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National Highway Traffic Safety Administration (NHTSA) Notes
National Highway Traffic Safety Administration (NHTSA) Notes
Effect of Increased Speed Limits in the Post-NMSL Era National Highway Traffic Safety Administration Commentary: Does Speed Really Kill? B Tilman Jolly, MD Department of Emergency Medicine George Washington University Medical Center Washington DC Section Editors Joan S Harris National Highway Traffic Safety Administration B Tilman Jolly, MD Department of Emergency Medicine George Washington University Washington DC Jeffrey W Runge, MD Department of Emergency Medicine Carolinas Medical Center Charlotte, NC Knox H Todd, MD, MPH Rollins School of Public Health Emory University Atlanta, GA
2 6 6
Effect of Increased Speed Limits in the Post-NMSL Era [National Highway Traffic Safety Administration: Effect of increased speed limits in the post-NMSL era. Ann Emerg Med August 1998;32:266-267.] On November 28, 1995, the President signed into law the National Highway System Designation Act of 1995. The new law effectively eliminated the National Maximum Speed Limit (NMSL) after more than 2 decades of federal oversight. No longer required to comply with a single national speed limit to receive federal highway funding, 32 states raised their speed limits. The 1995 Act responded to traffic safety concerns of the NMSL elimination by requiring that the Secretary of Transportation report to Congress on the law’s implications. In response to this requirement, the National Highway Traffic Safety Administration (NHTSA), in cooperation with the Federal Highway Administration (FHWA), recently published their “Report to Congress: The Effect of Increased Speed Limits in the Post-NMSL Era.” Originally enacted in 1973 to conserve fuel during the Arab oil embargo, the 55-mph speed limit also helped to decrease traffic fatalities by 16% during its first year alone. Congress quickly voted to make the NMSL permanent in 1974. After its implementation, several government and private agencies conducted studies on the effect of the new law. A joint government task force concluded in 1980 that although “… determination of a precise, accurate estimate of lives saved by the NMSL … is problematic, there were 20,000 to 30,000 lives saved by the NMSL during the period of 1974–1978.”1
A Transportation Research Board study found that “the 55-mph speed limit save[d] 2,000 to 4,000 lives per year.”2 Conversely, a 1992 NHTSA report concluded that the optional increase to 65 mph on rural interstate highways caused a 30% rise in fatalities, or 500 additional lives lost, during 1990. The current report to Congress focuses on the associated costs of the NMSL elimination by grouping states into 3 categories based on their actions after the 1995 legislation: 11 states quickly raised their speed limits, an additional 21 followed suit over the next few months, and 19 states maintained the previous speed limit. New limits ranged from expanding 65-mph zones on rural interstates to new areas and increasing speed limits to 75 mph in several Western states. Analysis of the law’s effect was limited by the lack of data. Travel by roadway type, fuel consumption, medical costs, and other data were not consistently available from the states, and 1996 was the sole year of experience from which to conduct the analysis and prepare the report. This made it impossible to address the entire range of costs and benefits in the required analysis. However, several basic studies were conducted on the 3 groups of states using data from the NHTSA’s Fatality Analysis Reporting System. Total fatalities changed very little on a national level between 1995 and 1996 (1995: 41,817; 1996: 41,907), but fatalities—along with the number of fatal crashes, injured persons, and injury crashes—increased on interstates while decreasing on other roads. A preliminary assessment indicated that states with the higher speed limits experienced a 9% increase in interstate fatalities, or 350 more deaths, than historical trends predicted. Based
ANNALS OF EMERGENCY MEDICINE
32:2 AUGUST 1998
NHTSA NOTES
on NHTSA models, the total economic cost of 350 additional fatalities and associated injuries and crashes is more than $820 million in 1996 dollars. The patterns of change were strongest for the 11 states that raised their speed limits immediately after the enactment of the 1995 law. A linear regression model that accounted for a time trend and change in speed limits found a statistically significant increase in fatalities for these states versus predicted trends. The 21 states that increased limits later experienced a similar rise, but the rate of increase failed to reach significance. The states with no increase in speed limits saw a rise in fatalities that could be accounted for by historical trends alone. However, because of the previously mentioned data limitations, it is not known how increased travel on higher speed roads and other risk factors, such as alcohol involvement, may have contributed to the estimated increase in fatalities. In addition, 10 states (California, Idaho, Iowa, Michigan, Missouri, Montana, Nebraska, New Mexico, Texas, and Virginia) studied the effect of new speed limits in their own states. On a state-by-state basis, consistent patterns of increases or decreases in fatalities did not exist. However, among these 10 states only California and Montana increased speed limits soon after the NHS Act. Fatalities in California rose by 16% overall after speed limits increased. This represented the composite of an 8% decrease on freeways where the speed limit remained unchanged at 55 mph, coupled with increases of 22% and 12% on roads where speed limits increased to 65 mph and 70 mph, respectively. But because of the limited data, each state, including California, considered its findings preliminary or inconclusive. NHTSA and FHWA plan to continue studying the effect of increased speed limits at the national and state levels, particularly after additional years of experience and additional data are accrued at the higher limits. There will be continued focus on key areas of traffic safety such as increasing seat belt use, enforcing traffic laws, educating the public about safe driving, implementing roadway improvements, and ameliorating the effects of alcohol-involved driving. Such activities will help to offset possible increases in fatalities and injured persons that may be related to increased speed limits. The challenge for future analyses of the higher
AUGUST 1998
32:2
speed limits will be to take these traffic safety initiatives into account. Future studies will also need to address changes in vehicle miles traveled on the higher-speed roads. Finally, NHTSA, FHWA, and the Centers for Disease Control and Prevention have contracted with the Transportation Research Board to examine the criteria used by states to establish speed limits and to recommend improvements in the current methodology. Ensuring safe traffic practices will remain key in the post-NMSL era. 1. The Life-Saving Benefits of the 55 MPH NMSL: Report of the NHTSA/FHWA Task Force (DOT HS publication no 805-5590). Washington DC: US Department of Transportation, October 1980. 2. 55: A Decade of Experience (TRB special report 204). Washington DC: National Research Council, 1984.
Commentary: Does Speed Really Kill? [Jolly BT: NHTSA Notes commentary: Does speed really kill? Ann Emerg Med August 1998;32:267-268.] The simple answer to the title question is “Yes.” All other things being equal, the higher the speed of impact, the greater risk of injury. Of course, the answer is not that simple because the question is not that simple. Congress asked NHTSA and FHWA to answer a much more complex question. Do higher speed limits kill? The report summarized attempts to answer this question by examining the results of speed limit changes that were made by states after the NMSL was repealed. Speed, seat belt use, and drunk driving are the “big 3” among traffic safety issues. Previous NHTSA Notes commentaries have examined the sticky issues involved in setting policy on occupant restraints and impaired driving. The issues surrounding speed limits are no less sticky. At first, the safety benefits of the NMSL were merely a side effect, not the primary intention of the law. During the Arab oil embargo of 1973, speed limits were lowered to conserve fuel. When traffic fatalities decreased by 16% in 1 year, the safety benefits of lower speed limits became obvious. Although other factors may have also contributed to the fatality decrease at that time, the major contributor was determined to be the NMSL. The first change in the NMSL occurred in 1987. In that year, states were allowed to increase their maximum speed to 65 mph on rural
ANNALS OF EMERGENCY MEDICINE
interstate highways and a few other roads. Within a year, 39 states raised speed limits to the new level where allowed, placing 90% of rural interstates at the 65-mph limit. NHTSA estimated that the fatality toll on these roads was 30% higher than might be expected, translating into 500 deaths in 1 year. Despite these and similar findings, the NMSL was abandoned completely in 1995. This report to Congress focuses on the effects of that repeal. How and why did this law change in the first place? By 1995, the original reason for the 55-mph speed limit was gone. Gasoline prices were at their lowest constant dollar level in decades. All one needs to do now is look in any nearby parking lot to see drivers’ lack of concern about energy conservation on our roadways. Once the energy issue weakened, safety was left alone against “motorists’ rights” and “states’ rights.” The issue of states’ rights has become a familiar one in many settings over the last 2 centuries. In the traffic safety area, opponents of speed limits, motorcycle helmet laws, and tougher drunk driving standards have all used the argument of state autonomy to support their position. The only state mandates that now remain regarding traffic safety are the national minimum drinking age of 21 years and zero tolerance for underage drunk driving. Both of these mandates operate by penalizing the states with reductions in highway funding for failure to comply. Recently, there was a similar measure before Congress to make .08 blood alcohol content the national drunk driving standard. States’ rights advocates opposed this proposal, arguing that these issues should be decided at the state level. Instead of adopting a single national standard, Congress enacted a multiyear program of incentive grants to states to encourage them to enact and enforce their own .08 per se laws. The motorists’ rights groups are frequently driven by specific lobbying interests. One of the most active is the National Motorists Association (NMA). According to their Web site (www.motorists.com), this organization has been “advocating, representing, and protecting the interests of North American motorists since 1982.” This group claims credit for repeal of the NMSL. The NMA vigorously opposes reductions in speed limits. The group also publishes articles opposing numerous highway safety initiatives, such as .08 blood alcohol
2 6 7
NHTSA NOTES
legislation, camera-based enforcement, primary seat belt laws, radar detector restrictions, traffic calming, graduated licensing, daytime running lights, and other accepted traffic safety measures. Although it is unclear how many people actually support the NMA, it is fairly clear that the group is well organized and can be influential. Much like ABATE (American Brotherhood Aimed Toward Education), which focuses on motorcycle helmet laws, the NMA uses a very organized member base to get its points across to state and national legislators. Using a combination of technologies, these groups communicate their concern about issues to decisionmakers on a regular basis. The World Wide Web now gives them a forum for providing members and interested parties with documents, talking points, fact sheets, and sample legislation. No doubt readers have heard that a law that reduced public safety was passed in their respective state legislatures. Maybe a motorcycle helmet law was repealed, or .08 drunk driving standard was defeated. Maybe speed
limits increased or were removed altogether. In some cases, large, well-financed groups have been effective in influencing legislators. However, in many cases, special interest groups use sophisticated networking techniques to promote their views. A good letter-writing, fax, or E-mail campaign can create the impression of large-scale constituent support for specific legislation, such as repeal of the NMSL. The report to Congress examines the results of the national policy change. And for emergency physicians the report’s conclusions are no surprise. Increases in speed limits are associated with increases in traffic deaths. As with most studies, subgroup analysis was difficult for a number of reasons. Individual state statistics present a less compelling picture than do national numbers. At the very least, further study is warranted. For that reason, NHTSA is now in the process of awarding grants to several states, to enable them to study the effects of speed limit changes in their own state and to gather more complete data that will permit further analysis of these issues.
What role should emergency physicians play in all this? Compared with most activist groups, emergency physicians, those who possess the most dramatic and compelling experience with the aftereffects of motor vehicle crashes, have been strangely silent. Laws change, and we are left wondering how it happened. We should know that organized expression of scientific findings and personal experience can be highly effective and persuasive on these issues. Activist groups have been engaged in telling their own version very effectively for years. Remember—just like the members of these organizations, you too are a motorist, but more importantly you are also extremely well qualified to relate your own experiences and thereby to protect the health and safety of other motorists. As a citizen and physician, you can read these scientific reports, evaluate the data, and let your opinion be known. Your representative is waiting to hear from you. Reprint no. 47/1/91668 Reprints not available from the editors.
CALL FOR PAPERS Imaging of Trauma Patients Annals of Emergency Medicine is pleased to announce the solicitation of articles on the topic of imaging of trauma patients. Michael P Federle, MD, Chief of Abdominal Imaging of the University of Pittsburgh Medical Center, has agreed to serve as Guest Editor. The editors believe that this is a timely topic and will benefit practicing emergency physicians. All submissions will be peer reviewed by consultants selected for their expertise in this area. Papers accepted for publication will be published together in a special issue of the journal. Authors who would like their work considered for this special issue should submit manuscripts no later than January 15, 1999. Authors are requested to follow guidelines for submission as stated in the “Instructions for Authors” published monthly in the journal. Our editors look forward to your submission.
Submission deadline: January 31, 1999
2 6 8
ANNALS OF EMERGENCY MEDICINE
32:2
AUGUST 1998
Effect of Increased Speed Limits in the Post-NMSL Era National Highway Traffic Safety Administration Commentary: Does Speed Really Kill? B Tilman Jolly, MD Department of Emergency Medicine George Washington University Medical Center Washington DC Section Editors Joan S Harris National Highway Traffic Safety Administration B Tilman Jolly, MD Department of Emergency Medicine George Washington University Washington DC Jeffrey W Runge, MD Department of Emergency Medicine Carolinas Medical Center Charlotte, NC Knox H Todd, MD, MPH Rollins School of Public Health Emory University Atlanta, GA
2 6 6
Effect of Increased Speed Limits in the Post-NMSL Era [National Highway Traffic Safety Administration: Effect of increased speed limits in the post-NMSL era. Ann Emerg Med August 1998;32:266-267.] On November 28, 1995, the President signed into law the National Highway System Designation Act of 1995. The new law effectively eliminated the National Maximum Speed Limit (NMSL) after more than 2 decades of federal oversight. No longer required to comply with a single national speed limit to receive federal highway funding, 32 states raised their speed limits. The 1995 Act responded to traffic safety concerns of the NMSL elimination by requiring that the Secretary of Transportation report to Congress on the law’s implications. In response to this requirement, the National Highway Traffic Safety Administration (NHTSA), in cooperation with the Federal Highway Administration (FHWA), recently published their “Report to Congress: The Effect of Increased Speed Limits in the Post-NMSL Era.” Originally enacted in 1973 to conserve fuel during the Arab oil embargo, the 55-mph speed limit also helped to decrease traffic fatalities by 16% during its first year alone. Congress quickly voted to make the NMSL permanent in 1974. After its implementation, several government and private agencies conducted studies on the effect of the new law. A joint government task force concluded in 1980 that although “… determination of a precise, accurate estimate of lives saved by the NMSL … is problematic, there were 20,000 to 30,000 lives saved by the NMSL during the period of 1974–1978.”1
A Transportation Research Board study found that “the 55-mph speed limit save[d] 2,000 to 4,000 lives per year.”2 Conversely, a 1992 NHTSA report concluded that the optional increase to 65 mph on rural interstate highways caused a 30% rise in fatalities, or 500 additional lives lost, during 1990. The current report to Congress focuses on the associated costs of the NMSL elimination by grouping states into 3 categories based on their actions after the 1995 legislation: 11 states quickly raised their speed limits, an additional 21 followed suit over the next few months, and 19 states maintained the previous speed limit. New limits ranged from expanding 65-mph zones on rural interstates to new areas and increasing speed limits to 75 mph in several Western states. Analysis of the law’s effect was limited by the lack of data. Travel by roadway type, fuel consumption, medical costs, and other data were not consistently available from the states, and 1996 was the sole year of experience from which to conduct the analysis and prepare the report. This made it impossible to address the entire range of costs and benefits in the required analysis. However, several basic studies were conducted on the 3 groups of states using data from the NHTSA’s Fatality Analysis Reporting System. Total fatalities changed very little on a national level between 1995 and 1996 (1995: 41,817; 1996: 41,907), but fatalities—along with the number of fatal crashes, injured persons, and injury crashes—increased on interstates while decreasing on other roads. A preliminary assessment indicated that states with the higher speed limits experienced a 9% increase in interstate fatalities, or 350 more deaths, than historical trends predicted. Based
ANNALS OF EMERGENCY MEDICINE
32:2 AUGUST 1998
NHTSA NOTES
on NHTSA models, the total economic cost of 350 additional fatalities and associated injuries and crashes is more than $820 million in 1996 dollars. The patterns of change were strongest for the 11 states that raised their speed limits immediately after the enactment of the 1995 law. A linear regression model that accounted for a time trend and change in speed limits found a statistically significant increase in fatalities for these states versus predicted trends. The 21 states that increased limits later experienced a similar rise, but the rate of increase failed to reach significance. The states with no increase in speed limits saw a rise in fatalities that could be accounted for by historical trends alone. However, because of the previously mentioned data limitations, it is not known how increased travel on higher speed roads and other risk factors, such as alcohol involvement, may have contributed to the estimated increase in fatalities. In addition, 10 states (California, Idaho, Iowa, Michigan, Missouri, Montana, Nebraska, New Mexico, Texas, and Virginia) studied the effect of new speed limits in their own states. On a state-by-state basis, consistent patterns of increases or decreases in fatalities did not exist. However, among these 10 states only California and Montana increased speed limits soon after the NHS Act. Fatalities in California rose by 16% overall after speed limits increased. This represented the composite of an 8% decrease on freeways where the speed limit remained unchanged at 55 mph, coupled with increases of 22% and 12% on roads where speed limits increased to 65 mph and 70 mph, respectively. But because of the limited data, each state, including California, considered its findings preliminary or inconclusive. NHTSA and FHWA plan to continue studying the effect of increased speed limits at the national and state levels, particularly after additional years of experience and additional data are accrued at the higher limits. There will be continued focus on key areas of traffic safety such as increasing seat belt use, enforcing traffic laws, educating the public about safe driving, implementing roadway improvements, and ameliorating the effects of alcohol-involved driving. Such activities will help to offset possible increases in fatalities and injured persons that may be related to increased speed limits. The challenge for future analyses of the higher
AUGUST 1998
32:2
speed limits will be to take these traffic safety initiatives into account. Future studies will also need to address changes in vehicle miles traveled on the higher-speed roads. Finally, NHTSA, FHWA, and the Centers for Disease Control and Prevention have contracted with the Transportation Research Board to examine the criteria used by states to establish speed limits and to recommend improvements in the current methodology. Ensuring safe traffic practices will remain key in the post-NMSL era. 1. The Life-Saving Benefits of the 55 MPH NMSL: Report of the NHTSA/FHWA Task Force (DOT HS publication no 805-5590). Washington DC: US Department of Transportation, October 1980. 2. 55: A Decade of Experience (TRB special report 204). Washington DC: National Research Council, 1984.
Commentary: Does Speed Really Kill? [Jolly BT: NHTSA Notes commentary: Does speed really kill? Ann Emerg Med August 1998;32:267-268.] The simple answer to the title question is “Yes.” All other things being equal, the higher the speed of impact, the greater risk of injury. Of course, the answer is not that simple because the question is not that simple. Congress asked NHTSA and FHWA to answer a much more complex question. Do higher speed limits kill? The report summarized attempts to answer this question by examining the results of speed limit changes that were made by states after the NMSL was repealed. Speed, seat belt use, and drunk driving are the “big 3” among traffic safety issues. Previous NHTSA Notes commentaries have examined the sticky issues involved in setting policy on occupant restraints and impaired driving. The issues surrounding speed limits are no less sticky. At first, the safety benefits of the NMSL were merely a side effect, not the primary intention of the law. During the Arab oil embargo of 1973, speed limits were lowered to conserve fuel. When traffic fatalities decreased by 16% in 1 year, the safety benefits of lower speed limits became obvious. Although other factors may have also contributed to the fatality decrease at that time, the major contributor was determined to be the NMSL. The first change in the NMSL occurred in 1987. In that year, states were allowed to increase their maximum speed to 65 mph on rural
ANNALS OF EMERGENCY MEDICINE
interstate highways and a few other roads. Within a year, 39 states raised speed limits to the new level where allowed, placing 90% of rural interstates at the 65-mph limit. NHTSA estimated that the fatality toll on these roads was 30% higher than might be expected, translating into 500 deaths in 1 year. Despite these and similar findings, the NMSL was abandoned completely in 1995. This report to Congress focuses on the effects of that repeal. How and why did this law change in the first place? By 1995, the original reason for the 55-mph speed limit was gone. Gasoline prices were at their lowest constant dollar level in decades. All one needs to do now is look in any nearby parking lot to see drivers’ lack of concern about energy conservation on our roadways. Once the energy issue weakened, safety was left alone against “motorists’ rights” and “states’ rights.” The issue of states’ rights has become a familiar one in many settings over the last 2 centuries. In the traffic safety area, opponents of speed limits, motorcycle helmet laws, and tougher drunk driving standards have all used the argument of state autonomy to support their position. The only state mandates that now remain regarding traffic safety are the national minimum drinking age of 21 years and zero tolerance for underage drunk driving. Both of these mandates operate by penalizing the states with reductions in highway funding for failure to comply. Recently, there was a similar measure before Congress to make .08 blood alcohol content the national drunk driving standard. States’ rights advocates opposed this proposal, arguing that these issues should be decided at the state level. Instead of adopting a single national standard, Congress enacted a multiyear program of incentive grants to states to encourage them to enact and enforce their own .08 per se laws. The motorists’ rights groups are frequently driven by specific lobbying interests. One of the most active is the National Motorists Association (NMA). According to their Web site (www.motorists.com), this organization has been “advocating, representing, and protecting the interests of North American motorists since 1982.” This group claims credit for repeal of the NMSL. The NMA vigorously opposes reductions in speed limits. The group also publishes articles opposing numerous highway safety initiatives, such as .08 blood alcohol
2 6 7
NHTSA NOTES
legislation, camera-based enforcement, primary seat belt laws, radar detector restrictions, traffic calming, graduated licensing, daytime running lights, and other accepted traffic safety measures. Although it is unclear how many people actually support the NMA, it is fairly clear that the group is well organized and can be influential. Much like ABATE (American Brotherhood Aimed Toward Education), which focuses on motorcycle helmet laws, the NMA uses a very organized member base to get its points across to state and national legislators. Using a combination of technologies, these groups communicate their concern about issues to decisionmakers on a regular basis. The World Wide Web now gives them a forum for providing members and interested parties with documents, talking points, fact sheets, and sample legislation. No doubt readers have heard that a law that reduced public safety was passed in their respective state legislatures. Maybe a motorcycle helmet law was repealed, or .08 drunk driving standard was defeated. Maybe speed
limits increased or were removed altogether. In some cases, large, well-financed groups have been effective in influencing legislators. However, in many cases, special interest groups use sophisticated networking techniques to promote their views. A good letter-writing, fax, or E-mail campaign can create the impression of large-scale constituent support for specific legislation, such as repeal of the NMSL. The report to Congress examines the results of the national policy change. And for emergency physicians the report’s conclusions are no surprise. Increases in speed limits are associated with increases in traffic deaths. As with most studies, subgroup analysis was difficult for a number of reasons. Individual state statistics present a less compelling picture than do national numbers. At the very least, further study is warranted. For that reason, NHTSA is now in the process of awarding grants to several states, to enable them to study the effects of speed limit changes in their own state and to gather more complete data that will permit further analysis of these issues.
What role should emergency physicians play in all this? Compared with most activist groups, emergency physicians, those who possess the most dramatic and compelling experience with the aftereffects of motor vehicle crashes, have been strangely silent. Laws change, and we are left wondering how it happened. We should know that organized expression of scientific findings and personal experience can be highly effective and persuasive on these issues. Activist groups have been engaged in telling their own version very effectively for years. Remember—just like the members of these organizations, you too are a motorist, but more importantly you are also extremely well qualified to relate your own experiences and thereby to protect the health and safety of other motorists. As a citizen and physician, you can read these scientific reports, evaluate the data, and let your opinion be known. Your representative is waiting to hear from you. Reprint no. 47/1/91668 Reprints not available from the editors.
CALL FOR PAPERS Imaging of Trauma Patients Annals of Emergency Medicine is pleased to announce the solicitation of articles on the topic of imaging of trauma patients. Michael P Federle, MD, Chief of Abdominal Imaging of the University of Pittsburgh Medical Center, has agreed to serve as Guest Editor. The editors believe that this is a timely topic and will benefit practicing emergency physicians. All submissions will be peer reviewed by consultants selected for their expertise in this area. Papers accepted for publication will be published together in a special issue of the journal. Authors who would like their work considered for this special issue should submit manuscripts no later than January 15, 1999. Authors are requested to follow guidelines for submission as stated in the “Instructions for Authors” published monthly in the journal. Our editors look forward to your submission.
Submission deadline: January 31, 1999
2 6 8
ANNALS OF EMERGENCY MEDICINE
32:2
AUGUST 1998