The term can refer to many combinations of key traits, such as designating certain lanes on streets for exclusive bus use, setting traffic signals to give preferential treatment to buses, creating separate boarding areas where passengers prepay and providing special platforms to facilitate boarding of handicapped passengers.
To make bus rapid transit a true commuting alternative to privately owned vehicles, the buses should be able to run on separate rights-of- way, allowing the buses to move much faster during rush hours. The rights-of-way do not have to be fully segregated from all other vehicles. Bus rapid transit vehicles can also share High Occupancy Vehicle lanes with cars containing two or more passengers, including vanpools. If the total bus and HOV traffic levels on such lanes are low enough to permit rapid movement, the combined lanes might lure many lone drivers into sharing rides. However, to be politically acceptable on highways, such HOV lanes must be additions to, not conversions of, existing lanes--making the creation of them costly.
Houston has long used this combined bus lane-HOV approach. According to its report to the American Public Transit Association, the Houston METRO system has 182 miles of separated HOV rights-of-way within six major freeways radiating from downtown. The average rush-hour speed on normal freeway lanes is 24 miles per hour, but speeds on the HOV lanes are more than twice as fast. In 2000, Houston's 1,100 buses provided 86.7 million unlinked trips, an average of just under 300,000 per weekday. METRO claims that its six HOV lanes carry as many passengers during rush hours as would 24 normal lanes.
How has this system affected overall commuting in the Houston region? In 2000, 14.3 percent of all commuters in the region used carpools-- that's above the national average, which is 12.2 percent. The percentage of Houston commuters using public transit was 3.6--that's slightly above the national rate, which is 3.5 percent outside New York City. Thus, the major effect of Houston's HOV lane system plus bus rapid transit has been to increase carpooling, rather than the use of public transit.
How about traffic congestion? The Texas Transportation Institute scored the Houston region's Travel Time Index--the ratio of how long it takes to go a fixed distance during rush hours divided by the time it takes in uncongested periods--at 1.38 in 2000. That was below the average for the 10 very large regions analyzed. Moreover, Houston's Travel Time Index increased only 5.3 percent from 1990 to 2000, compared with 7.0 percent for all 10 very large regions.
It is interesting to compare Houston's approach with that adopted by Portland, Oregon. Portland eschewed building many more road lanes, even HOV lanes, in favor of creating a light-rail system, which it more than doubled in size during the 1990s to 64.9 miles. Although the Portland region's 2000 population was only 46 percent of Houston's, Portland's bus and light rail systems combined produced 86.2 million unlinked trips--almost exactly the same as Houston's METRO. The Portland region's percentage of public transit commuters--7.1 percent- -was nearly double Houston's 3.6, but Portland had fewer carpoolers-- 11.5 percent versus Houston's 14.4 percent. Thus, both regions had very similar combined totals for both transit and carpooling--18.6 percent in Portland versus 17.9 percent in Houston.
However, Portland's traffic congestion as measured by the Texas Transportation Institute was slightly worse than Houston's, even though very large regions typically have more intensive congestion than large ones. Moreover, from 1990 to 2000, Portland's Travel Time Index rose 21.6 percent to 1.40 while Houston's increased only 5.3 percent to 1.38. The share of each day that Portland's drivers spent in congestion soared 52 percent from 1990 to 2000; whereas Houston's share rose only 18 percent. This occurred even though both regions gained about 26 percent in population during that decade.
A study by the U.S. General Accounting Office concluded that bus rapid transit systems were much less expensive to build than light- rail systems, but both had about the same operating costs. If bus rapid transit systems are combined with HOV lanes as in Houston, they have a dual impact, diverting traffic from normal lanes in ways that light rail cannot. Bus rapid transit also has greater flexibility. Its vehicles can leave designated lanes and travel on normal streets. While light rail seems more in vogue right now, limited federal funds for such systems are increasing interest in bus rapid transit alternatives.
