2009 APTA - TRB Light Rail Conference Issue
 

A new era of U.S. transit development began in 1981 when San Diego, a city that until then operated only buses, opened its first regional Light Rail Transit (LRT) line. Since then, 11 other bus-only metropolitan areas in the U.S. launched their own LRT lines, and many of the original LRT lines have grown and multiplied.

Several of the expanding LRT systems now are the backbones of metropolitan transit networks, carrying a large share of the region’s total transit ridership. In five mid-sized urban regions—San Diego; Portland, OR; Dallas; Sacramento; and Salt Lake City—two to four light rail lines now carry more than 30 percent of transit passenger miles riding on all transit modes in their respective areas. In the cases of San Diego, Sacramento, and Salt Lake City, light rail’s share of total regional transit passenger miles hovers around 50 percent.

Portland and San Diego, the regions with the largest and most integrated bus and light rail networks, have seen both their per-capita ridership and their total transit productivity improve over the past 30 years, while their real operating costs per passenger mile have declined substantially in Portland and risen by only 16 percent in San Diego. The combined bus and light rail networks of these two regions outperform all the bus-only transit systems serving similar-sized U.S. areas.

Shared Attributes
The transit systems in Portland and San Diego share several system attributes that appear to contribute to their success. Both have dispersed transit networks structured to serve an array of major destinations throughout the entire metropolitan area, as opposed to concentrating service in a single major destination, usually the Central Business District (CBD), and/or serving only a portion of the metro area.

Both regions also use LRT to provide a high-speed, intermediate capacity regional service overlay atop the local bus system. In other words, light rail offers higher-speed, higher-frequency service that enables travelers to move quickly and reach the wide array of major destinations throughout the area.

In both Portland and San Diego, the regional light rail lines operate at scheduled speeds about twice as fast as local buses, and typically operating at 15-minute headways. The light rail vehicles, with up to eight units, have much higher capacity than buses, which operate as single units.

Passengers boarding or alighting from light rail trains have many wide doors from which to choose; they do not have to file past the driver single file to pay their fares. This feature, made possible with self-service fare systems, enables large passenger volumes to use the system without slowing down service.

Light rail replaced express bus service in both San Diego and Portland, and the buses continue to operate in corridors not served by light rail. In general, ridership is much higher on light rail than it was on either the express buses that formerly operated in the light rail corridors or the buses that continue to operate.

In San Diego, for example, Express Bus 100—which operated on Interstate 5 before the opening of the South Bay light rail line parallel to the freeway—carried fewer than 1,000 passengers per day. The light rail line provided 11,000 rides per day when it opened and, according to 2006 data, now provides more than 60,000 daily rides.

Express buses serving the employment-rich Interstate 15 corridor, extending north from San Diego, carry only about 5,000 passengers per day. In contrast, the region’s light rail corridors provide 25,000 to 60,000 daily rides, including one that does not serve the CBD.

One reason why express buses carry so many fewer passengers may be the difficulty of integrating them into local bus networks, whereas integration is easy to do with light rail. The only way to make express buses move faster is to operate them along freeways non-stop to the CBD, but such service provides insignificant accessibility to jobs. Having express buses serve intermediate stops where they can provide transfers with local buses requires them to leave the freeway, stop, and then reenter the freeway, adding up to 10 minutes in travel time for each stop.

Another characteristic shared by Portland and San Diego is the cities’ emphasis on easy transfers between their bus and rail systems, as well as bus-to-bus transfers, to connect more destinations than would be possible with a system based on one-seat rides. Transfers provide important evidence that passengers are taking advantage of integrated regional bus-rail transit systems to reach a wide array of regional destinations.

As a result of these design characteristics, the Portland and San Diego transit systems attract a large number of non-CBD riders. During the morning peak period, more that 66 percent of San Diego Trolley passengers are bound to destinations other than the CBD, reflecting the emergence of many other activity centers in the region and the willingness of transit policy makers to serve those centers. A similar story applies in Portland, where the most heavily traveled bus route in the region connects with light rail in the suburbs and then runs along miles of strip malls before terminating at a regional mall, never coming near the CBD.

Multiple Destinations
The characteristics of the LRT-based, multi-destination transit networks in Portland and San Diego appear to us to cater to the mobility needs of these rapidly growing, dispersed urban regions, which typify the future American metropolis. The success of these two systems demonstrates that transit can serve successfully the city of the future, not just the city of the past.

Other rapidly growing metropolitan areas that have incorporated light rail into their bus systems possess some of the characteristics of transit in Portland and San Diego and enjoy some of their success. We hope they incorporate more of the characteristics as time passes, and that other regions also adopt regional light rail and begin molding their bus systems around it. If these hopes come true, American transit will experience substantial and productive growth into the future.

Editor’s Note: The authors compiled data and reached these conclusions in a study funded by the Mineta Transportation Institute.

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