
$100,000
- Telecommunicating, Flex Time, Carpooling, Park & Ride
Public Info Media
$300,000
Total for Travel Demand Solutions
$400,000
Ops &
Maint
Costs
$10,000
$0
$30,000
$40,000
Benefit
RECOMMENDATIONS
Based on an analysis of the costs and benefits, the team recommends that the freeway congestion be addressed through
ramp metering, freeway management, and incident management. This would include installing cameras, sensor, and
dynamic message signs for managing freeways. It would also include freeway service patrol. The team also
recommends provide freeway service patrol to address stranded motorist. A Traffic Operation Center should also be
implemented to provide a central location for managing the system.
It is recommended that the arterial system be improved through retiming of the signals and linking the multiple signals
together. It is also recommended that a few message signs be placed on the arterial system.
Finally, it is recommended that aggressive travel demand activities be undertaken to reduce the demand on the system.
This includes telecommuting, flexible work weeks, carpooling, transit, and park and rides. It is further recommended
that a public outreach campaign be performed to educate the public on this program.
System
Components
Ramp Metering
Freeway Management
Meters
Cameras
Highway Advisory Radio
Sensors
Dynamic Message Signs
Freeway Service Patrol
Radio system
Traffic Operation Center
Incident Management
Corridor Management Team
Arterial Management
Demand Management
Arterial Dynamic Message Signs
Signal Retiming
Integrated Signal Systems
Demand Management Plan
Public Information Campaign
It is estimated that the freeway solutions would cost approximately $3m. The arterial solution would cost about $1M
and the travel demand solutions would cost another $.5M In addition another $.5M should be set aside for design and
contingencies.
The operational costs are expected to increase by about $1M per year.
The next step is to provide a recommendation to the management of LDOT and the local stakeholders. If this plan is
adopted then a full systems engineering analyses should be completed in order to insure that this program has a high
probability of success. It is recommended that an implementation plan be developed to guide the project.
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APPENDIX A
In order to better assess the alternatives for this study, the team drafted a high level concept of operation.
Concept of operations
Conditions of surface transportation impact roadway safety, mobility, and productivity. Adverse road conditions due to
congestion, work zones, crashes, special events, and weather, impact mobility by increasing travel time delay, reduce
throughput and speeds, and increase speed variance. Such events influence productivity by disrupting access to road
networks, and increasing road operating and maintenance costs.
Participating Agencies Roles and Responsibilities
The ITS Elements of XYZ localities and LDOT’s Field Equipment (DMS, CCTV, Sensors, Ramp metering, Traffic
signal timing, Portable DMS and communication backbone), the equipment would be entirely operated and managed by
LDOT. Under this project, additional field equipment would be integrated into the existing TOC. Signal control would
be under the existing local agency control management; however traffic responsive system integrated with the corridor
management would be supervised by LDOT.
Three types of travel management strategies would be employed in response to such adverse conditions: advisory,
control, and response strategies. Advisory strategies provide information on prevailing and predicted conditions to both
the LDOT TOC and the motorists. Control strategies alter the state of roadway devices to permit or restrict traffic flow
and regulate roadway capacity. Response strategies supply resources to minimize or mitigate impacts.
Travel time is one of the most important pieces of information that could be given to motorists. It is exactly the
information they want, need, and can easily interpret and tailor to their specific trips. The approach that would be used
for this project would be based on point detection and CCTVs. The TOC would make en-route travel times available to
the public via dynamic message signs (DMS's). Travel time or delay information would typically be given by
destinations or roadway segments.
Incident Management improvement, integration of law enforcement and LDOT TOC XYZ localities personnel and with
a corridor coalition is of utmost importance in promoting interagency coordination and cooperation and in facilitating
efficiency in incident and traffic management operations. It allows the LDOT TOC, XYZ cities and PD to share
resources more efficiently.
Performance, utilization, and effectiveness of the system would be measured through “before and after study” to assess
the following
1.
2.
3.
Reduction in travel time.
Reduction in incidents and clearance time
Improvement in planning for system operation
The TOC would be operated by LDOT. Data would be shared among cities DOT, State and PD.
Analysis of Alternate System Configurations and Technology Options
As this project is an expansion and upgrade of the ITS systems for freeway management including incident management
along other cities and state highway, a number of technology choices, communications, and technical design of the ITS
implementation would be inherited from the existing implementation. This includes:
1.
Functional compatibility of new ITS field equipment with existing sign technologies, cameras, and
vehicle sensors, and the communications with field elements.
2.
utilize existing communications including fiber optic network is built back to TOC,
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Procurement Options
The implementation of ITS system along the I99 would be an LDOT funded project and would be identified in the
region’s Transportation Improvement Program. The design, specification, development and procurement documents
would follow LDOT’s contract administration procedures. This would include development of plans, specifications and
estimates (PS&E) for the project prior to bid.
System Integration and Life Cycle Costs
Based on a preliminary engineering estimate developed by the LDOT, the total project cost and system integration cost
were identified. The operation and maintenance annual costs were developed from information in the US DOT’s ITS
Cost Benefits database.
Operations and Maintenance
Operations and maintenance annual cost for the field components and communications is estimated at $ 1 million. The
O&M cost is based on 8% of the total project cost
Requirements Definition
The functional requirements defined in this Project Systems Engineering Analysis were derived from the information
maintained in the LDOT Regional Architecture. Requirements for three ITS elements are defined below, as follows:
System
Freeway Management System
Sub Systems
Incident Management

Field Equipment (CCTV and sensors, )

Field Equipment (DMS)

Computerized Incident notification

First responder trucks

etc
Public Advisory

Field Equipment ( Ramp metering and Signals)
TOC (Information and control)
Process Specification – Ramp metering, Sensor, Signals
This process shall control Ramps at the I99. It shall address device control and processes that are responsible for
freeway management.
Process Specification – Provide Traffic Operations Personnel Traffic Data Interface (ID: 1.1.4.2)
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This process shall provide the interface through which traffic operations personnel can obtain access traffic data, traffic
video images, and weather information. This stored data shall comprise current and long term (historic) data on traffic
conditions, and roadside equipment activity. The data shall apply to some or all of the freeways, surface street, and rural
roadways served by the central system. Where appropriate and/or requested by the traffic operations personnel, the
process shall provide the data output in the form of an overlay onto a map of the relevant part(s) of the freeways, surface
street and rural roadways served by the instance of the function.
Equipment Package – TOC Traffic Information Dissemination
This Equipment package provides the capability to disseminate roadway condition information to travelers, potential
travelers, and private information service providers.
This process shall transfer data to processes responsible for controlling roadway information devices such as dynamic
message signs (DMS).
Applicable ITS Standards and Testing Procedures
Selection of Applicable ITS Standards
Based on an analysis of the architecture flows and market package selections for the project, the LDOT ITS
Improvements I99 project would identify the ITS standards and test procedures. The table below shows the applicable
NTCIP center to field communications standards. For the ITS Improvement project. The ITS Improvement project
would not specify NTCIP standards for other ITS devices based on the following considerations:
1. Adding NTCIP communications for CCTV and sensors would require modification to the central software. The
existing central software currently controls cameras based on a proprietary protocol. In order to integrate
NTCIP compliant cameras, the central software would need to be modified to use the SNMP (Simple Network
Management Protocol), as defined by NTCIP as the transport of objects to/from ITS devices.
2. LDOT would need to develop a MIB (Management Information Base), as defined by the NTCIP, as the method
of specifying device object definitions for the various devices The following summarizes the minimum
necessary actions to develop the necessary project-specific NTCIP device object (specifications) for the CCTV
and sensor devices:
a. Develop an operational concept and requirements for the devices.
b. Develop an NTCIP MIB for each of the device types that is conformant with LDOT’s operational
concept and requirements, and the NTCIP conformance statement.
c. Develop performance requirements for communications between the central system and devices
List of Applicable ITS Communications Standards
Document Number
NTCIP 1101
NTCIP 1201
NTCIP 1203
Document Title Involved
Simple Transportation Management Framework (STMF)
Global Object Definitions
Object Definitions for Dynamic Message Signs
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