The influence of safety belt laws on self- reported safety belt use in the United States

We assessed rates and trends in safety belt use by presence and type of safety belt law using data from states participating in the 1984–1989 Behavioral Risk Factor Surveillance System. State(s) with a safety belt law allowing law enforcement officers to stop vehicles for occupants' failure to use safety belts (primary enforcement law) had greater and more rapid increases in safety belt use rates than did states with laws requiring that vehicles must first be stopped for some other violation before a citation or fine for occupants' failure to use safety belts could be imposed (secondary enforcement law). Larger and sustained increases in safety belt use occurred when safety belt laws became effective or when fines were imposed for violations than when laws were first enacted. These data suggest that primary enforcement laws result in greater and more rapid increases in safety belt use than do secondary enforcement laws, and that initial increases in safety belt use following implementation of laws are sustained.     

Traffic safety and the switch to a primary seat belt law: the California experience

This study explores whether the change of an existing seat belt law from secondary to primary enforcement enhances traffic safety. In particular, we examine traffic fatalities and injuries in California from 1988 to 1997. During the first half of this period, California law provided for secondary enforcement of its mandatory seat belt law, but in 1993 it upgraded the law to primary enforcement. Controlling for the number of motor vehicle collisions, a Box–Tiao intervention analysis of the time series is used to compare the monthly fatalities and injuries before and after the change in the enforcement provision. The results show that California experienced an improvement in traffic safety in terms of a significant reduction in injuries, but the change in enforcement provision had no statistically significant impact on fatalities.     

Seat belt use among African Americans,Hispanics, and Whites

OBJECTIVES: This study investigated seat belt use among White, Black, and Hispanic drivers, in cities in which standard enforcement of the belt use law is permitted (primary enforcement) and in cities in which a motorist has to be first cited for another offense (secondary enforcement). Socioeconomic and gender differences in belt use were also studied. METHODS: Belt use observations were obtained at gas stations in Boston, Chicago, Houston, and New York City. In short interviews with drivers, information on race/ethnicity and education was obtained. RESULTS: Belt use was higher in primary enforcement cities, among women, and among those with at least a college degree. In primary law cities there were no clear differences in belt use by race/ethnicity; in secondary cities African Americans were less likely than Whites or Hispanics to be belted, among populations both with and without college degrees. This is consistent with data from other studies indicating that African Americans are more sensitive than Whites to the enforcement of primary laws and are more likely to increase belt use when states shift from secondary to primary. There has been no evidence of enforcement bias against African Americans--increases in citations generally have been greater among Whites than African Americans once primary enforcement is implemented. CONCLUSIONS: More widespread application of primary laws--standard throughout the world but in only 17 US states and the District of Columbia--would increase belt use for all drivers, especially African Americans.     

The effects of standard enforcement on Michigan safety belt use

The purpose of this study was to assess the effects of standard enforcement legislation on safety belt use in Michigan through a series of seven statewide direct observation surveys. A secondary purpose of the study was to compare the results in Michigan to the results in other states that have changed the provision of their mandatory safety belt use law from secondary to standard enforcement. The study found that standard enforcement has been effective in increasing safety belt use in Michigan. Immediately following the implementation of standard enforcement, Michigan's belt use rate increased to 83.5%, 13.4 percentage points higher than the highest rate previously observed. One year after the change, safety belt use in Michigan was still nearly 10 percentage points greater than the highest observed rate before standard enforcement legislation was enacted. Results indicated that safety belt use decreased slightly in the year following the implementation of standard enforcement. This appears to be an overall trend across all observed groups, and not due to any single demographic category. The results also suggest that standard enforcement legislation appears to have a greater effect on groups with historically low belt use, such as young people, males, passengers, and Black/African–Americans. When compared with other states that have made the change from secondary to standard enforcement, the increase in the safety belt use rate in Michigan was comparable to the increase seen in states with relatively high safety belt use prior to standard enforcement. However, states that had low safety belt use rates prior to adopting standard enforcement legislation observed a larger percentage point increase in the year following their change to standard enforcement.     

Getting Americans to buckle up: the efficacy of state seat belt laws

Annual state observed safety belt use rates over the period 1991–2001 are examined using time-series cross-section regression analysis. It was found that seat belt laws are associated with higher use rates and that the enforcement provision matters. Primary states experience belt use rates that on average are 9.1 percentage points higher than their secondary counterparts. In addition, the level of the fine imposed by statute has an effect on safety belt use apart from that attributable to the enforcement provision. The current median fine of $25 is associated with an additional 3.8 percentage points increase in belt use. To further increase safety belt use, it is recommended that states adopt primary enforcement and impose fines of at least $50 for violating a seat belt law.     

Primary enforcement seat belt laws are effective even in the face of rising belt use rates

A recent systematic literature review found that primary enforcement laws are more effective at increasing seat belt use than secondary laws in the United States. This report re-examines the studies included in the systematic review to explore whether the benefits of a primary law differ based on: (1) the baseline seat belt use rate; or (2) whether or not the primary law replaces a secondary law. States that directly enacted primary laws showed larger increases in observed seat belt use (median increase of 33 percentage points). These laws were enacted in the mid-1980s, when baseline belt use rates were below 35%. Smaller, but substantial increases in belt use were observed in states that replaced secondary with primary laws (median increase of 14 percentage points). Baseline belt use rates in these states ranged from 47 to 73%. Primary safety belt laws can further increase seat belt use even in states with relatively high baseline levels of belt use.     

Seat belt use among 13-15 year olds in primary and secondary enforcement law states

CONTEXT: Coverage and enforcement provisions of safety belt use laws vary by state. Most laws cover drivers and passengers age 16 and above. "Primary" enforcement laws allow police to stop and ticket a motorist for a safety belt law violation. With "secondary" enforcement laws, ticketing can only occur in the presence of another traffic infraction. Given the lower rates of restraint use among teen drivers and their passengers, the effect of primary enforcement laws on the restraint use of young teen passengers is of particular interest. OBJECTIVE: To compare restraint use by 13-15 year olds passengers in motor vehicle crashes in states with primary versus secondary enforcement safety belt laws. METHODS: Cross-sectional study of 3953 crashes involving 5372 children, representing 54,226 children aged 13-15 years in 41,198 crashes of insured vehicles in 16 states and Washington, DC between December 1, 1998 and December 31, 2004, with data collected via insurance claims records and a telephone survey. RESULTS: Non-use of restraints by 13-15 year olds was 7.2% (95% CI 4.3-10.1%) greater in secondary enforcement states (10.8%) as compared to states with primary enforcement laws (3.6%). After controlling for driver's age and restraint status and the seating row of the occupant, a 13-15 year olds was over twice as likely to be unrestrained in a secondary enforcement state as compared to a primary enforcement state (adjusted RR=2.2, 95% CI 1.5-3.1). CONCLUSIONS: States considering primary enforcement provisions to their restraint laws should consider the potential benefits these laws may have to all occupants in the vehicle, particularly young adolescents who are nearing driving age.     

Do states upgrading to primary enforcement of safety belt laws experience increased daytime and nighttime belt use?

As of 1 January 2007, 26 states and the District of Columbia have enacted primary enforcement of their safety belt laws, which allows law enforcement to stop motorists and cite them solely when they observe a vehicle occupant who is not wearing a safety belt. Interrupted time series analyses were used to determine whether six states which upgraded to primary enforcement laws experienced changes in nighttime (9:00 p.m. to 4:59 a.m.) and daytime (5:00 a.m. to 8:59 p.m.) safety belt use based on proxy estimates from fatal crash-involved vehicle occupants. Nighttime and daytime safety belt use increased in five of the six states after the primary enforcement laws were enacted. Because the methods used in these analyses reduced the likelihood that these increases resulted from preexisting secular trends towards increased belt use, the results provide strong support that upgrading from secondary to primary enforcement increases occupant safety belt use during both daytime and nighttime periods.     

Trends in driver and front-right passenger safety belt use in Michigan: 1984-1998

As part of Michigan’s effort to track trends in safety belt use within the state over time, the University of Michigan Transportation Research Institute conducted 20 statewide surveys of safety belt use between 1984 and 1998. Results indicate that Michigan safety belt use trends for drivers and front-right passengers are similar to other statewide and national trends. Belt use in Michigan increased dramatically immediately after the state implemented its mandatory belt use law (secondary enforcement) followed by a smaller decline that leveled off at a rate more than 20 percentage points higher than before the law. Belt use was consistently higher among drivers than front-right passengers, older than younger front-outboard occupants, females than males, and front-outboard occupants exiting freeways than those stopped at local intersections. Examination of belt use trends in Michigan provides useful information for continued efforts to increase belt use in our state and for all states interested in meeting national goals for safety belt use for the year 2000 and beyond.     

Characteristics of belted and unbelted drivers

Drivers who had been observed wearing or not wearing shoulder belts were compared using vehicle registration data, driver records, and telephone interviews. The observations were made on the New York Thruway during a special seat belt publicity and enforcement program, which achieved a 75% overall belt use. The results showed that those drivers who still did not wear a shoulder belt despite New York law and the special Thruway program were more likely to be male, to be driving older vehicles, to have more prior traffic convictions, to have more prior injury crash involvements, and to say they are more likely to take risks than others. Although drivers reported that assessing points against the drivers license for belt law violations could increase belt use, citations for belt use law violations were very rare, and enforcement would probably have to increase before any new penalty could be effective.     

An investigation of state population characteristics that moderate the relationship of state seat belt law and use in the United States

Objectives

Primary enforcement laws have been shown to be effective methods for increasing seat belt use at the state level.

Method

This study investigates state differences in the effectiveness of primary enforcement laws by assessing whether a state's academic achievement, health ranking, economic prosperity, violent crime rates, government effectiveness, gender distribution, or proportion of rural roads moderate the relationship between those laws and seat belt compliance rates.

Results

Aggregate state-level academic achievement, health ranking, government effectiveness, and proportion of rural roads uniquely moderated the seat belt use differences between primary and secondary enforcement states.

Conclusions

This evidence suggests that cultural, social, and demographic differences among regions may be important factors in explaining state-level differences in the effectiveness of primary enforcement of seat belt laws.     

The use of feedback signs to increase observed daytime seat belt use in two cities in North Carolina

Well publicized enforcement programs in North Carolina have raised seat belt use to about 80%. In an effort to find techniques to raise belt use further, signs providing feedback to drivers on belt use rates were introduced in two communities, Asheboro (population 18,000) and Greensboro (population 183,000). Feedback signs remind motorists about belt use and imply a constant and vigorous enforcement presence. The signs were prominently posted by the roadside at high volume locations; belt use information was changed weekly based on observational surveys. Observed daytime driver belt use in Asheboro increased from an average of 75% before the signs to 89% after the signs were established. At urban sites in Greensboro, driver belt use increased from 80% to 86%. Right front passenger belt use increased significantly in Asheboro but not in Greensboro. There were no changes in belt use at two interstate exit sites in Greensboro. Reasons for the differential success rates may relate to differences in initial belt use rates, community size, amount of publicity, and numbers of encounters with the signs. It is clear, however, that feedback signs can be an important supplement to belt use enforcement programs.     

Geographic and sociodemographic variation in self-reported seat belt use in the United States

Background

With new data available, we sought to update existing literature on the prevalence of self-reported seat belt use by state, region, and rural/urban status and to estimate the strength of the association between seat belt use and rural/urban status adjusted for type of seat belt law and several other factors.

Methods

We examined data on self-reported use of seat belts from 50 states, the District of Columbia, and three territories using the 2008 Behavioral Risk Factor Surveillance System, a state-based random-digit-dialed telephone survey (n = 406,552). Reported seat belt use was assessed by state, U.S. Census regions, and U.S. Department of Agriculture (USDA) rural/urban continuum codes.

Results

Overall, 85% of adults in the United States reported they always used seat belts. Regionally, the West had the highest prevalence of persons who reported that they always wear seat belts (89.6%) and the Midwest had the lowest (80.4%). States with primary seat belt laws had the highest prevalence of reported seat belt use, compared with states with secondary or no laws. After adjusting for various sociodemographic characteristics, body mass index, and type of seat belt law, persons in the most densely populated metropolitan areas were significantly more likely to report always wearing seat belts than those in most sparsely populated rural areas (adjusted odds ratio = 2.9).

Conclusion

Our findings reinforce the evidence that primary enforcement seat belt laws are effective for increasing seat belt use, and suggest that upgrading to primary enforcement laws will be an important strategy for reducing crash-related fatalities in rural areas.     

Predictors of safety belt use among crash-involved drivers and front seat passengers: adjusting for over-reporting

Police-reported crash data are rarely used to investigate safety belt use and its predictors, even though these data have a number of advantages over data collected in roadside surveys. It has been widely recognized that motorists tend to over-report their safety belt use to police when mandatory belt use becomes law. In this paper, we use a logistic regression model that allows for misclassification errors in outcome variable to examine predictors of safety belt use among crash-involved drivers and front seat passengers. Our analysis shows significant associations between occupant characteristics, driving circumstances, and safety belt use. Alcohol involvement has the strongest negative association with safety belt use, but this association would be considerably underestimated without adjusting for the over-reporting of safety belt use in police-reported crash data. The adjusted belt use rate among front seat occupants with at least nonincapacitating injuries is about 81%, compared to 90% in police-reported crash data.     

A comparison of safety belt use between commercial and noncommercial light-vehicle occupants

The purpose of this study was to conduct an observational survey of safety belt use to determine the use rate of commercial versus noncommercial light-vehicle occupants. Observations were conducted on front-outboard vehicle occupants in eligible commercial and noncommercial vehicles in Michigan (i.e.. passenger cars, vans/minivans, sport-utility vehicles, and pickup trucks). Commercial vehicles that did not fit into one of the four vehicle type categories, such as tractor-trailers, buses, or heavy trucks, were not included in the survey. The study found that the restraint use rate for commercial light-vehicle occupants was 55.8% statewide. The statewide safety belt use rate for commercial light-vehicles was significantly lower than the rate of 71.2% for noncommercial light-vehicles. The safety belt use rate for commercial vehicles was also significantly different as a function of region, vehicle type, seating position, age group, and road type. The results provide important preliminary data about safety belt use in commercial versus noncommercial light-vehicles and indicate that further effort is needed to promote safety belt use in the commercial light-vehicle occupant population. The study also suggests that additional research is required in order to develop effective programs that address low safety belt use in the commercial light-vehicle occupant population.     

Effects of enforcement intensity on alcohol impaired driving crashes

Background

Research measuring levels of enforcement has investigated whether increases in police activities (e.g., checkpoints, driving-while-intoxicated [DWI] special patrols) above some baseline level are associated with reduced crashes and fatalities. Little research, however, has attempted to quantitatively measure enforcement efforts and relate different enforcement levels to specific levels of the prevalence of alcohol-impaired driving.

Objective

The objective of this study was to investigate the effects of law-enforcement intensity in a sample of communities on the rate of crashes involving a drinking driver. We analyzed the influence of different enforcement strategies and measures: (1) specific deterrence – annual number of driving-under-the-influence (DUI) arrests per capita; (2) general deterrence – frequency of sobriety checkpoint operations; (3) highly visible traffic enforcement – annual number of traffic stops per capita; (4) enforcement presence – number of sworn officers per capita; and (5) overall traffic enforcement – the number of other traffic enforcement citations per capita (i.e., seat belt citations, speeding tickets, and other moving violations and warnings) in each community.

Methods

We took advantage of nationwide data on the local prevalence of impaired driving from the 2007 National Roadside Survey (NRS), measures of DUI enforcement activity provided by the police departments that participated in the 2007 NRS, and crashes from the General Estimates System (GES) in the same locations as the 2007 NRS. We analyzed the relationship between the intensity of enforcement and the prevalence of impaired driving crashes in 22–26 communities with complete data. Log-linear regressions were used throughout the study.

Results

A higher number of DUI arrests per 10,000 driving-aged population was associated with a lower ratio of drinking-driver crashes to non-drinking-driver crashes (p = 0.035) when controlling for the percentage of legally intoxicated drivers on the roads surveyed in the community from the 2007 NRS. Results indicate that a 10% increase in the DUI arrest rate is associated with a 1% reduction in the drinking driver crash rate. Similar results were obtained for an increase in the number of sworn officers per 10,000 driving-age population.

Discussion

While a higher DUI arrest rate was associated with a lower drinking-driver crash rate, sobriety checkpoints did not have a significant relationship to drinking-driver crashes. This appeared to be due to the fact that only 3% of the on-the-road drivers were exposed to frequent sobriety checkpoints (only 1 of 36 police agencies where we received enforcement data conducted checkpoints weekly). This low-use strategy is symptomatic of the general decline in checkpoint use in the U.S. since the 1980s and 1990s when the greatest declines in alcohol-impaired-driving fatal crashes occurred. The overall findings in this study may help law enforcement agencies around the country adjust their traffic enforcement intensity in order to reduce impaired driving in their community.     

Active transportation: Do current traffic safety policies protect non-motorists?

Objective

This study investigated the impact that state traffic safety regulations have on non-motorist fatality rates.

Methods

Data obtained from the National Highway Traffic Safety Administration (NHTSA), the Federal Highway Administration (FHWA), and the National Institute on Alcohol Abuse and Alcoholism (NIAAA) were analyzed through a pooled time series cross-sectional model using fixed effects regression for all 50 states from 1999 to 2009. Two dependent variables were used in separate models measuring annual state non-motorist fatalities per million population, and the natural log of state non-motorist fatalities. Independent variables measuring traffic policies included state expenditures for highway law enforcement and safety per capita; driver cell phone use regulations; graduated driver license regulations; driver blood alcohol concentration regulations; bike helmet regulations; and seat belt regulations. Other control variables included percent of all vehicle miles driven that are urban and mean per capita alcohol consumption per year.

Results

Non-motorist traffic safety was positively impacted by state highway law enforcement and safety expenditures per capita, with a decrease in non-motorist fatalities occurring with increased spending. Per capita consumption of alcohol also influenced non-motorist fatalities, with higher non-motorist fatalities occurring with higher per capita consumption of alcohol. Other traffic safety covariates did not appear to have a significant impact on non-motorist fatality rates in the models.

Conclusion

Our research suggests that increased expenditures on state highway and traffic safety and the initiation/expansion of programs targeted at curbing both driver and non-motorist intoxication are a starting point for the implementation of traffic safety policies that reduce risks for non-motorists.     

Lotka's law reconsidered: The evolution of publication and citation distributions in scientific fields

This paper reports early steps in research that seeks to clarify how publications of scientists interact dynamically with citations and reputation in shaping the evolution of scientific fields. We assume that Lotka's modified law holds for scientific fields. A primary approach to model publication productivity was published by Yablonsky. In contrast to Yablonsky's unfinished mathematical approach, our simulation approach is not predominantly driven by insight into the formal generation mechanisms of certain processes but more theory driven. It considers the evolution of publication and citation distributions over the histories of scientific fields using both simulated and real historical data.     

Citation frequency: A biased measure of research impact significantly influenced by the geographical origin of research articles

Context. The use of citation frequency and impact factor as measures of research quality and journal prestige is being criticized. Citation frequency is augmented by self-citation and for most journals the majority of citations originate from a minority of papers. We hypothesized that citation frequency is also associated with the geographical origin of the research publication. Objective. We determined whether citations originate more frequently from institutes that are located in the same country as the authors of the cited publication than would be expected by chance. Design. We screened citations referring to 1200 cardiovascular publications in the 7 years following their publication. For the 1200 citation recipient publications we documented the country where the research originated (9 countries/regions) and the total number of received citations. For a selection of 8864 citation donor papers we registered the country/region where the citing paper originated. Results. Self-citation was common in cardiovascular journals (n = 1534, 17.8%). After exclusion of self-citation, however, the number of citations that originated from the same country as the author of the citation recipient was found to be on average 31.6% higher than would be expected by chance (p<0.01 for all countries/regions). In absolute numbers, nation oriented citation bias was most pronounced in the USA, the country with the largest research output (p<0.001). Conclusion. Citation frequency was significantly augmented by nation oriented citation bias. This nation oriented citation behaviour seems to mainly influence the cumulative citation number for papers originating from the countries with a larger research output.     

Patents cited in the scientific literature: An exploratory study of 'reverse' citation relations

This paper reports on a new approach to study the linkage between science and technology. Unlike most contributions to this area we do not trace citations of scientific literature in patents but explore citations of patents in scientific literature. Our analysis is based on papers recorded in the 1996-2000 annual volumes of the CD-Edition of Science Citation Index (SCI) of the Institute for Scientific Information (ISI) and patent data provided by the US Patent and Trademark Office. Almost 30,000 US patents were cited by scientific research papers. We analysed the citation links by scientific fields and technological sectors. Chemistry-related subfields tended to cite patents more than other scientific area. Among technological sectors, chemical clearly dominates followed by drugs and medical patents as the most frequently cited categories. Further analyses included a country-ranking based on inventor-addresses of the cited patents, a more detailed inspection of the ten most cited patents, and an analysis of class-field transfers. The paper concludes with the suggestions for future research. One of them is to compare our 'reverse' citation data with 'regular' patent citation data within the same classification system to see whether citations occur, irrespectively of their directionality, in the same fields of science and technology. Another question is as to how one should interpret reverse citation linkages.