NCHRP 08-36: Research for The AASHTO Standing Committee on Planning
2009-08
I – PROBLEM TITLE: Assessment of Analysis Tools and Models for Effective Land
Use and Transportation Scenario Planning
Submitted by Leslie Snow, CalTrans
II – RESEARCH PROBLEM STATEMENT
A Federal Highways Administration (FHWA) website defines scenario planning as "a process in
which transportation professionals and citizens work together to analyze and shape the long-term
future of their communities. Using a variety of tools and techniques, participants assess trends in
key factors such as transportation, land use, demographics, health, etc. Participants bring the
factors together in alternative future scenarios, each of these reflecting different trend assumptions
and tradeoff preferences." 1 Scenario planning often includes identification and consideration of
Smart Growth, New Urbanist, Neo-traditional, and Sustainable land use and transportation
strategies, such as: concentrating development within existing urban areas, creating a mix of
complementary land uses, clustering uses within walking distance of transit services, and
implementing site design features to facilitate pedestrian, bicycle, and transit travel.
Effective scenario planning involves providing participants reliable estimates of the potential
impacts and benefits of various potential alternatives that are under consideration. To do so, it is
necessary to implement appropriate analytical tools and models can adequately estimate
relationships between a variety of land use, transportation, economic, social, and environmental
strategies. A TRB study recently concluded that four-step traffic models are not suitable for
analyzing mixed-use, pedestrian-based, and/or transit-oriented development scenarios.2 And a
recent study published by the California Department of Transportation3 found that standard travel
demand models typically used in transportation planning are not adequately sensitive to smart
growth strategies. Therefore, such methods may not be appropriate to assess the potential benefits,
estimate impacts, size infrastructure, or develop appropriate mitigations for smart growth land use
and transportation scenarios being considered as part of regional and/or statewide plans.
A variety of analysis and visualization tools (e.g., I-PLACE3S, EPA’s Smart Index), traditional
travel demand, as well as newer advanced models (e.g., activity-based and integrated land
use/economic/transportation models) are being used by some MPOs and DOTs in the U.S. as part
of scenario planning efforts. However, there is currently very little consolidated information
regarding which of these types of tools or models is optimal in various situations and at different
geographic scales, the types of analyses each can perform, their relative costs, data and other
resources needed to effectively implement them, and/or the types of output that each can provide.
III – Objective
This effort will identify, assess, and summarize available analysis tools and models used in
scenario planning efforts and provide examples. It will also produce practical and clear
recommendations regarding “best practices” for selecting and implementing various types of tools,
models, or other methodologies to estimate economic, social, and environmental impacts and
benefits associated with the location, design, densities, and configurations of land uses along with
a variety of multi-modal transportation strategies. It will also assess which tools are appropriate in
various geographic scales (city, regional, statewide) and types of area (e.g., urban, suburban, rural).
1
http://www.fhwa.dot.gov/planning/scenplan/fascenplanrpt.htm
TRB, Metropolitan Travel Forecasting, Current Practice and Future Direction, Special Report 288, 3007, cited in
“CEQA and New Urbanist Development” Cindy van Empel (MA, AICP), Environmental Monitor, Winter 2008.
3
”Assessment of Local Models and Tools for Analyzing Smart-Growth Strategies” – DKS & professors at UCs Irvine &
Santa Barbara, July 2007. http://www.dot.ca.gov/newtech/researchreports/reports/2007/local_models_tools.pdf
2
NCHRP 08-36: Research for The AASHTO Standing Committee on Planning
2009-08
IX – Estimated cost: $100,000. Time Required: one year