Moving Ahead for Progress in the 21st Century (MAP-21), the new U.S. federal transportation law, has the following main goals:
These goals are limited and could lead to planning decisions that reduce overall transport system efficiency, depending on how they are interpreted and measured. For example, there are no references to social equity objectives such as improved mobility for non-drivers or increased affordability (i.e., costs as a share of budgets for lower-income households), nor public fitness and health objectives (i.e., increasing walking and cycling activity); congestion reduction is triple counted (congestion reduction, system reliability, and freight movement); and if impacts are measured using conventional metrics, such as roadway level-of-service and crash rates per vehicle-mile, the additional economic, social and environmental costs caused by induced vehicle travel and sprawl will be overlooked, as will many of the benefits of transportation demand management and smart growth policies.
MAP-21 emphasizes performance-based planning. This is good if done correctly. It means that transport planning decisions are based on their ability to achieve specific objectives such as congestion reduction and improved safety, and so tends to support innovative strategies such as transportation demand management, that do not fit into traditional funding categories. For example, congestion pricing, complete streets, smart growth development policies, and parking management strategies can all help increase transport system efficiency, but are poorly supported by conventional transport planning practices.
The effectiveness of this type of planning depends on the specific methods used to measure transport system performance. Conventional transport planning tends to use mobility-based indicators such as roadway level-of-service and the Travel Time Index. As discussed in my recent blog, Toward More Comprehensive Understanding of Traffic Congestion, these are inadequate for evaluating overall transport system performance because:
This is not to deny that traffic congestion imposes significant costs on society by imposing travel delay and increasing fuel consumption and pollution emissions. But even using the relatively high estimates published by the Texas Transportation Institute, which I believe are exaggerated, congestion costs are moderate overall, less than some other transportation costs such as vehicle ownership, vehicle operation, roadway costs, parking facility costs and accident damages. As a result, it would not be cost effective to implement congestion reduction strategies that significantly increase those costs, for example, by requiring motorists to purchase special vehicles for urban commuting or if they increase accident risks, but congestion reduction strategies become much more cost effective if they help achieve other planning objectives such as parking cost savings, consumer savings or improved mobility of non-drivers.
The U.S. Department of Transportation is currently developing performance indicators, and is soliciting public comments through "listening sessions," including one scheduled for this coming Thursday, 25 October 2012, from 1:00 PM to 3:30 PM EDT. This is an opportunity for practitioners to contribute to policy decisions that will have major impacts on our future planning activities.
Here are my suggestions for more comprehensive transport system performance evaluation.
1. Consider the following impacts:
2. Evaluate impacts based on per capita annual costs rather than impacts per unit of travel. For example, evaluate congestion based on per capita annual congestion costs rather than roadway level-of-service, the Travel Time Index, or congestion costs per motorist so this cost can be compared with other impacts such as per capita consumer costs, road and parking facility costs, accident costs, and pollution costs.
What do you think? Are these criticisms and suggestions appropriate? What impacts and indicators do you recommend transportation agencies use to evaluate transport system performance?
For more information
Philip Barham, Samantha Jones and Maja van der Voet (2012), State Of The Art Of Urban Mobility Assessment, Quality management tool for Urban Energy efficient Sustainable Transport (QUEST), Executive Agency for Competitiveness and Innovation, European Commission.
Robert L. Bertini (2005), You Are the Traffic Jam: An Examination of Congestion Measures, Department of Civil & Environmental Engineering, Portland State University, presented at the Transportation Research Board Annual Meeting.
Daniel Bongardt, Dominik Schmid, Cornie Huizenga and Todd Litman (2011), Sustainable Transport Evaluation: Developing Practical Tools for Evaluation in the Context of the CSD Process, Commission on Sustainable Development, United Nations Department Of Economic And Social Affairs.
Joe Cortright (2010), Driven Apart: How Sprawl is Lengthening Our Commutes and Why Misleading Mobility Measures are Making Things Worse, CEOs for Cities (www.ceosforcities.org).
DfT (2006), Transport Analysis Guidance, Integrated Transport Economics and Appraisal, Department for Transport.
Richard Dowling, et al. (2008), Multimodal Level Of Service Analysis For Urban Streets, NCHRP Report 616, Transportation Research Board.
Eric Dumbaugh (2012), Rethinking the Economics of Traffic Congestion, Atlantic Cities, 1 June 2012.
FHWA (2012), Performance Management Overview, U.S. Federal Highway Administration.
J. Richard Kuzmyak (2012), Land Use and Traffic Congestion, Report 618, Arizona Department of Transportation.
John N. LaPlante (2007), "Strategies for Addressing Congestion," ITE Journal, Vol. 77, No. 7, pp. 20-22.
Todd Litman (2003), "Measuring Transportation: Traffic, Mobility and Accessibility," ITE Journal, Vol. 73, No. 10, October, pp. 28-32.
Todd Litman (2005), Well Measured: Developing Indicators for Comprehensive and Sustainable Transport Planning, Victoria Transport Policy Institute; summarized in "Developing Indicators For Comprehensive And Sustainable Transport Planning," Transportation Research Record 2017, TRB, 2007, pp. 10-15.
Todd Litman (2012), Smart Congestion Relief: Comprehensive Analysis Of Traffic Congestion Costs and Congestion Reduction Benefits, presented at the Transportation Research Board Annual Meeting.
WSDOT (2008), Performance Measurement Library, Washington State Department of Transportation.