Primary Seat Belt Laws Research Articles

Mandatory seatbelt laws and traffic fatalities: A reassessment

AbstractUsing data from the Fatality Analysis Reporting System for the period 1983–1997, Cohen and Einav (Review of Economics and Statistics 2003; 85[4]: 828–843) found that mandatory seatbelt laws were associated with a 4–6% reduction in traffic fatalities among motor vehicle occupants. After successfully replicating their two‐way fixed effects estimates, we (1) add 22 years of data (1998–2019) to capture additional seatbelt policy variation and observe a longer post‐treatment period, (2) employ the interaction‐weighted estimator proposed by Sun and Abraham (2021) to address potential bias due to heterogeneous and dynamic treatment effects, and (3) estimate event‐study models to investigate pre‐treatment trends and explore lagged post‐treatment effects. Consistent with Cohen and Einav (2003), our updated estimates show that primary seatbelt laws are associated with a 5 to 9% reduction in fatalities among motor vehicle occupants. Estimated effects of secondary seatbelt laws are smaller in magnitude and sensitive to model choice.

Is There Racial Bias in the Enforcement of Primary Seat Belt Laws? Evidence from Veil of Darkness Tests

Abstract State mandatory seat belt laws have become stricter over time, allowing for a vehicle to be stopped solely for a suspected seat belt infraction. While effective in reducing traffic fatalities, this additional discretion may also come with the possibility of increased racial targeting. Using individual-level traffic stop data, I combine recent advances in the Veil-of-Darkness test with a difference-in-difference identification strategy to estimate whether primary seat belt laws are associated with changes in the racial composition of seat belt stops. Results indicate that under primary seat belt enforcement, a black individual is 1.138–1.222 times more likely than a white individual to be stopped for a seat belt violation under the good visibility of daylight compared to the poor visibility of darkness. These additional stops end mostly in warnings, suggesting the law is used to increase the number of pretextual stops made, specifically on black drivers.

Motor Vehicle Crash and Hospital Charges in Front- and Rear-Seated Restrained and Unrestrained Adult Motor Vehicle Occupants.

There are reports that historically higher mortality observed for front- compared to rear-seated adult motor vehicle (MV) occupants has narrowed. Vast improvements have been made in strengthening laws and restraint use in front-, but not rear-seated occupants suggesting there may be value in expanding the science on rear-seat safety. Methods. A linked 2016–2017 hospital and MV crash data set, the Crash Outcomes Data Evaluation System (CODES), was used to compare characteristics of front-seated (n = 115,939) and rear-seated (n = 5729) adults aged 18 years and older involved in a MV crash in New York State (NYS). A primary enforced seat belt law existed for front-seated, but not rear-seated occupants. Statistical analysis employed SAS 9.4. Results. Compared to front-seated occupants, those rear-seated were more likely to be unrestrained (21.2% vs. 4.3%, p < 0.0001) and to have more moderate-to-severe injury/death (11.9% vs. 11.3%, p < 0.0001). Compared to restrained rear-seated occupants, unrestrained rear-seated occupants had higher moderate-to-severe injury/death (21.5% vs. 7.5%, p < 0.0001) and 4-fold higher hospitalization. More than 95% of ejections were unrestrained and had 7-fold higher medical charges. Unrestrained occupants’ hospital stays were longer, charges and societal financial costs higher. Conclusions. These findings extend the science of rear-seat safety in seriously injured rear-seated occupants, document increased medical charges and support the need to educate consumers and policy makers on the health and financial risks of adults riding unrestrained in the rear seat. The lack of restraint use in adult rear-seated motor vehicle occupants consumes scarce health care dollars for treatment of this serious, but largely preventable injury.

Are out-of-state drivers more seatbelt compliant than in-state drivers in the United States?

Introduction: This study explored the seatbelt use among in-state and out-of-state drivers in relation to their personal (age, gender, license status, etc.) and crash characteristics (time, location, roadway factors, etc.) using crash data over a 10-year period (2010–2019) from the Fatality Analysis Reporting System (FARS). Method: Comparison of seatbelt use between the two groups (in-state vs. out-of-state drivers) were conducted using Z-test statistics. Logistic regression models were developed to examine the probability of seatbelt use among each group. Results: New findings in this study showed that out-of-state drivers were 5% more likely than in-state drivers to use seatbelts. Regardless of the driver’s age, gender, license status, vehicle type, and injury severity, seatbelt use was significantly higher among out-of-state drivers. Moreover, irrespective of the location (rural or urban), the season (time, day, or month), road type (arterial, local streets, etc.), and jurisdictional seatbelt law (primary or secondary), out-of-state drivers were more seatbelt compliant than in-state drivers. Finally, out-of-state drivers traveling from states with secondary/no seatbelt laws exhibited higher seatbelt compliance rate in primary seatbelt law states than in states with less strict laws (i.e., secondary/no law). Practical Applications: The findings in this study are critical to addressing a myriad of policy questions related to seatbelt laws and seatbelt use. Future research should focus on the disparity in seatbelt use between the two groups and determine intervention strategies that are effective at promoting seatbelt use across the United States. Additionally, given the significant differences in driver seatbelt use behavior based on the type of seatbelt law, if states with less strict laws upgrade to primary seatbelt laws, there likely will be increases in seatbelt compliance in those states.

Long-term safety evaluation of the primary seat-belt law

Many states in the United States have passed the primary enforcement seat-belt law. Though there is strong evidence from previous studies that enhanced seat-belt enforcement interventions can substantially increase seat-belt use, thereby reducing fatalities. It is still necessary to evaluate the long-term effects of implementing the primary seat-belt law. In this study, changes in fatalities over time after the primary seat-belt law enactment are investigated using before-and-after study with the comparison group methods for fatality modification factors (FMFs). This study confirms that the number of adult fatalities without seat-belt has significantly decreased by 17.29%. Another key finding is that the fatality rates in states with a higher maximum fine amount are significantly lower than those with a lower one, however, the decrease in fatality trend is not as effective above about $100 fine. Implementing the primary seat-belt law is significantly effective in reducing fatalities without seat-belt in the long-term. Meanwhile, the relationship between fatalities reduction and the maximum fine amount is not positively linear related. It is imperative that states with the secondary seat-belt laws must reform their seat-belt laws to the primary seat-belt law. An appropriate fine amount can be determined to maximize the effectiveness of the primary seat-belt law.

Obesity and motor vehicle deaths: a panel-data analysis

PurposeThis paper analyzes the impact of obesity on the probability of a motor vehicle fatality (highway death rate) and on its component probabilities: the probability of a fatality, given a crash (vulnerability rate) and the probability of a crash (crash rate).Design/methodology/approachUsing state-level data for 1995–2015, the paper estimates models explaining all three rates. Explanatory factors include obesity and a representative set of potential determinants.FindingsResults indicate that obesity has a statistically significant positive relationship with the highway death rate and the crash rate. Also having a statistically significant positive association with at least one of the three rates are the proportions of young and old drivers, alcohol consumption, the ratio of rural to urban vehicle miles and temperature. Factors with a statistically significant negative relationship with at least one of the rates include primary seat belt laws and precipitation. In 2016, a total of 928 traffic fatalities could have been avoided if obesity rates decreased by one percentage point.Practical implicationsSeat belts and crash dummies should be better designed to fit and represent those with higher BMIs, and education efforts to increase seat belt use should be supplemented with information about the adverse impact of obesity on highway safety.Originality/valueThis paper uses 21 years of state-level information, including socio-economic and regulation data, and contributes to the existing research on the relationship between obesity and highway safety.

Seatbelt laws and seatbelt use among front- and rear-seat vehicle occupants in fatal crashes in the United States

Seatbelt laws are deemed effective at increasing seatbelt use, consequently, reducing fatalities associated with motor vehicle crashes in the United States. Previous studies have provided significant insights about the effectiveness of seatbelt laws, however, studies exploring passenger seatbelt use accounting for the variations in seatbelt laws are not well documented in the literature. Seatbelt laws vary by whether they cover front-seat occupants only or include rear-seat passengers as well. The primary objective of this study was to investigate the differences in adult seatbelt compliance rate based on six categories of seatbelt laws in the United States using crash data. In this present study, six categories of seatbelt laws are considered ranging from no seatbelt law to primary seatbelt law covering all vehicle occupants. Using Tukey-type multiple comparison test, a positive relationship between seatbelt laws and adult seatbelt use was found. Specifically, states with stricter seatbelt laws, that is primary law for all front- and rear-seat occupants, exhibit higher seatbelt compliance rate than those with less strict (partial primary/secondary laws) or no seatbelt laws. Given the significant differences in adult seatbelt use based on our study design (using six categories of seatbelt laws), the analysis support that if states upgrade their seatbelt laws from no/secondary laws to primary laws covering all vehicle occupants, there likely will be positive impacts on adult seatbelt use. The findings in this study are to inform and support decision policies and intervention strategies that are effective at promoting safety for motor vehicle occupants.

Factors Associated With Unrestrained Young Passengers in Motor Vehicle Crashes.

We analyzed 2011-2015 Fatality Analysis Reporting System and National Automotive Sampling System data and included vehicles with a young passenger (≤19 years old) in a crash. Driver and passenger characteristics were compared by using bivariate analyses separately for fatal and nonfatal crashes. Logistic regression analyses were performed on a combined data set to predict passenger restraint use. In unadjusted bivariate models, unrestrained drivers had a higher probability of having an unrestrained passenger across all passenger age groups for both fatal and nonfatal crashes. In multivariate logistic regression models that included both fatal and nonfatal crashes and were adjusted for several driver and passenger characteristics, unrestrained drivers had a higher risk of having an unrestrained young passenger across all age groups. In both fatal and nonfatal crashes, a driver being unrestrained is a strong predictor of the child passenger also being unrestrained. Policy and regulation to better ensure that drivers are properly restrained (eg, expanding primary seat-belt laws to all states) may serve as effective means for increasing rates of proper child-occupant-restraint use.

Alcohol and marijuana use among young injured drivers in Arizona, 2008–2014

Objective: We examined alcohol and marijuana use among injured drivers aged 16–20 years evaluated at Arizona level 1 trauma centers during 2008–2014.Methods: Using data from the Arizona State Trauma Registry, we conducted a descriptive analysis of blood alcohol concentration (BAC) and qualitative test results (positive or negative) for delta-9-tetrahydrocannabinol (THC) by year of age, sex, race, ethnicity, injury severity, seat belt use, motorcycle helmet use, and type of vehicle driven. To explore compliance with Arizona’s motorcycle helmet law requiring helmet use for riders <18 years old, we examined helmet use by age.Results: Data on 5,069 injured young drivers were analyzed; the annual number of injured drivers declined by 41% during the 7-year study period. Among the 76% (n = 3,849) of drivers with BAC results, 19% tested positive, indicating that at least 15% of all drivers had positive BACs. Eighty-two percent of the BAC-positive drivers had BACs ≥0.08 g/dL, the illegal threshold for drivers aged ≥21 years. Among the 49% (n = 2,476) of drivers with THC results, 30% tested positive, indicating that at least 14% of all drivers were THC-positive. American Indians and blacks had the highest proportion of THC-tested drivers with positive THC results (38%). In addition, 28% of tested American Indians had positive results for both substances, more than twice the proportion seen in all other race or ethnic groups. Crude prevalence ratios suggested that drivers who tested positive for alcohol or THC were less likely than those who tested negative to wear a helmet or seat belt, further increasing their injury risk. Helmet use among motorcyclists was lower among 16- and 17-year-old riders compared to 18- to 20-year-olds, despite Arizona’s motorcycle helmet law requiring riders aged <18 years to wear a helmet.Conclusions: About 1 in 4 injured drivers aged 16–20 years tested positive for alcohol, THC, or both substances. Most drivers with positive BACs were legally intoxicated (BAC ≥0.08 g/dL). All substance-using young drivers in this study were candidates for substance abuse screening and possible referral to treatment. Broader enforcement of existing laws targeting underage access to alcohol and alcohol-impaired driving could further reduce injuries among young Arizona drivers. To further reduce crash-related injuries and fatalities among all road users, the state could consider implementing a primary enforcement seat belt law and a universal motorcycle helmet law.

2440 - Analyzing Border to Border (B2B): Nationwide Campaign to Increase Seat Belt Use and Enforcement along State Borders

Each year, approximately 40,000 Americans die in traffic crashes and almost three million are injured. In 2016, with a 90 percent national seat belt use rate, seat belts prevented 14,668 fatalities. In 2010, the medical and work loss combined cost for occupant fatalities in motor vehicle crashes was over $12 billion. Sadly, many of these fatalities, injuries, and costs could have been prevented if the victims had been wearing seat belts or were properly restrained in child seats. In 2015, only 52% of those killed in motor vehicle crashes were restrained. Despite an overall increase in seat belt use over the past decade, traffic crashes are still the leading cause of unintentional injury-related death in the United States. Primary seat belt laws have proven to be effective in increasing state’s seat belt use rate. When States upgrade their laws from secondary to primary, significant increases in safety belt use are often observed. This report will look at the National Highway Traffic Safety Administration’s Border to Border initiative aimed at addressing seat belt non-use. Border to Border (B2B) is a one-day seat belt-awareness effort coordinated by participating State highway safety offices and their respective law enforcement liaisons. The goal is to reduce seat belt fatalities in their regions by implementing the Click It or Ticket (CIOT) campaign brand. The B2B program aims to increase law enforcement participation by coordinating highly visible seat belt enforcement and providing seat belt fact sheets for drivers at heavily traveled and highly visible areas along state borders. The B2B initiative encourages cross-jurisdiction collaboration, across State borders, which will help law enforcement officers enforce seat belt laws. Since its inception in 2014, Region 2 has spearheaded the B2B program. Due to its size and success this year, NHTSA national headquarters is organizing the effort for 2018, which will include a 4-hour enforcement crackdown on May 21. This report will outline the expansion of the B2B program to a nationwide level. It will discuss state participation; engagement of law enforcement agencies, citations issued, and earned media. In addition to the results, it will look at the overall strengths and challenges of the initiative to inform future programs that require cross state collaboration by law makers, law enforcement, and public health programs globally.

Sociodemographic, Toxicological, and Lifestyle Characteristics of Seat Belt Users in a Nationally Representative Sample of US High School Students: Results from the 2015 Youth Risk Behavior Survey

Background Seat belts prevent death and serious injury in motor vehicle crashes (MVCs), but in 2015, 47% of drivers ages 15 to 19 who died in a crash were unrestrained. Attempts to increase teenage belt use have included high-visibility enforcement (e.g. primary seat belt laws and graduated driver licensing), but limited research exists regarding lifestyle behaviors associated with regular belt use among young drivers. The objective of this study is to explore the prevalence of healthy lifestyle behaviors associated with regular seat belt use among US high school students. Methods Data were used from the Centers for Disease Control and Prevention’s 2015 national Youth Risk Behavior Survey (YRBS), a nationally representative sample of US high school students. The YRBS assessed seat belt use as a passenger and other lifestyle behaviors during the 30 days before the survey, for 15,561 high school students. Seat belt use was coded into a dichotomous variable (regular/always v. irregular). Chi-square tests examined bivariate associations between regular seat belt use, demographic variables, and the prevalence of the following healthy lifestyle behaviors: hours of sleep, cigarette smoking, alcohol consumption, marijuana use, illegal prescription drug use, physical activity, and regular vegetable and water consumption. Results The prevalence of regular seat belt use during the 30 days before the survey was 61%. Regular belt use was more prevalent in males (χ2=3.97; degrees of freedom=1; p=.046), positively associated with age (χ2=43.82; df=6; p Conclusions High school students who reported regularly wearing their seat belts were mostly male, older, White, and had no alcohol or drug use. This study also suggests that a diverse range of healthy lifestyle behaviors are associated with a higher proportion of regular seat belt use. Encouraging healthy lifestyle behaviors in students, particularly those who drive, may positively influence traffic safety behaviors, including regular seat belt use.

Assessment of Three Affiliated Tribes Primary Seat Belt Intervention

Tribal populations experience a greater risk for traffic injuries than other populations. The Three Affiliated Tribes on the Fort Berthold Reservation recently enacted a primary seat belt law to improve public safety on its roads. A comparison of field observation study results from early in the intervention and from a later observation study revealed that gains in seat belt use may have eroded in towns. On highways, however, the intervention appears to have produced sustained gains in seat belt use by male drivers of cars and sport utility vehicles. Previous studies showed that the longer-term success of the primary law intervention requires ongoing reinforcement with respect to education and enforcement activities.

Seat Belt Use Among Adult Workers - 21 States, 2013.

Roadway incidents involving motorized vehicles accounted for 24% of fatal occupational injuries in the United States during 2013 and were the leading cause of fatal injuries among workers.* In 2013, workers' compensation costs for serious, nonfatal injuries among work-related roadway incidents involving motorized land vehicles were estimated at $2.96 billion.(†) Seat belt use is a proven method to reduce injuries to motor vehicle occupants (1). Use of lap/shoulder seat belts reduces the risk for fatal injuries to front seat occupants of cars by 45% and the risk to light truck occupants by 60%.(§) To characterize seat belt use among adult workers by occupational group, CDC analyzed data from the 2013 Behavioral Risk Factor Surveillance System (BRFSS) and found that not always using a seat belt was significantly associated with occupational group after controlling for factors known to influence seat belt use. Occupational groups with the highest prevalences of not always using a seat belt included construction and extraction; farming, fishing, and forestry; and installation, maintenance, and repair. To increase seat belt use among persons currently employed, states can enact and enforce primary seat belt laws, employers can set and enforce safety policies requiring seat belt use by all vehicle occupants, and seat belt safety advocates can target interventions to workers in occupational groups with lower reported seat belt use.

Motor vehicle crash fatalities in states with primary versus secondary seat belt laws: A time-series analysis: Lee LK, Monuteaux MC, Burghardt LC, et al. Ann Intern Med. 2015;163:184-190

Motor vehicle crash fatalities in states with primary versus secondary seat belt laws: A time-series analysis: Lee LK, Monuteaux MC, Burghardt LC, et al. Ann Intern Med. 2015;163:184-190

Motor Vehicle Crash Fatalities in States With Primary Versus Secondary Seat Belt Laws: A Time-Series Analysis.

Motor vehicle crashes (MVCs) remain a leading cause of injury-related deaths in the United States. Primary seat belt laws allow vehicle occupants to be ticketed solely for not wearing seat belts, and secondary laws allow ticketing only for failure to wear seat belts in the setting of other violations. To determine the association between MVC fatality rates and primary versus secondary seat belt laws. Retrospective time-series analysis. United States, 2001 to 2010. MVC fatalities in occupants aged 10 years or older identified in the Fatality Analysis Reporting System. Population-based rates of fatal crashes. There were 283 183 MVC fatalities in occupants aged 10 years or older from 2001 to 2010 (overall rate, 13.0 per 100 000 persons). In 2001, the mean fatality rate was 14.6 per 100 000 persons, 16 states had primary seat belt laws, and 33 states had secondary laws. In 2010, the mean fatality rate was 9.7 per 100 000 persons, 30 states had primary seat belt laws, and 19 states had secondary laws. In the multivariate regression model, states with primary seat belt laws had lower MVC fatality rates than states with secondary laws (adjusted incidence rate ratio, 0.83 [95% CI, 0.78 to 0.90]). Only fatalities were analyzed from the database, and the degree of law enforcement could not be ascertained. States with primary seat belt laws had lower rates of MVC fatalities than those with secondary laws. Adoption of primary seat belt laws may offer optimal occupant protection. None.

Determinants of seat belt use: A regression analysis with FARS data corrected for self-selection

We develop a methodology to use FARS data as an alternative to NOPUS in estimating seat belt usage. The advantages of using FARS over NOPUS are that (i) FARS is broader because it contains more variables relevant for policy analysis, (ii) FARS allows for easy multivariate regression analysis, and finally, (iii) FARS data is more cost-effective. We apply a binary logit model in our analysis to determine the likelihood of seat belt usage given various occupant, vehicle, and built environment characteristics. Using FARS data, we derive coefficient estimates for categories such as vehicle occupants' age and night time seat belt use that observational surveys like NOPUS cannot easily provide. Our results indicate that policies should focus on passengers (as opposed to drivers), male and young vehicle occupants, and that law enforcement should focus on pick-up trucks, rural roads, and nights. We find evidence that primary seat belt laws are effective. Although this is primarily a methodological paper, we present and discuss our results in the context of public policy so that our findings are relevant for road safety practitioners, researchers, and policymakers.

Analyzing seat belt usage from accident data

Intensive traffic enforcement has been shown to promote the compliance of roadway motorists and reduce traffic violations. However, prior research on seat belt enforcement has generally neglected the analysis of belt usage in non-fatal accidents, usage by backseat passengers, and usage during nighttime hours. In addition, few studies have examined the effectiveness of blitz campaigns and, to date, none has included usage statistics involving accident victims—individuals at an increased risk of belt non-use. This study sought to include these factors in evaluating whether Ohio’s annual Click It or Ticket seat belt enforcement campaign positively impacted belt use in a 60 day, pretest/post-test experiment over five separate years: 2005, 2006, 2007, 2008, and 2009. Data were collected from all 88 Ohio counties based upon official police reports of seat belt usage by occupants in motor vehicle accidents regardless of crash severity, occupant seating, or time of day. The results indicate that belt usage increased significantly after the 2005 and 2008 campaigns, but no impact was found among the remaining years. In addition, the data suggest that belt usage may have been maintained at optimal levels according to previous research. These findings are discussed along with the possible policy implications of transitioning Ohio to a primary seat belt law State to increase compliance.

SEATBELT USE AMONG DRUNK DRIVERS IN DIFFERENT LEGISLATIVE SETTINGS

We present evidence from the Fatality Analysis Reporting System and Behavioral Risk Factor Surveillance System that shows increased seatbelt use following the concurrent presence of stricter blood alcohol content thresholds and primarily enforced seatbelt laws. This suggests that inebriated drivers may use their seat belts more judiciously to avoid being identified as a drunk driver by law enforcement. The interactive effect of stricter drunk driving laws and primary seatbelt laws are also shown to be more effective than either law passed in isolation in terms of reducing traffic fatalities. (JEL K4, I18)

Seatbelt usage: is there an association with obesity?

Wearing a seatbelt can prevent motor vehicle crash deaths. While primary seatbelt laws are designed to encourage vehicle passengers to wear seatbelts by allowing law enforcement officers to issue tickets when passengers do not wear seatbelts, discomfort may discourage obese individuals from wearing a seatbelt. The objective of this study is to assess the association between state-level obesity and seatbelt usage rates in the US, and to examine the possible role played by seatbelt laws in these associations. The strength of the association between obesity rates, seatbelt usage, and primary seatbelt laws at the state level is investigated using data from 2006 to 2011. Linear regression analysis is employed. This model estimates that increasing the obesity rate by 1% in a state where a primary seatbelt law (by which law enforcement officers can issue a ticket when seatbelts are not worn) is in effect is associated with a 0.06% decrease in seatbelt usage. However the same percentage of increase in the obesity rate in a state where no primary seatbelt law is in effect is associated with a 0.55% decrease in seatbelt usage. The magnitude of the statistical association between state obesity rates and state-level seatbelt usage is related to the existence of a primary seatbelt law, such that obesity has less impact on seatbelt usage in states where primary seatbelt laws are in effect.

Modeling the Impact of Rescinding Michigan's Primary and Secondary Seat Belt Laws on Death and Injury from Passenger Vehicle Crashes

Background: Seat belts are the most effective method of decreasing fatal and nonfatal motor vehicle crash injury. Advocacy groups have recently been successful in enacting repeals of mandatory motorcycle helmet laws in several states. In some states, this has prompted renewed efforts aimed at repealing mandatory seat belt laws.Purpose: To evaluate and quantify the potential impact of rescinding seat belt laws on annual crash-related fatalities, nonfatal injuries, and associated economic costs, using Michigan as a model, to inform the national debate.Methods: Proportional injury rates were calculated utilizing police-reported statewide passenger vehicle crash data from 1999 and 2002, where belt use rates approximate estimates associated with repeal of primary and secondary seat belt laws. Proportional rates were applied to the most recent year of crash data (2011) to estimate changes in statewide fatalities and nonfatal injuries. National cost estimates were applied to injury data to calculate associated economic costs.Results: Full repeal of the seat belt law is estimated to result in an additional 163 fatalities, 13,722 nonfatal injuries, and an associated societal cost of $1.6 billion annually. Repeal of the primary seat belt law only is estimated to result in an additional 95 fatalities, 9156 nonfatal injuries, and an associated societal cost of $1.0 billion annually.Conclusions: This analysis suggests that repealing the either the primary or full seat belt law would have a substantial and negative impact on public health, increasing motor vehicle crash related fatality, nonfatal injury, and associated economic costs.