Number 23 September 1998
New Urban Rail in America: Engineering News Record Invited Rail Commentary by Wendell Cox
A number of US urban areas have built, are building or plan to build new urban rail (light rail or
metro) systems. Public support for these projects is largely based upon the expectation that the
new rail systems will materially alleviate traffic congestion. This is not the case.
Traffic volumes are growing in all US metropolitan areas. An often used measure of traffic
congestion is the Federal Highway Administration/Texas Transportation Institute Roadway
Congestion Index (RCI). Since 1982, traffic congestion has grown from 18 percent to 55 percent
in the metropolitan areas that have built or expanded rail systems (Table #1).(1) Traffic congestion
has risen more rapidly in new rail metropolitan areas than in areas that did not open rail systems
(Figure #1).(2)
The transit ridership increases (including those attributable to rail), that have occurred in the new rail cities have had no material impact on traffic congestion. It is estimated that the Roadway Congestion Index has been reduced in only one(3) of the new rail urban areas, Washington, and there by only 1.5 percent, from 1.43 to 1.45 if the new transit riders had instead traveled by automobile (Figure #2 and Table #2).(4)
This is reflective of one of transit's fundamental problems --- that its market share is so small
that significant ridership increases do virtually nothing to reduce traffic congestion.(6)
1. Texas Transportation Institute, Texas A&M University. 2. Calculated from Texas Transportation Institute data. 3. Denver's system operated for only part of 1994. If the 1995 ridership is used instead (with a full year of rail operation), the impact on the Roadway Congestion Index would be approximately 0.1 percent. This would not change the Roadway Congestion Index. 4. Assumes new transit ridership would have otherwise have been in automobiles at average occupancy and that 12.9 percent of ridership was induced (new), based upon industry research. This new traffic (vehicle miles traveled) was added to the existing level of arterial and freeway traffic and the TTI Roadway Congestion Index recalculated assuming the higher traffic levels. Where transit ridership declined, the Roadway Congestion Index was not changed. Buffalo Roadway Congestion Index is author's estimate. If the 1981 San Diego data is used (pre-rail) the transit impact on the Roadway Congestion Index would be 0.2 percent instead of 0.1 percent --- insufficient to change the 1994 San Diego Roadway Congestion Index. 5. Jonathan E. D. Richmond, New Rail Transit Investments --- A Review (Cambridge, MA: John F. Kennedy School of Government, Harvard University), 1998, p. 95. 6. This finding is considerably different than that of a 1997 transit industry sponsored study, which concluded that transit ridership was so significant that major expansions of freeway systems would be necessary without it (Donald H. Camph, "Dollars and Sense: The Economic Case for Public Transportation in America," Campaign for Efficient Passenger Transportation, 1997)
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