Reason Foundation
Mobility Project

Traffic Congestion in America's Cities

How bad will traffic congestion be in 2030? How much construction and how many new lane miles will each state and major city need to add over the next 25 years to prevent severe congestion? And how much will it all cost? The Reason Foundation study Building Roads to Reduce Traffic Congestion in America's Cities: How Much and at What Cost? and its addendum, A Detailed State-by-State Analysis of Future Congestion and Capacity Needs, provide in-depth answers to these questions.


The Most Congested Cities in 2030

Metropolitan areas on this map are ranked from most congested to least congested, based on their projected Travel Time Indices (TTI) in 2030.

TTI is defined as the ratio of travel time in peak hours to the travel time in off-peak hours. For instance, an index of 1.5 means that travel time in the peak hour is 50 percent longer than in the off-peak.

For more information about a city, click its numbered marker on the map, or click on the list on the right of this page. Use controls in the upper left of map to pan and zoom.

(Click here for a map of congestion by state in 2030)

==> Cities with TTIs that exceed present-day Los Angeles (greater than 1.75)

==> Cities with TTIs that exceed present-day Chicago (greater than 1.57)

Numbers on map represent the city ranking.
(1 = most congested)

Source of data: Reason Foundation, Building Roads to Reduce Traffic Congestion in America's Cities: How Much and at What Cost? by David T. Hartgen and M. Gregory Fields. Project Director, Robert W. Poole.


Cities ranked by traffic congestion projected in 2030. Click to view details.