Number 35 - March 2000
Light Rail and Traffic Congestion:
You have probably heard that light rail can move the equivalent of six to twelve lanes of freeway passenger volume. Just a few minutes ago, Mr. Snoble indicated that DART would be able to move three freeway lanes of volume on the new Richardson-Plano light rail line. This is, however, misleading. In fact, none of the nation's new light rail lines carries more than 40 percent of a single freeway lane's volume, and usually fewer than 25 percent of the riders are people who would otherwise be driving.
Moreover, light rail and transit are downtown-only solutions. There are no corridors in the United States in which transit carries a significant share of travel that are not downtown corridors. This experience includes Dallas-Fort Worth, New York and most other metropolitan centers. This occurs because it is only to downtown destinations that transit is able to provide the quick, no-transfer express service that can compete with automobile trips. People are not going to switch to transit if it means transferring and thus much longer travel times. Therefore, there is no point in anticipating that any form of transit is capable of relieving the congestion along a non-downtown oriented corridor such as the LBJ Freeway (I-635). Moreover, it is important to understand that downtowns contain only a small portion of metropolitan employment --- downtown Dallas represents less than six percent of employment in the Metroplex, and all of the projections indicate that downtowns will contain an even smaller share of employment in the future.
The point is that light rail has been demonstrated to be incapable of materially reducing traffic volumes in downtown oriented corridors. Light rail has even less potential in non- downtown oriented corridors. Because it does not reduce traffic congestion, it also has little, if any impact on air pollution.