Paul L. Zador

Fatal Crash Involvement and Laws against Alcohol-Impaired Driving

It is estimated that in 1985 about 1,560 fewer drivers were involved in fatal crashes because of three types of drinking-driving laws. The laws studied were per se laws that define driving under the influence using blood alcohol concentration (BAC) thresholds; laws that provide for administrative license suspension or revocation prior to conviction for driving under the influence (often referred to as “administrative per se” laws); and laws that mandate jail or community service for first convictions of driving under the influence. It is estimated that if all 48 of the contiguous states adopted laws similar to those studied here, and if these new laws had effects comparable to those reported here, another 2,600 fatal driver involvements could be prevented each year. During hours when typically at least half of all fatally injured drivers have a BAC over 0.10 percent, administrative suspension/revocation is estimated to reduce the involvement of drivers in fatal crashes by about 9 percent; during the same hours, first offense mandatory jail/community service laws are estimated to have reduced driver involvement by about 6 percent. The effect of per se laws was estimated to be a 6 percent reduction during hours when fatal crashes typically are less likely to involve alcohol. These results are based on analyses of drivers involved in fatal crashes in the 48 contiguous states of the United States during the years 1978 to 1985.

HIGH SCHOOL DRIVER EDUCATION: FURTHER EVALUATION OF THE DEKALB COUNTY STUDY

The DeKalb County, Georgia, study is the largest experimental evaluation of high school driver education to date. Detailed reanalyses of data from that study reveal that students assigned to an enhanced driver education program (Safe Performance Curriculum) were more likely to obtain drivers licenses, to be in car crashes and to have traffic violations than control students not assigned to driver education. Students assigned to a minimal program of high school driver education (Pre-Driver Licensing Curriculum) were also more likely than control students to obtain licenses, but the difference was smaller than for the enhanced program and they were not significantly more likely to be in crashes or to have violations. Students in the more limited course were less likely than those in the enhanced course to complete the course in a timely manner, which suggests that exposure differences may explain differences between the two groups. The results confirm that greater availability of driver education causes students to become licensed sooner, although the DeKalb study probably underestimates the effect. Because of this greater exposure, crashes and violations are incurred at an earlier age.

Injuries to children in automobiles in relation to seating location and restraint use

Abstract Findings in this study are based on 26,971 passengers less than 15 years of age in reported crashes in 1967 and later model year automobiles in North Carolina during calendar years 1973 and 1974. (1) Children least likely to be injured in crashes are restrained and in the back seat; those most likely to be injured are unrestrained and are in the front seat. Unrestrained children in the front right seat have the highest injury rate. (2) More than 90% of the children in the surveyed crashes were found unprotected by restraints—paralleling earlier findings for those in cars in general. (3) Back seat location reduced the injury rate by 28% among unrestrained children and 18% among restrained children. Use of restraints reduced the injury rate by 39% in the front seat and 31% in back. (4) Among unrestrained children, back seat location is advantageous for both males and females, for both younger and older children, and in automobiles of various sizes. The advantage of back seat location is most pronounced in frontal impacts. Laws in several European countries regarding belt use and seating location, by in effect forbidding restraint use by some children, may increase the likelihood that those children will be injured in crashes. It is recommended that in automobiles presently on the road without automatic restraints such as air cushions, children be restrained, preferably in the back seat, and that they never travel unrestrained in the front seat.

The Effect of Raising the Legal Minimum Drinking Age on Involvement in Fatal Crashes

The research method, statistical analysis and results are reported of a study of nine states which raised their legal minimum drinking ages between September 1, 1976 and January 1, 1980. Each of the nine states was paired with a comparison state in which the legal minimum drinking age remained unchanged during the study period. Data on driver involvement in fatal crashes from January 1975 through September 1980 were obtained from the Fatal Accident Reporting System. Only drivers of motor vehicles--automobiles, light trucks, vans, on-off road vehicles--were included. The results of this study indicate that when states raise the drinking age, there is a corresponding decrease in fatal crashes among law-affected drivers. There is also some evidence that raising the drinking age also effects younger drivers, but the reduction in the involvement of such drivers in fatal crashes was not statistically significant. As of January 1981 14 states have raised the legal drinking ages in recent years. It is estimated that these law changes result, each year, in about 380 fewer young drivers involved in nighttime fatal crashes. The societal benefits achieved in states that have raised their drinking ages are substantial.

The Legal Minimum Drinking Age and Fatal Motor Vehicle Crashes

The possible effect on highway losses of reducing the legal minimum drinking age was examined. Involvement of drivers under 21 in fatal crashes in Michigan, Wisconsin, and Ontario in which legal minimum drinking age was reduced from 21 to 18 in either 1971 or 1972 was compared with involvement of such drivers in Indiana, Illinois and Minnesota, states respectively contiguous to them in which the legal drinking age remained 21 during the period studied. Data from police reports were obtained on all recorded fatal crashes, whether or not the drivers were killed. There was a significant increase in involvement in fatal crashes of drivers under 21 in areas that changed the law, particularly in nighttime and single vehicle crashes where alcohol is most often involved. Fatal crash involvement of drivers under 21 in border states did not increase. The law change effected the perception and/or reporting of alcohol involvement by the police more than it affected the fatal crash rate.

The effect of city curfew ordinances on teenage motor vehicle fatalities.

Of 149 large cities surveyed, 72 were found to have nighttime curfew ordinances applying to teenagers of various ages. The typical city curfew identified starts at midnight, ends at 5 A.M., and affects all activity of teenagers ages 13-17 in a public place and unaccompanied by a parent. In comparisons of 47 cities with curfews covering 13- to 17-year-olds and 77 cities without curfews, curfews were associated with a 23% reduction in fatal injury for 13- to 17-year-olds for the 9 P.M.-5:59 A.M. time period. This is identical to the 23% reduction estimated for both fatal and nonfatal motor vehicle injuries for 13- to 17-year-olds in an earlier, more limited study of curfews in Detroit, Cleveland, and Columbus, Ohio.

Re-Analyses of the Effects of No-Fault Auto Insurance on Fatal Crashes

The effect of no-fault automobile insurance laws on fatal motor vehicles crashes was analyzed using data for states in the U.S. from 1976 to 1980. This investigation was prompted by an earlier claim that no-fault laws resulted in increased fatal crashes in the 16 states that adopted them. The present examination of the fatal crash data using multiple regression analysis provided no evidence in support of the claim that no-fault insurance laws restricting general liability have lead to increased fatal crashes in the United States.

ADOPTION OF RIGHT TURN ON RED: EFFECTS ON CRASHES AT SIGNALIZED INTERSECTIONS

Abstract By the end of the 1970s, all states in the U.S. had modified their laws to permit drivers to turn right on steady red at signalized intersections. Police-reported crash data from six states where permissive right turn on red (RTOR) laws were adopted during 1974–1977, as well as data from three states where the law in effect was unchanged throughout the period, were used to determine the effect of adopting such laws on the frequency of crashes involving right turning maneuvers at signalized intersections. The increase in the overall frequency of such crashes in states that adopted permissive right turn on red laws exceeded by more than 20% the comparable change in states that retained the same laws. Larger increases were found in urban areas (25%), and for pedestrian crashes (57%) especially in urban areas (79%). An increase of over 30% was found for child pedestrians, 100% for adults, and 110% for elderly pedestrians after adoption of RTOR.

City curfew ordinances and teenage motor vehicle injury

Several U.S. cities have curfew ordinances that limit the late night activities of minor teenagers in public places including highways. Detroit, Cleveland, and Columbus, which have curfew ordinances, were compared to Cincinnati, which does not have such an ordinance. The curfew ordinances were associated with a 23% reduction in motor vehicle related injury for 13- to 17-year-olds as passengers, drivers, pedestrians, or bicyclists during the curfew hours. It was concluded that city curfew ordinances, like the statewide driving curfews studied in other states, can reduce motor vehicle injury to teenagers during the particularly hazardous late night hours.

Mandatory Belt Use and Driver Risk Taking: An Empirical Evaluation of the Risk-Compensation Hypothesis

Despite empirical evidence of the lifesaving and injury-reducing benefits of federal motor vehicle safety standards, seat belt use laws, motorcycle helmet laws, and other government requirements for protecting people in crashes, the value of such policies has been challenged. The challengers hypothesize that the effectiveness of mandatory approaches are partially or wholly offset by changes in behavior by drivers who take greater risks, thus maintaining the same level of overall risk as before.