Congestion Costing Critique: Critical Evaluation of the “Urban Mobility Report”

The Urban Mobility Report (UMR) is a widely-cited study that quantifies and monetizes (measures in monetary units) traffic congestion costs in U.S. metropolitan regions. This report critically examines the UMR's assumptions and methods. The UMR reflects an older planning paradigm which assumes that " transportation " means automobile travel, and so evaluates transport system performance based primarily on automobile travel speeds. A new planning paradigm is more comprehensive and multi-modal. The UMR methodology tends to overestimate congestion costs and roadway expansion benefits by using higher baseline speeds and travel time unit cost values than most experts recommend; its estimates represent upper-bound values and are two-to four times higher than estimates using more realistic assumptions. It claims that congestion costs are " massive, " although they increase total travel time and fuel consumption costs by 2% at most. It exaggerates roadway expansion benefits by ignoring induced travel impacts and using an inaccurate speed-emission curve. It exaggerates future congestion problems by ignoring evidence of peaking vehicle travel and changing travel demands. The UMR ignores basic research principles: it fails to identify best current practices, explain assumptions, document sources, incorporate peer review, or respond to criticisms.  The UMR is produced by the Texas Transportation Institute with funding from the USDOT's University Transportation Center Program and other government agencies.  The UMR's costing methods do not reflect best current practices recommended by economists.  The UMR tends to overestimate congestion costs and roadway expansion benefits.  Congestion is a modest cost overall, increasing total travel time and fuel costs at most 2%.  The UMR ignores standard research principles such as providing context, explaining assumptions, citing sources, indicating potential sources of bias, and acknowledging legitimate criticisms. Introduction Traffic congestion refers to incremental costs resulting from interference among road users that reduces traffic speeds, and increases driver stress, vehicle operating costs and pollution emission rates. Traffic congestion is nearly universally disliked. There are important and interesting debates concerning how to define and measure congestion, and how to evaluate potential congestion reduction strategies.