Status of the Nation's Highways, Bridges, and Transit:
2002 Conditions and Performance Report
|Chapter 4: Operational Performance|
Part I: Description of Current System
Part II: Investment Performance Analyses
Part III: Bridges
Part IV: Special Topics
Part V: Supplemental Analyses of System Components
The operational performance of transit affects its attractiveness as a means of transportation. People will be more inclined to use transit that is frequent and reliable, travels more rapidly, has adequate seating capacity, and is not too crowded. When vehicles become too crowded, the quality of a transit trip decreases and may provide an incentive to riders to shift to a different transportation mode.
Frequency and Reliability of Services
The frequency of transit services varies considerably according to location and time of day. Transit service is more frequent in urban areas and during rush hours, in locations and during times when the demand for transit is highest. Studies have found that transit passengers consider the time spent waiting for a transit vehicle to be less well spent than the time spent traveling in a transit vehicle. The higher the degree of uncertainty in waiting times, the less attractive transit becomes as a means of transportation, and the fewer users it will attract.
Exhibit 4-15 shows information on waiting times, from the 1995 Nationwide Personal Transportation Survey by FHWA. This is the most recent nationwide survey providing this information. It does not reflect changes in service levels that may have occurred since TEA-21. Waiting times vary according to the characteristics of the passenger making the trip. Passengers with limited incomes and without access to a private vehicle are the most dependent on transit, and are most likely using transit for basic mobility and have fewer alternatives to get to their destination. These riders have, on average, the highest tolerance for delay and unreliability, and experience an average waiting time of 12.1 minutes and variation (standard deviation) in waiting time of 13.6 minutes. Passengers with incomes above the poverty line who have access to a personal vehicle, but who choose to travel by transit, experience the lowest average waiting time of 7.3 minutes and a variation in waiting times of 9.3 minutes. People in this group often use transit to avoid traffic congestion. Riders who have abovepoverty incomes but who do not have a car, wait slightly longer for transit service (8.9 minutes), but have a slightly lower degree of variation in the length of time that they wait (8.8 minutes). These riders are often those that benefit from location efficiency, i.e., they live in an area where it is not necessary to have a car because transit is readily available.
Transit travel conditions are often crowded. In 1995, 27.3 percent of the people sampled by the Nationwide Personal Transportation Survey were unable to find a seat upon boarding a transit vehicle (Exhibit 4-16). Seats were not available upon boarding for 29.7 percent of trips by passengers with below average incomes and without cars, compared to about 25 percent for trips made by passengers with access to cars and above poverty incomes. The percentage of all passengers unable to find seats during rush hours was even higher, 31.3 percent. Approximately 32 percent of transit trips started during peak hours.
Average Operating Speeds
Average vehicle operating speeds as experienced by passengers are based on the number of miles that transit vehicles travel and the number of hours spent transporting passengers. Based on data from the National Transit Database, the average operating speed for each type of transit vehicle is calculated by dividing vehicle revenue miles by vehicle revenue hours for each type of transit mode. These average modal operating speeds are weighted by the number of passenger miles traveled annually on each type of transit mode to derive passenger-mile weighted average speeds for rail, non-rail, and total transit, as shown below in Exhibit 4-17. This measurement is intended to be passenger oriented, i.e., provide an indicator of the average speed that a passenger will travel on each transit mode rather than the pure operational speed characteristics of a transit mode.
The average transit vehicle operating speed declined in 2000 to 19.6 miles per hour, just under the 14-year average of 19.9 miles. The passenger-mile weighted average operating rail speed has declined unevenly since 1991, falling to 24.9 miles per hour in 2000. Rails speeds were highest between 1991 and 1997, ranging between 26.0 to 27.6 miles per hour, up from 24.9 miles per hour in 1990. The passenger-mile weighted average operating speed of non-rail vehicles—which is affected by traffic, road, and safety conditions—has remained relatively constant over the last 14 years, averaging 13.6 miles per hour. Between 1987 and 2000, the passenger-mile weighted average operating speed of rail vehicles has been about 12 miles per hour faster than of non-rail transit vehicles.
As Exhibit 4-18 shows, the average operating speed of rail vehicles differs considerably from one type to another. Commuter rail provides the fastest service with an average passengerweighted operating speed of 30.1 miles per hour in 2000. Heavy rail and light rail travel more slowly with average speeds, in 2000, of 21.1 and 17.8 miles per hour. In the same year, the average operating speed for transit vehicles traveling on automated guideways was 10.9 miles per hour; on monorails it was 7.6 miles per hour, on cable cars 4.0 miles per hour, and on inclined planes, i.e., transit vehicles traveling on track a short distance up a steep hill, 3.4 miles per hour.
As shown in Exhibit 4-19, the passenger-mile weighted speeds of non-rail transit vehicles also cover a wide range. Vanpools, which tend to travel long distances on highways, have a faster average operating speed than other non-rail transit vehicles, 36.9 miles per hour in 2000. Buses and ferry boats traveled an average of 10.5 miles per hour. Demand response and publico vehicles were slightly faster at 15.8 and 13.6 miles per hour, respectively. Trolleys were the slowest modes of non-rail transit, traveling at average speeds of 7.4 miles per hour. The only jitney service in the United States providing speed data to FTA operated in San Francisco until 2000. It had an average speed of 7 miles per hour in 1999.
Vehicle utilization is measured as the ratio of the total number of vehicles operated in maximum scheduled service, adjusted by a capacity factor, to the total number of passenger miles traveled annually in each mode. Vehicle utilization is shown in Exhibit 4-20 and graphed in Exhibit 4-21. Commuter rail has consistently had the highest utilization rate. In 2000, commuter rail utilization reached a new high of 914.3 thousand passenger miles per vehicle, up substantially from 855.2 in 1999, and an average of 828 for the 1990s as a whole. Heavy and light rail per vehicle utilization rates also reached new highs in 2000 of 783.7 and 687.6 thousand passengers, respectively. These levels were well above the average utilization rates experienced in the 1990s. Heavy rail utilization rates also increased in recent years, after a dip in the early 1990s. Light rail has exhibited the largest increase in vehicle utilization, consistently increasing since 1991. Utilization of buses, on the other hand, dropped slightly to 393.2 thousand passenger miles in 2000; the utilization of demand response, including van pools, varied over the 1990s with no discernable trend and was 168.8 thousand passengers in 2000.