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 PDF

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.

Impact of the 65 Mph Speed Limit on Virginia's Rural Interstate Highways, 1989-1992

Impact of the 65 Mph Speed Limit on Virginia's Rural Interstate Highways, 1989-1992 PDF

Author: Jack D. Jernigan

Publisher:

Published: 1994

Total Pages: 48

ISBN-13:

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In April of 1987, Congress passed the Surface Transportation and Uniform Relocation Assistance Act (STURAA), which permitted states to raise their maximum speed limit on rural interstate highways to 65 mph. Virginia's 65 mph speed limit went into effect on July 1, 1988, for passenger vehicles and on July 1, 1989, for commercial buses. This is the final report in a series to examine the 65 mph speed limit in Virginia, and it summarizes Virginia's experience with the 65 mph speed limit from 1989 through 1992. Following the implementation of the 65 mph speed limit, average and 85th percentile speeds increased on Virginia's rural interstates, and fatal crashes and fatalities increased significantly. On Virginia's urban interstates, on which the speed limit remained at 55 mph, there was a smaller increase in average and 85th percentile speeds, but there was a slight, nonsignificant decrease in fatal crashes and fatalities. Absolute numbers of fatal crashes and fatalities were used in this analysis rather than rates because traffic volume increases on interstates are averaged for both rural and urban systems. Thus, if volumes increased more on rural interstates, comparisons of relative rates would be misleading. The data in this report clearly show that speeds, fatal crashes, and fatalities increased on Virginia's rural interstates after the implementation of the 65 mph speed limit. However, these increases appear to have plateaued in the last two years of the study. Reports from other states and from national studies reflect a general increase in travel speeds and fatal crashes on rural interstates, but there is conflicting evidence on whether the 65 mph speed limit is the cause. Likewise, there is conflicting evidence concerning whether differential speed limits for trucks and cars have had an impact on the frequency of crashes in states maintaining such differential limits.

The Impact of the 65 MPH Speed Limit on Virginia's Rural Interstate Highways Through 1990

The Impact of the 65 MPH Speed Limit on Virginia's Rural Interstate Highways Through 1990 PDF

Author: Cheryl Lynn

Publisher:

Published: 1992

Total Pages: 44

ISBN-13:

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In April of 1987, Congress passed the Surface Transportation and Uniform Relocation Assistance Act (STURAA), which permitted states to raise their maximum speed limit on rural interstate highways (rural interstates) to 65 mph. Virginia's 65 mph speed limit went into effect July 1, 1988, for passenger vehicles and on July 1, 1989, for commercial buses. This report is the fourth in a series of reports to examine the 65 mph speed limit in Virginia and summarizes 30 months of experience with the 65 mph speed limit. Following the implementation of the 65 mph speed limit, average and 85th percentile speeds increased on Virginia's rural interstates, and fatal crashes and fatalities increased significantly. On Virginia's urban interstates, on which the speed limit remained at 55 mph, there was a smaller increase in average and 85th percentile speeds, but there was not a significant increase in fatal crashes or fatalities. National data show a substantial increase in rural interstate fatalities in states that increased the rural interstate speed limit to 65 mph and a decrease in states that maintained a 55 mph speed limit. The data in this report clearly show that speeds, fatal crashes, and fatalities increased on Virginia's rural interstates after the implementation of the 65 mph speed limit. However, these data do not reflect causation. It is possible that factors other than the change in the speed limit such as changes in traffic volumes, trip patterns, or trip purposes-are responsible for part or all of the increase in fatal crashes and fatalities. Causative issues will be addressed in the final report in this series, to be published in 1993.

An Investigation of Issues Related to Raising the Rural Interstate Speed Limit in Virginia

An Investigation of Issues Related to Raising the Rural Interstate Speed Limit in Virginia PDF

Author: Jack D. Jernigan

Publisher:

Published: 1988

Total Pages: 158

ISBN-13:

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In April of 1987, Congress passed the Surface Transportation and Uniform Relocation Assistance Act of 1987, which allows the states to raise, without penalty, the speed limit on interstate highways outside of urbanized areas with a population of 50,000 or more. This study estimated that an increase in the rural interstate speed limit in Virginia would have both positive and negative outcomes.-The average speed traveled on the rural interstate highway system has already increased by 3.6 mph in Virginia; this is comparable to that experienced in states that have raised the speed limit. However, if the speed limit on the rural interstate highway system is raised from 55 mph to 65 mph, it is estimated that in the short run the average speed traveled on the rural interstate will increase by an additional 3 mph, from 60 mph to 63 mph. Increased speeds would be expected to result in increased stopping distances and an annual increase of between 6 and 18 fatalities and between 171 and 405 injuries. Further, injuries would likely be more severe as a result of the higher speeds traveled. If the average speed continues to increase in the long run, or if higher speeds spill over onto the urban interstate highway system or rural collector roads, then additional injuries and fatalities would be expected on those systems as well. On the other hand, the primary quantifiable benefit of the higher limit would be a savings of 1.3 million hours in business and commercial travel time. This study has also found that almost 60% of the Virginians surveyed would prefer a 65 mph speed limit to a 55 mph limit on the rural interstate highway system. Finally, because of the current speeds, the geometric design, and the accident history of the rural interstates in general, it would be possible to raise the speed limit without violating traffic engineering tenets for setting speed limits. However, if the speed limit is raised, establishing a truck speed limit differential below the limit established for passenger cars would promote increased speed variance between cars and trucks, thereby creating a more dangerous environment than if the speed limit were raised to the same level for both cars and trucks.

The Impact of the 65 Mph Speed Limit on Virginia's Rural Interstate Highways Through 1989

The Impact of the 65 Mph Speed Limit on Virginia's Rural Interstate Highways Through 1989 PDF

Author: Jack D. Jernigan

Publisher:

Published: 1990

Total Pages: 59

ISBN-13:

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In April 1987, Congress passed the Surface Transportation and Uniform Relocation Assistance Act (STURAA) which permitted states to raise their maximum speed limit on rural interstate highways (rural interstates) to 65 mph. Since then, 40 states, including Virginia have adopted a 65 mph maximum speed limit. Virginia's 65 mph speed limit became effective for passenger cars on July 1, 1988, and for commercial buses on July 1, 1989. The findings presented in this report summarize 18 months of experience with the 65 mph speed limit in Virginia.

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