A Status Report to the Superintendent of Public Instruction on a Study of Optimal School Bus Speed Limits on Virginia Highways
A Status Report to the Superintendent of Public Instruction on a Study of Optimal School Bus Speed Limits on Virginia Highways

Author:

Publisher:

Published: 1988

Total Pages: 54

ISBN-13:

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The study was prompted by the fact that on Virginia's rural interstate highways there is a three-tiered speed limit: 45 mph for school buses, 55 mph for other buses and trucks, and 65 mph for passenger vehicles. On the urban interstate system, school buses are restricted to 45 mph, but other traffic has a 55 mph speed limit. Further, the speed limit for school buses on roads other than interstate highways is 35 mph or the minimum speed limit, whichever is greater, or 45 mph if the school bus neither loads nor discharges passengers between the points of origin and destination. The study will examine the safety characteristics of the current multi-tiered speed limits and how these characteristics relate to the operation of school buses. A survey of other states revealed that 17 states other than Virginia had statutes creating speed limits for school buses lower than those for other vehicles. Generally, these states restricted the speeds of school buses to 55 mph. Three other states have administrative regulations that restrict school buses to 55 mph. However, 19 states have no special laws or regulations governing school bus speed limits. Data acquisition is still in progress for the remaining states. Research is continuing on this project, and a final report on the subject is scheduled to be completed in September 1989.

Optimal Speed Limits for School Buses on Virginia Highways
Optimal Speed Limits for School Buses on Virginia Highways

Author: Jack D. Jernigan

Publisher:

Published: 1990

Total Pages: 136

ISBN-13:

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On Virginia's rural interstate highways there is a three-tiered speed limit: 45 mph for school buses, 55 mph for trucks, and 65 mph for other vehicles. On the urban interstate highways, school buses are restricted to 45 mph, but other traffic has a 55 mph speed limit. Speed theory suggests that (1) restricting school buses to slower speeds will not increase the potential severity of accidents that occur but that (2) slower speeds may function to increase the probability that a school bus will become involved in a crash with a faster-moving vehicle on the interstate highway system. The study found that 41 states allow school buses to travel at least 55 mph on the interstate highway system, and 22 states allow school buses to travel 65 mph on the rural interstate highways. Surveys of school administrators, school bus drivers, and policeagencies and other special interest groups indicated a majority opinion in favor of raising the speed limits for school buses from 45 mph to 55 mph on the rural interstate highway system but retaining the 45 mph maximum limit on the urban interstate highways and on other systems. A major reason cited for wanting an increase on the rural interstate highways was a fear that school buses are in danger of being struck from behind by faster-moving vehicles, especially heavy trucks. A detailed analysis of four years of Virginia accident data (including the one year of exposure to the 65 mph rural interstate speed limit for most traffic) indicated that only 17 crashes occurred during those years, resulting in only six injuries and no fatalities. These crashes were not attributable to the difference in speed limits or to collisions between heavy trucks and school buses. The accident data, therefore, did not support the reasons given by those surveyed for why a higher speed limit would be preferred. Further, because Virginia's school buses are equipped with a speed governor that limits the maximum speed of the bus, a higher speed limit would require raising the speed allowed by the governor. Therefore, this action might function to increase travel speeds not only on interstate highways but on other roads as well, which could have a deleterious effect on school bus safety on the primary and secondary systems. Thus, the study concluded that there are no compelling reasons for Virginia to raise the maximum speed· limits for school buses from 45 mph and that there are reasons that caution against raising the speed limit.

A Status Report on the Effects of the 65 Mph Speed Limit on Virginia's Rural Interstate Highway System
A Status Report on the Effects of the 65 Mph Speed Limit on Virginia's Rural Interstate Highway System

Author: Jack D. Jernigan

Publisher:

Published: 1989

Total Pages: 52

ISBN-13:

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In 1987, the Secretary of Transportation and Public Safety created a task force to study the potential effects of raising the speed limit on rural interstate highways in Virginia. In its 1988 session, the Virginia General Assembly passed legislation to increase the speed limit on rural interstate highways to 65 mph for passenger vehicles, but the 55 mph limit was retained for buses and large trucks. After implementation of the higher speed limit on July 1, 1988, the Secretary reconvened the task force to design a study to determine the effects of the changed speed limit. The Virginia Transportation Research Council was again asked to serve a the staff for the task force. The preliminary data provided in this report represent only 5 months of experience with the 65 mph speed limit and are presented for information only. Any conclusions drawn from these data would be inappropriate and perhaps incorrect. After the speed limit for cars was increased by 10 mph, the average and 85th percentile speeds traveled by all vehicles on the rural interstate system increased by 3 mph, to 63 mph and 68 mph, respectively. The average and 85th percentile speeds traveled by trucks and buses, for which the speed limit remained at 55 mph, decreased slightly. Between July 1 and November 30, 1988, there were 44 fatalities in 35 fatal crashes on rural interstate highways in Virginia. This was a 76 percent increase over the 25 fatalities and a 52 percent increase over the 23 fatal crashes for the same time period in 1987. In the states that increased the speed limit, there was a 41 percent increase overall in the number of fatalities, but in states that did not increase the speed limit, there was a 54 percent increase in fatalities--higher than that noted for states that increased the speed limit. Many of the crashes that accounted for the increase in the number of fatal crashes on rural interstate highways occurred on I-81, and all of the multiple-fatality crashes occurred on either I-81 or I-95. In comparison with 1987, the number of fatal crashes in 1988 included 5 more involving vehicles that ran off the road, 4 more involving tractor trailers, and 3 more involving pedestrians. In October 1988, there was an abnormally high number of fatal crashes and fatalities on Virginia's rural interstate highways, but no patterns were found to explain this 1-month abnormality. Because there are not sufficient data to determine the reasons for the increases in fatal crashes and fatalities, data will be gathered over a 5- year period to determine the effect of the changed speed limit on Virginia's rural interstate highways.