PROPOSAL
Land Development Risk Analysis for the Statewide Mobility System
James H. Lambert, Research Associate Professor and Associate Director
Center for Risk Management of Engineering Systems, University of Virginia
Center for Risk Management of Engineering Systems, University of Virginia
ABSTRACT
This effort will develop and test a model to forecast ten-year land development on the 5,700-mile
Statewide Mobility System. The effort will integrate diverse sources of data in a map-based
approach: population and employment, conservation and preservation and other defined-use
parcels, geometry and terrain, and real-estate transactions. The effort will compare the forecasts
to existing access-point densities. The resulting capability will provide improved awareness for
VDOT of where needed transportation improvements are influenced by land development,
support for VDOT in a process to minimize the impacts of land development to transportation
systems, and support for VDOT in key stages of STIP and SYP processes, and in decisions
related to access management.
BACKGROUND
Chapter 527 of the Code of Virginia (Section 15.2-2222.1) mandates improvements to access
management. The Code calls for a proactive strategy that anticipates land development in order
to negotiate proffers with owners and developers on critical highway sections. The Secretary and
Commissioner are exploring a linking of land-use and transportation planning. VDOT is
publishing its 2035 Surface Transportation Plan in 2009. We believe that Chapter 527 legislation
will be severely limited in its effectiveness without soon achieving: (i) a five-to-ten-year forecast
and action horizon, and (ii) appropriate benchmarking across a statewide system. Current
approaches are ad hoc lacking quantitative methods and based on variable intuition and
knowledge of local jurisdictions. VDOT and VTrans have addressed land use and access
management in corridor analyses with two- and twenty-year horizons, with no current capability
to address the five-to-ten year horizon that is critical.
Chapter 527 also requires localities to submit comprehensive plans and amendments to
comprehensive plans that will substantially affect transportation on state-controlled highways to
the Virginia Department of Transportation (VDOT) in order for the agency to review and
provide comments on the impact of the item submitted. This section also requires localities to
submit traffic impact statements along with proposed rezoning, site plans, and subdivision plats
that will substantially affect transportation on state-controlled highways to VDOT for comments
on the impacts and how they can be mitigated. The Chapter 527 furthermore directs VDOT to
promulgate regulations for the implementation of these requirements. VDOT is working to
establish a comprehensive access management program that includes corridor protection. At
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present, right of way purchases are managed in the project development process of the Six-Year
Program and State Transportation Improvement Program.
PROBLEM STATEMENT
It is critical that planners anticipate future development to avoid surprise, regret, and belated
action. Timely action includes coordination among the state, regions, localities and developers to
identify and protect vulnerable corridor sections for future road, pedestrian and bicycle facilities,
and intermodal facilities.
VDOT is increasingly involved with the land development process along rapidly evolving
transportation corridors. The land development process on transportation corridors involves
preparation of future land use and transportation plan components of the locality comprehensive
plan, rezoning of land, review of site plans for commercial development, review of subdivision
plats for residential development, points of interest, real estate data, public utilities, right of way,
managing access to the corridor, acceptance of new facilities to the statewide secondary system,
and the transportation facilities themselves.
VDOT can provide localities with valuable assistance in understanding how land development
can impact transportation corridors with respect to congestion and traffic crash impacts as well as
to advise them on what measures can be taken to prevent such impacts. However, there can be
impediments to VDOT’s involvement. Localities may have out of date comprehensive plans,
lack proper zoning and subdivision regulations, be unwilling to share their future land use and
transportation plans for developing corridors with VDOT, and may not forward land
development proposals to VDOT to review and advise on the transportation impacts.
There are opportunities for localities to advise land development applicants in the rezoning, site
plan, and subdivision plat approval process of the necessary spacing for entrances to meet access
management regulations. This can avoid developer confusion and resistance to making changes
when VDOT reviews entrance permit applications and to developers requesting exceptions to the
access management entrance spacing standards. PDCs, MPOs, and localities may not be aware of
opportunities to coordinate with VDOT on access management plans for rapidly evolving
transportation corridors so that entrances and signalized intersections can be planned in advance
to prevent/reduce congestion and traffic crashes.
Furthermore, the Secondary Street Acceptance Requirements (SSAR; Virginia Administrative
Code 24VAC30-92-10) approved by the Commonwealth Transportation Board in 2009 require
local governments to provide additional land development planning information to VDOT. The
SSAR includes new requirements for the acceptance of streets into the secondary system of state
highways. Because Virginia is a geographically and socially diverse state, these requirements
vary, based upon the area type within which a development is located. Since some area type
boundaries are based upon local planning boundaries, that information must be provided to
VDOT, which is then required to publish it so that the state’s citizens can determine what type of
area requirements apply to a particular development.
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PURPOSE AND SCOPE
Management of access, defined as the coordination and regulation of entrances and intersections
along a highway corridor, is a proven method of reducing crashes and congestion for the
transportation system as a whole. Yet while VDOT and through travelers receive its benefits, the
costs of good access management are borne by the county and the landowner in the form of time
(e.g., more detailed site plan reviews), land (e.g., sharing of inter-parcel connections among
private properties), and expense (e.g., the construction of supporting facilities such as frontage
roads). It is understandable, therefore, that instances may arise where localities are not willing to
undertake these extra costs.
The purpose of this research is to position VDOT to work with localities to identify such
corridors and to reduce these costs to localities. The research will serve the development of
corridor plans where, as part of the proffer system, developers would fund the construction of a
frontage road in concert with new land development. While land development decisions rest with
the localities, VDOT has an interest in ensuring that localities understand their options for
protecting the Commonwealth’s investment in the roadway network.
Given the aforementioned issues, the scope of this effort is identify for the 5,700-miles Statewide
Mobility System the corridor sections that are most subject to the risk of land development in a
ten-year horizon.
The research hypothesis is that a model integrating diverse sources of currently available data
can forecast land development adjacent to transportation facilities with a ten-year horizon. There
are four significant technical challenges. First, we must identify real-estate transaction data that
is available at the scale of 5,700 centerline miles, recognizing that our past uses of parcel data
from individual jurisdictions will be unwieldy at the larger scale. Preliminary efforts have
suggested particular federal housing and urban development databases and national aerial and
satellite imagery that could be adapted to our purpose. Second, we must synthesize our
knowledge of existing and planned road-access points, facilities, and local zoning. Third, we
must integrate the diverse sources of data with appropriately chosen buffers (1/4 mile, ½ mile, 5mile, etc.) to a single parametric model; we will prototype and test the model in regions prior to
statewide analyses. Fourth, we must ensure in our modeling choices that the developed databases
and methodology are sustainable and transferable to VDOT, involving the GIS Integrator and the
Learning Center, and the regions for their use into the future.
As a corollary, the effort will collect and collate for VDOT several data sources that are relevant
to the acceptance of new secondary roads to the state-maintained system.
METHODS
The effort has the following tasks.
Task 1: Development of predictive model
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We will develop the predictive model combining diverse data of population and employment,
conservation and preservation, facilities and geometries, real-estate transactions, and others.
Task 2: Implementation in selected corridors of the SMS
We will test the model in selected corridors of the SMS. We will coordinate with VDOT to make
a diverse selection of the corridors with respect to length, metropolitan area proximity,
geography and terrain, and status of local access management plans. The steps of this task are:
liaison with the regions and localities along the corridors, data collection, data analysis, and
interpretation of the results with VDOT and the regions.
Task 3: Integration of additional data
We will incorporate several additional map data layers and indicators to the model as
appropriate, including zoning, the linear sequential nature of corridor development, and nonlocally held parcels.
We will characterize the feasibility of identifying existing entrances, crossovers, and traffic
signals, and potential new entrances that meet the access management spacing standards.
Task 4: Collection of data layers in support of land development initiatives and programs
In the course of implementing the model on the SMS highway network, we will assist with the
compilation of local planning boundaries such as town boundaries, growth areas, services
districts, Urban Development Areas, transfer of development rights areas, etc. These geographic
layers have utility and value beyond the corridor risk analysis efforts and will be useful for
VDOT’s long-range planning and land development activities.
Task 5: Materials and reports
We will provide monthly updates to online versions of a training manual for SMS
implementation that includes the lessons learned from our experiences in the previous tasks. The
manual will be clear what are the data needs, what is the needed time, and what are the uses and
benefits.
We will develop materials including slide presentations, a manual, and a research report, provide
telephone support, and otherwise promote adoption of the methodology in various forms as
appropriate for regional organizations throughout the Commonwealth, including the Virginia
Association of Counties and GIS user groups.
We will prepare a prospectus/proposal on this topic for the federal STARS program to further
disseminate the results nationally.
Task 6: Recommendations developed with VDOT and regions
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We will work with VDOT and regional planning organizations to develop recommendations for
data, practices, policies, and procedures of VDOT and regional agencies in support of Chapter
527.
We will develop an annotated flow-chart diagram of the uses by VDOT of the developed
methodology in processes of the STIP and SYP.
Task 7: Technology transfer
We will make presentations to Virginia regions, GIS user groups, and others on-site and via
teleconference with times and locations to be determined in consultation with VDOT and VTRC.
We will coordinate the technology transfer with the VDOT Learning Center and with the VDOT
GIS Integrator.
SCHEDULE
The schedule of the effort is as follows.
Tasks
1.
2.
3.
4.
Development of predictive model
Implementation in selected corridors of the SMS
Integration of additional data
Collection of data layers supporting agency
programs
5. Materials and reports
6. Recommendations developed with VDOT and
regions
7. Technology transfer
Duration Start month End month
(months)
8
11/09
06/10
10
01/10
10/10
4
05/10
08/10
14
11/09
12/10
16
4
11/09
01/11
02/11
04/11
18
11/09
04/11
EXPECTED BENEFITS
The effort provides:

Informing VDOT with a critical five-to-ten-year lead time to protect transportation assets
of the Statewide Mobility System (SMS).

Support for VDOT in key stages of STIP and SYP discussions and decision making
related to access management.

Improved awareness for VDOT of how needed transportation improvements are
influenced by land development,
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
Support for VDOT in a process to minimize the impacts of land development to
transportation systems.

A tool and resource for VDOT and the development community to meet critical mandates
of the Code of Virginia pertaining to access management.

Understanding by VDOT of activities by Virginia localities to identify their urban
development areas by 2011 as required by HB3202.

Perspective of VDOT on regional and local priorities for detailed corridor studies,
specific access management activities, proffers from developers, and improved
subdivision ordinances.

Enhancement of the stature of VDOT in the nation as a leader in the topic of systems
modeling for access management.
The effort is noteworthy for addressing access management in a risk-based process, where we
address through systemic modeling: what are the sources of land-development risk to the
transportation system, what are the relative likelihoods, what are the potential consequences and
horizons, what can be done, what is most effective balancing costs, benefits, and risks, and what
are the impacts of current actions (or inaction) to the future options.
DELIVERABLES
The effort will deliver:
 Implementation of a GIS-based model forecasting land development in a five-to ten-year
horizon for the Statewide Mobility System
 Data collection from federal sources, regions, and localities, becoming a repository of
data for future applications of the model
 Online training manual for VDOT and regions to use the model into the future in
identifying sections of transportation corridor most vulnerable to land development
 Other materials and presentations
 Recommendations for VDOT uses of the developed model for Chapter 527 initiatives and
strategies, and in the processes of the STIP and SYP
 Recommendations for VDOT integration of the model with the GIS Integrator
 VTRC final report documenting the model, data, and its application
 Workshops and trainings with VDOT, localities, VACO, TPRAC, Rural Planning
Managers, GIS user groups, and others
 Documentation of progress through a web site at the University of Virginia.
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Figure 1. New capability for modeling risk of land development supports VDOT in various
activities including STIP, TIP, access management and secondary-system acceptance
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