automobiles
The Problem:
Motor vehicle accidents are one of the largest sources of public health harms. For people ages 1 to 34, motor vehicle crashes are the number one cause of death. Almost five million people each year suffer injuries during motor vehicle crashes that require emergency care. CDC Fact Sheet: Motor Vehicle Safety. Adverse weather conditions including snow and ice contribute to the incidence of motor vehicle crashes. Some evidence suggests that studded tires reduce accidents in inclement weather by providing better traction for motor vehicles. Studded tires are also known to damage road surfaces.
The Law:
States have the authority to ban or limit the use of studded tires. Some ban all studded tires, see Fl Rev Stats 316.299 (Florida), 9 ID Statutes 49-948 (Idaho), and Wisc. Trans Code 306.01 (Wisconsin). Other states have enacted seasonal limitations on their use, see 90 MGL 60 (Massachusetts), Ca Vehicle Code § 27454 (California), 67 Pa. Code. § 175.80 (Pennsylvania) and OH R.S.5589.081 (Ohio).
The Evidence:
According to the author of a peer-reviewed meta-analysis, laws banning studded tires result in small increases in motor vehicle crashes during winter months. Elvik. The effects on accidents of studded tires and laws banning their use: a meta-analysis of evaluation studies. Accident Analysis & Prevention 1999; 31:125-134. Of the 7 studies that Elvik identified as meeting the inclusion criteria, two were based in the United States, one in Canada, one in Germany and three in Japan. Six of the studies found that laws banning studded tires were associated with small increases in accidents during winter seasons. A meta-analysis revealed a weighted mean increase in winter accidents of 4 percent. This finding is consistent with meta-analysis results in the same review indicating that actual studded tire use reduces accident rates during winter.
The Bottom Line:
According to the author of a peer-reviewed meta-analysis, the evidence suggests that banning studded tires causes a small increase in motor vehicle accidents during the winter.
Publication Date: 12/07/2009
The Problem:
The leading cause of death for people age 34 and below in the United States is motor vehicle crashes. CDC: Motor Vehicle Safety Factsheet. Crashes occur due to impaired driving, inexperience, faulty vision and general recklessness. In congested areas, pedestrian safety is major public health concern. Approximately 700 children are killed each year by motor vehicles while walking. CDC: Reducing Childhood Pedestrian Injuries: Summary of a Multidisciplinary Conference.
The Law:
Traffic laws are designed to minimize motor vehicle crashes and to improve driver, passenger and pedestrian safety. Enforcing traffic laws can be difficult. Red light cameras take a picture of any car that fails to appropriately abide by a red light thereby endangering other drivers and pedestrians. The pictures are used to issue traffic citations, which often include sizable mandatory fines ($446 in Los Angeles: Photo Red Light Program). Twenty-four states and the District of Columbia have red light programs operating somewhere within their jurisdiction authorized either through state or local law. Governors’ Highway Association: Red Light Cameras. For an example of a state law authorizing the use of red light cameras, see RI Stat 42-28.9
The Evidence:
In a systematic review, Aeron-Thomas and Hess reviewed ten studies measuring the impact of red light cameras on motor vehicle crashes. Aeron-Thomas A, Hess, S. Red-Light Cameras for the Prevention of Road Traffic Crashes. The Cochrane Library. 2009, v.2. The reviewers found that the studies generally identified an association between the red light cameras and reductions in fatal crashes. However, weaker and often statistically insignificant relationships were observed between the cameras and overall crashes. On this basis, the reviewers concluded that there was sufficient evidence to establish the effectiveness of red light cameras as an intervention aimed at reducing fatal crashes, but that additional research is needed to validate the impact of these cameras on overall crashes and reckless driving generally.
The Bottom Line:
In the judgment of a Cochrane Collaborative expert panel, sufficient evidence exists to support red light cameras as an effective public health intervention to reduce motor vehicle crash fatalities, but there is insufficient evidence to validate the effectiveness of the cameras in reducing overall crashes.
Additional Information:
The Governors’ Highway Association provides online access to a table indicating in which states red light cameras are authorized or prohibited under state law.
Additional Resources: Governors’ Highway Association
Publication Date: 12/07/2009
The Problem:
The operation of motor vehicles while intoxicated is a major public health problem. Each year in the United States roughly 13,400 people die and an additional 255,500 are injured in motor vehicle crashes involving an alcohol-impaired driver. In 2006, these crashes accounted for almost a third of all U.S. traffic-related deaths. CDC: Impaired Driving Factsheet
The Law:
At selective breath testing (SBT) checkpoints, law enforcement officials may require a driver to submit to a breath test if the officer has a reasonable suspicion that the driver is intoxicated. As of September 2009, law enforcement agencies in 38 U.S. states and the District of Columbia may conduct sobriety checkpoints. Governors Highway Safety Association. Law enforcement agencies in 11 states are either not authorized by the state to conduct checkpoints or are prohibited from conducting checkpoints by interpretations of state constitutions or by statutes (e.g., Wisconsin, Wis. Stat. § 349.02(2)(a)). Law enforcement officers follow established procedures in conducting checkpoints, including using objective criteria to determine checkpoint locations and using a predetermined system for stopping cars (e.g., every fourth vehicle at a checkpoint is stopped). For examples of laws authorizing checkpoints, see Utah Code Ann. §§ 77-23-101 et seq (Utah) and Nev. Rev. Stat. § 484.359 (Nevada).
The Evidence:
In a systematic review, Shults et al. reviewed 13 studies on SBT checkpoints. Shults, et al. Reviews of Evidence Regarding Interventions to Reduce Alcohol-Impaired Driving. Am J Prev Med. 2001;21(4S):66-88. The reviewers found that the use of SBT checkpoints is effective in reducing fatal and nonfatal injuries involved in motor vehicle accidents and in the reduction of total alcohol related crashes. SBT checkpoints were found to reduce fatal and nonfatal injuries during crashes by a median 20 percent. An ancillary benefit noted in the underlying studies of SBT checkpoints is the increased policing of other illegal activity behavior such as driving with a suspended license.
The Bottom Line:
In the judgment of a Community Guide expert panel, there is strong evidence supporting the effectiveness of SBT sobriety checkpoints as a public health intervention aimed at reducing the harms associated with alcohol impaired driving.
Additional Information:
The Community Guide provides online access to a table summarizing the studies used in the review.
The Insurance Institute for Highway Safety provides online access to a table listing statutes and judicial interpretations authorizing or prohibiting sobriety checkpoints.
Publication Date: 12/07/2009
The Problem:
In the United States, motor vehicle–related accidents are the leading cause of death for all people under the age of 34. In 2000, motor vehicle crashes cost roughly $230 billion. CDC: Motor vehicle safety. The number of licensed drivers over the age of 65 has increased dramatically over the last decade. Drivers ages 80 and over have a higher rate of fatal crashes per miles driven than all other demographic groups except teenagers. The impact of aging on vision, cognitive functions, and other physical capacities has been identified as a contributing factor in motor vehicle crashes. CDC Website – Older Adult Drivers: Fact Sheet.
The Law:
State transportation and safety laws require different procedures and apply different standards in screening the vision of older drivers. For instance, to renew a license in California, an individual must have visual acuity of 20/40 with both eyes together and at least 20/40 in the stronger eye and 20/70 in the weaker eye, California Department of Motor Vehicles, CA Vehicle Code §12805; in Arizona, a minimum of 20/40 in one eye is required. Arizona Administrative Code: R17-4-502, R17-4-503. The age at which vision tests are required for renewal also varies (e.g., 40 years in Maryland (Maryland Transportation Code 16-115(h)) to 80 years in Virginia. Va. Code Ann. § 46.2-330 (C)). For another example of a state law requiring vision screening for individuals above a specified age, see FL Rev. State 322.18(5) (Florida).
The Evidence:
A Cochrane Collaboration Task Force attempted to conduct a systematic of studies assessing the impact of vision screenings for older drivers on motor vehicle crashes, but did not find any studies meeting its criteria. Subzwari S et al. Vision screening of older drivers for preventing road traffic injuries and fatalities. Cochrane Database of Systematic Reviews 2009, Issue 1. Art. No.:CD006252. The task force accordingly concluded that there is insufficient evidence to determine whether vision screening programs for individuals above a specified age are effective in reducing crashes among older adults.
The Bottom Line:
In the judgment of a Cochrane Collaborative expert panel, laws requiring vision screening are a plausible means of reducing crashes involving older drivers, but there is insufficient evidence to rigorously assess their effectiveness at this time.
Additional Information:
The Physician’s Guide to Assessing and Counseling Older Drivers, created by the American Medical Association (AMA) with support from the National Highway Traffic Safety Administration (NHTSA), is available online and provides substantial information about state policies regarding vision screening.
The International Council of Ophthalmology provides online access to a table of vision requirements for the fifty US states.
Additional Resources: Physician’s Guide to Assessing and Counseling Older Drivers, AMA, NHTSA, International Council of Ophthalmology
Publication Date: 12/07/2009
The Problem:
The operation of motor vehicles while intoxicated is a major public health problem. Each year in the United States roughly 13,400 people die and an additional 255,500 are injured in motor vehicle crashes involving an alcohol-impaired driver. These crashes account for 32 percent of all U.S. traffic-related deaths and cost roughly $51 billion a year. CDC: Impaired Driving Factsheet.
The Law:
Blood alcohol per se laws set a blood alcohol limit at which an individual is considered legally impaired (i.e., impairment is “per se” because actual inability to function need not be established). Currently, all states set their BAC limit at 0.08 percent; some previously set the BAC levels at 0.10 percent. For examples of BAC per se laws, see Cal. Veh. Code §23152 (California), Fla. Stat. §316.193 (Florida), K.S.A. §8-1567 (Kansas), M.R.S. §2411 (Maine), N.M. Stat. Ann. §66-8-102 (New Hampshire), N.M. Stat. Ann. §66-8-102 (New Mexico), N.C. Gen. Stat. §20-138.1 (North Carolina), O.R.S. 813.010 (Oregon), Utah Code §41-6a-502 (Utah), 23 V.S.A. §1201 (Vermont), and Va. Code Ann. §18.2-266 (Virginia).
The Evidence:
In a Community Guide systematic review, Shults et al. reviewed eight studies that examined the impact of lowering the BAC limit to 0.08 percent on the rate of alcohol-related motor-vehicle deaths. Shults, et al. Reviews of Evidence Regarding Interventions to Reduce Alcohol-Impaired Driving. Am J Prev Med. 2001;21(4S):66-88.According to the reviewers, the underlying studies reveal a considerable association between the adoption of 0.08 percent BAC laws and a decline in alcohol-related motor-vehicle deaths; the median reduction in motor vehicle fatalities after the laws were adopted was 7 percent. Shults et al view these studies as strong evidence of the effectiveness of 0.08 BAC laws as a public health intervention. However, they caution that most of the BAC laws analyzed were enacted along with, or were supplemented by, other preventive drunk-driving laws, such as Administrative License Revocation (ALR) laws, making it difficult to isolate the exact magnitude of the impact of BAC laws.
The Bottom Line:
In the judgment of a Community Guide expert panel, there is strong evidence that laws adopting decreased BAC levels effectively reduce alcohol-related motor-vehicle deaths.
Additional Information:
The Community Guide provides online access to a table summarizing the results of each study it reviewed.
Additional Resources: The Community Guide
Publication Date: 12/07/2009
The Problem:
The operation of motor vehicles while intoxicated is a major public health problem. Each year in the United States roughly 13,400 people die and an additional 255,500 are injured in motor vehicle crashes involving an alcohol-impaired driver. In 2006, these crashes accounted for almost a third of all U.S. traffic-related deaths. CDC: Impaired Driving Factsheet.
The Law:
In an effort to reduce drunk-driving recidivism, municipalities and states have experimented with ignition interlock programs. Ignition interlock devices disable a car’s ignition until the driver provides a breath sample that confirms that the driver’s blood alcohol content (BAC) is under the requisite limit. Participation in ignition interlock programs is sometimes required as a condition of sentences for violating drunk- driving laws. Initially, participation in the US was generally on a voluntary basis (e.g., violators could participate to regain their driving privileges earlier than otherwise provided) or was left to the court’s discretion and implemented only for repeat offenders. For examples of ignition interlock laws, see 75 Pa.C.S. §§ 88.1-88.8 (Pennsylvania), 90 MGL 24(c)(2) (Massachusetts), and A.R.S. §28-1381(I)(6) (Arizona).
The Evidence:
In a systematic review, Willis et al. reviewed 14 studies in the U.S. and Canada evaluating the effects of ignition interlock programs on drunk-driving recidivism. Willis et al. Alcohol ignition interlock programmes for reducing drink driving recidivism. Cochrane Database of Systematic Reviews. 2004; Issue 3. The underlying studies measured three types of outcomes: (1) recidivism rates while the driver participated in the ignition interlock program, (2) recidivism rates after the ignition interlock device was removed from the vehicle, and (3) recidivism rates during the entire study period. The reviewers found that interlock program participants were less likely to repeat offend than the control group. The impact was even more pronounced for repeat offenders. However, in each instance, recidivism returned to pre-intervention rates after the devices were removed. Though effective as a short term intervention, continued research on the effects of ignition interlock programs on drunk-driving recidivism over longer time periods is needed.
The Bottom Line:
In the judgment of a Cochrane Collaboration expert panel, ignition interlock programs reduce drunk-driving recidivism, but only while the devices are attached.
Additional Information:
Mothers Against Drunk Driving (MADD) maintains an online table listing the states with ignition interlock laws.
Additional Resources: Mothers Against Drunk Driving
Publication Date: 12/07/2009
The Problem:
The operation of motor vehicles while intoxicated is a major public health problem. Each year in the United States roughly 13,400 people die and an additional 255,500 are injured in motor vehicle crashes involving an alcohol-impaired driver. In 2006, these crashes accounted for almost a third of all U.S. traffic-related deaths. CDC: Impaired Driving Factsheet.
The Law:
Blood alcohol per se laws set a blood alcohol limit at which an individual is considered legally impaired (i.e., impairment is “per se” because actual inability to function need not be established). Currently, all states set their BAC limit at 0.08 percent; some previously set the BAC levels at 0.10 percent. For examples of BAC per se laws, see Cal. Veh. Code §23152 (California), Fla. Stat. §316.193 (Florida), K.S.A. §8-1567 (Kansas), M.R.S. §2411 (Maine), N.M. Stat. Ann. §66-8-102 (New Hampshire), N.M. Stat. Ann. §66-8-102 (New Mexico), N.C. Gen. Stat. §20-138.1 (North Carolina), O.R.S. 813.010 (Oregon), Utah Code §41-6a-502 (Utah), 23 V.S.A. §1201 (Vermont), and Va. Code Ann. §18.2-266 (Virginia).
The Evidence:
In a Community Guide systematic review, Shults et al. reviewed nine studies that examined the impact of lowering the BAC limit to 0.08 percent on the rate of alcohol-related motor-vehicle deaths. Shults, et al. Reviews of Evidence Regarding Interventions to Reduce Alcohol-Impaired Driving. Am J Prev Med. 2001;21(4S):66-88. According to the reviewers, the underlying studies reveal a considerable association between the adoption of 0.08 percent BAC laws and a decline in alcohol-related motor-vehicle deaths; the median reduction in motor vehicle fatalities after the laws were adopted was 7 percent. Shults et al view these studies as strong evidence of the effectiveness of 0.08 BAC laws as a public health intervention. However, they caution that most of the BAC laws analyzed were enacted along with, or were supplemented by, other preventive drunk-driving laws, such as Administrative License Revocation (ALR) laws, making it difficult to isolate the exact magnitude of the impact of BAC laws.
The Bottom Line:
In the judgment of a Community Guide expert panel, there is strong evidence that laws adopting decreased BAC levels effectively reduce alcohol-related motor-vehicle deaths.
Publication Date: 12/07/2009
The Problem:
The operation of motor vehicles while intoxicated is a major public health problem. Each year in the United States roughly 13,400 people die and an additional 255,500 are injured in motor vehicle crashes involving an alcohol-impaired driver. In 2006, these crashes accounted for almost a third of all U.S. traffic-related deaths. Drivers age 16 to 20 who engage in drunk driving pose an especially dangerous risk to themselves and other motorists. CDC: Impaired Driving Factsheet.
The Law:
All U.S. states currently set the minimum legal drinking age at 21 years (MLDA21). Federal legislation withholds federal highway funds from states that do not adopt an MLDA of 21 years (23 U.S.C. § 158). For examples of MLDA21 laws, see TX Alcoholic Beverage Code § 106.04 (Texas), Conn. Gen. Stat. 30-1(12) and Conn. Gen. Stat. §30-89 (Connecticut).
The Evidence:
Two independent systematic reviews of the relevant studies of this intervention have found a robust association between raising the MLDA to 21 and reductions in alcohol-related crashes. In a Community Guide systematic review, Shults et al. reviewed 33 studies that examined the effect of MLDA21 on fatal and nonfatal crashes likely to have involved alcohol. Shults, et al. Reviews of Evidence Regarding Interventions to Reduce Alcohol-Impaired Driving. Am J Prev Med. 2001;21(4S):66-88. Seventeen of the underlying studies evaluated the impact of raising the MLDA to 21, 11 evaluated laws that lowered the MLDA, and remaining 18 used regression analysis to measure changes in both directions. The review found a median reduction in alcohol-related crashes of 17 percent associated with raising the MLDA and a median increase of 8 percent in alcohol-related crashes associated with lowering the MLDA.
Wagenaar and Toomey reviewed 48 studies that measured the impact of MLDA21 on alcohol consumption and reviewed 57 studies that measured the impact of MLDA21 on alcohol-related crashes. Wagenaar, Toomey. Effects of Minimum Drinking age Laws: Review and Analyses of the Literature from 1960 to 2000. Journal of Studies on Alcohol. 2002(14 Suppl):206-25. Across the 48 studies, the authors identified 27 measures finding a statistically significant inverse relationship between MLDA21 and alcohol consumption (8 found a statistically insignificant inverse relationship; 5 found a positive relationship). Some of the measures included, for example, self-reported alcohol consumption and sale of particular alcoholic beverages. Fifty-two measures were indentified finding a statistically significant inverse relation between MLDA21 and crashes (12 found a statistically insignificant inverse relationship; 2 found a positive relationship). These measures included a broad range of types of injuries and crashes outcomes (e.g., nighttime fatal crashes, alcohol-related crashes).
The Bottom Line:
In the judgment of a Community Guide expert panel and the authors of a peer-reviewed systematic study, there is strong evidence to support the effectiveness of MLDA21 as an intervention aimed at reducing alcohol involved motor vehicle crashes.
Additional Information:
The Community Guide provides online access to a table summarizing the results of each study it reviewed.
Additional Resources: The Community Guide
Publication Date: 12/07/2009
The Problem:
In 2008, 968 children under the age of 15 died from injuries suffered during motor vehicle crashes and approximately 168,000 other children were injured. CDC: Child Passenger Safety Factsheet. The use of child safety seats has been found to substantially reduce the risk of mortality to infants in motor-vehicle accidents (70 percent) and in children ages 1 to 4 years (47 precent to 54 percent). Yet, each year children are injured and killed due to the nonuse or improper use of child safety seats. Zaza S, et al. Recommendations to reduce injuries to motor vehicle occupants increasing child safety seat use, increasing safety belt use, and reducing alcohol-impaired driving. Am J Prev Med. 2001;21(4S):16–22. It is estimated that universal proper child safety seat use could save roughly 160 lives and prevent 20,000 injuries each year. Zaza S, et al. Reviews of evidence regarding interventions to increase use of child safety seats. Am J Prev Med. 2001;21(4S):31-47
The Law:
Today, every state has a law requiring children to be restrained in federally-approved child safety seats while riding in motor-vehicles. These laws differ from state to state based on number of factors (e.g., age, height and weight of the children requiring safety seats). All current child safety seat laws allow for primary enforcement, meaning a police officer can stop a driver solely for a violation of such laws. Child restraint/belt use laws: The Insurance Institute for Highway Safety, Highway Loss Data Institute. For examples of child safety seat laws, see La. R.S. 32:295 (Louisiana), Tenn. Code Ann. § 55-9-602 (Tennessee), Ala. Code § 32-5-222 (Alabama) and N.J.S. 39:3-76.2a (New Jersey).
The Evidence:
In a systematic review, Zaza et al. reviewed nine studies that evaluated the effectiveness of child safety seat laws in reducing rates of childhood motor-vehicle injuries. Zaza S, et al. Reviews of evidence regarding interventions to increase use of child safety seats. Am J Prev Med. 2001;21(4S):31-47. The underlying studies focused on laws that were passed in every state in the United States between the years 1978 and 1986. The reviewers found a 35 percent median reduction in fatal childhood injuries and 17.3 percent reduction in overall motor-vehicle child injuries following the introduction and enforcement of child safety seat laws. The effects of additional requirements in particular states (for example, requiring a particular seating position or providing for harsher penalties) could not be determined from the available studies. The reviewers also identified a 13 percent increase in the use of child safety seat use subsequent to the adoption of child safety seat laws.
The Bottom Line:
There is strong evidence to support the effectiveness of child safety seat laws in substantially reducing injuries to children during motor vehicle crashes, according to a Community Guide expert panel.
Additional Resources: Insurance Institute for Highway Safety
Publication Date: 12/07/2009
The Problem:
Safety belts saved approximately 164,753 lives between 1975 and 2002 according to the National Highway Traffic Safety Administration (NHTSA). However, despite rising rates of safety belt use in the United States over the past 20 years, many American still do not consistently wear safety belts. David J. Houston and Lilliard E. Richardson, Jr., “Getting Americans to buckle up: The efficacy of state seat belt laws,” Accident Analysis and Prevention, 37 (2005) 1114–1120, at 1114
The Law:
Primary enforcement seatbelt laws authorize police officers to stop drivers solely because individuals in a vehicle are not complying with safety belt laws. Secondary enforcement, in contrast, only authorizes enforcement of safety belt laws in conjunction with another offense (i.e., drivers cannot be stopped if the only offense is not wearing a belt). For example of primary enforcement safety belt laws, see GA Code Ann § 40-8-6 (Georgia) and Fla Stat § 316.614 (Florida).
The Evidence:
In a systematic review, Dinh-Zarr et al. reviewed 13 studies that examined the effectiveness of primary enforcement safety belt laws as a means of reducing injuries related to motor vehicle crashes. Dinh-Zarr TB, et al. Reviews of evidence regarding interventions to increase the use of safety belts. Am J Prev Med. 2001;21(4S): 48-65. Nine of the reviewed studies compared the effectiveness of primary enforcement laws to that of secondary enforcement laws in the US; the other four measured the impact of changing from a secondary enforcement law to a primary enforcement law. Three studies focused their assessment on the impact of enacting primary enforcement legislation on specific populations (drunk drivers, African-American and Hispanics). The review found that primary enforcement laws are more effective in reducing fatal injuries and in increasing the frequency of safety belt use than secondary enforcement laws. Primary laws were found to reduce fatal injuries by a median 8 percent and to increase observed safety belt use a median 14 percent. Two studies found that primary enforcement laws increased safety-belt use by African-Americans and Hispanics compared to whites. There was no evidence in these studies that the difference was based on differential enforcement.
The Bottom Line:
Safety belt laws work, but there is strong evidence to support that primary enforcement safety belt laws are more effective than secondary enforcement laws in increasing seat belt use and reducing crash injuries.
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Public Health Law Research is a national program of the Robert Wood Johnson Foundation. It is housed at the Temple University Beasley School of Law.