Parental influence on adolescent compliance with graduated driver licensing conditions and crashes as a restricted licensed driver: New Zealand Drivers Study

Aim

To examine the influence of parental knowledge of, and support for graduated driver licensing (GDL) conditions, parental management of adolescent driving and parental driving behaviour on adolescent compliance with GDL conditions and crashes as a restricted licence driver.

Method

This research was part of the New Zealand Drivers Study (NZDS), a prospective cohort study of 3992 newly licensed car drivers. NZDS participants were recruited at the learner licence stage, with follow-up aligned with the GDL stages. At the restricted licence stage 1200 parents of NZDS adolescents, aged 15–17 years at learner licensure, were recruited and completed interviews. 895 of these adolescents progressed to their full licence and completed the full licence interview. These 895 parent–adolescent pairs were the study population in this research. Topics examined included parental knowledge of, and support for GDL conditions, management of adolescent driving (driving rules, adolescent vehicle ownership, delaying licensure), and their own driving behaviours. Outcomes examined were adolescent compliance with GDL restricted licence conditions (night-time and passenger), and crashes as a driver during the restricted licence stage.

Results

After controlling for other variables, factors independently associated with adolescent low compliance with GDL conditions were: low parental knowledge of conditions, parents’ implementing few driving rules, adolescent vehicle ownership, and parent crash involvement. Factors independently associated with adolescents being a crash involved driver were: parents’ actively delaying licensure, adolescent vehicle ownership, and parent crash involvement.

Conclusion

There is increasing recognition of the importance of parental involvement in adolescent driving. The results show that parents are influential in determining adolescent compliance with GDL and risk of crash. Parents can have considerable positive influence on their adolescent's driving through ensuring compliance with the components of GDL, limiting vehicle ownership and by modelling safe driving behaviours.     

The characteristics of young pre-licensed drivers: Evidence from the New Zealand Drivers Study

Aim

The aim of this study was to identify demographic and behavioural factors associated with pre-licensed driving.

Method

A cohort comprising 3526 newly licensed drivers aged 15–24 years old from throughout New Zealand completed a questionnaire which sought information on pre-licensed driving behaviour and factors thought to be related to this.

Results

Almost half of the participants had driven on-road prior to passing their learner license theory test; 14% had driven more than 20 times; and 7.5% had driven more than 200 km. Multivariate logistic regression showed the results differed depending on the outcome examined. In general pre-licensed driving was significantly higher among males, among Māori, those living in a rural area, and those living in an area of high deprivation. Furthermore, those who drove pre-licensed were more likely to engage in other risky behaviours such as hazardous drinking and cannabis use, and have medium to high scores for sensation seeking and aggression/hostility.

Conclusion

The young people who were pre-licensed drivers displayed a range of demographic and behavioural characteristics that indicate they may be at higher crash risk than their peers who did not drive before licensing. Identifying those who drive before licensing and targeting road safety interventions towards this group may help reduce the high crash risk among novice drivers.     

Unsupervised driving by learner licence holders: Associated characteristics and crash risk

Aims

To determine: (a) the association between socio-demographic, and behavioural factors and compliance with supervised driving condition as a learner licensed driver, (b) whether unsupervised driving as a learner licence holder was associated with elevated crash risk while holding a learner licence.

Study design

The study population was the New Zealand Drivers Study (NZDS) cohort, a prospective cohort study designed to explore the relationship between a comprehensive range of driving and traffic safety related factors and subsequent traffic crashes and convictions among newly licensed drivers.

Results

Thirty-one percent of the study sample was non-compliant at least once with the supervised driving condition. Many socio-demographic and behavioural risk factors were independently associated with unsupervised driving. The strength of the associations was greatest for those with relatively high levels of unsupervised driving (13+ trips). High distance driven showed the strongest relationship: RR 8.91 (95% CI 5.27–15.07). Unsupervised driving was associated with increased risk of crash: 1–12 trips: RR 1.84 (1.29–2.61), and 13+ trips: RR 2.71 (1.94–3.80).Given that a significant portion of learner licence holders report driving unsupervised and those that violate this condition the most are more likely to crash, evaluation of strategies designed at improving compliance with learner licence supervised driving condition should be a research priority.     

Young driver crash rates by licensing age,driving experience,and license phase

Background

Few studies have concurrently assessed the influence of age and experience on young driver crashes, in particular in the post-Graduated Driver Licensing (GDL) era. Further, little attention is given to the transition from intermediate to full licensure. We examined the independent and joint contributions of licensing age, driving experience, and GDL license phase on crash rates among the population of young New Jersey (NJ) drivers.

Methods

From a unique linked database containing licensing and crash data, we selected all drivers who obtained their NJ intermediate license at 17–20 years old from 2006–2009 (n = 410,230). We determined the exact age at which each driver obtained an intermediate and full license and created distinct, fixed cohorts of drivers based on their age at intermediate licensure. For each cohort, we calculated and graphed observed monthly crash rates over the first 24 months of licensure. Further, we examined crash rates by age at licensure, driving experience (i.e., time since licensure), and license phase.

Results

First-month crash rates were higher among the youngest drivers (licensed at 17y0m). Drivers who were licensed later experienced a reduced “steepness” in the slope of their crash rates in the critical initial months of driving, but there did not appear to be any incremental benefit of later licensure once drivers had six months of driving experience. Further, at each age, those with more driving experience had lower crash rates; however, the benefit of increased experience was greatest for the substantial proportion of teens licensed immediately after becoming eligible (at 17y0m). Finally, independent of age and experience, teen drivers’ crash risk increased substantially at the point of transition to a full license, while drivers of a similar age who remained in the intermediate phase continued to experience a decline in crash rates.

Conclusion

Age and driving experience interact to influence crash rates. Further, independent of these two factors, there is an abrupt increase in crash risk at the point of transition from intermediate to full licensure. Future studies should investigate whether this increase is accounted for by a change in driving exposure, driving behaviors, and/or other factors.     

The effect of the learner license Graduated Driver Licensing components on teen drivers’ crashes

Background

Most studies evaluating the effectiveness of Graduated Driver Licensing (GDL) have focused on the overall system. Studies examining individual components have rarely accounted for the confounding of multiple, simultaneously implemented components. The purpose of this paper is to quantify the effects of a required learner license duration and required hours of supervised driving on teen driver fatal crashes.

Methods

States that introduced a single GDL component independent of any other during the period 1990–2009 were identified. Monthly and quarterly fatal crash rates per 100,000 population of 16- and 17-year-old drivers were analyzed using single-state time series analysis, adjusting for adult crash rates and gasoline prices. Using the parameter estimates from each state's time series model, the pooled effect of each GDL component on 16- and 17-year-old drivers’ fatal crashes was estimated using a random effects meta-analytic model to combine findings across states.

Results

In three states, a six-month minimum learner license duration was associated with a significant decline in combined 16- and 17-year-old drivers’ fatal crash rates. The pooled effect of the minimum learner license duration across all states in the sample was associated with a significant change in combined 16- and 17-year-old driver fatal crash rates of −.07 (95% Confidence Interval [CI] −.11, −.03). Following the introduction of 30 h of required supervised driving in one state, novice drivers’ fatal crash rates increased 35%. The pooled effect across all states in the study sample of having a supervised driving hour requirement was not significantly different from zero (.04, 95% CI −.15, .22).

Conclusion

These findings suggest that a learner license duration of at least six-months may be necessary to achieve a significant decline in teen drivers’ fatal crash rates. Evidence of the effect of required hours of supervised driving on teen drivers’ fatal crash rates was mixed.     

Fatal crash involvement of unlicensed young drivers: County level differences according to material deprivation and urbanicity in the United States

Objectives

This study assessed the association between county level material deprivation and urbanization with fatal road traffic crashes involving young unlicensed drivers in the United States (US).

Background

Road traffic crashes have been positively associated with area deprivation and low population density but thus far few studies have been concerned specifically with young drivers, especially those that are unlicensed.

Methods

A county material deprivation index was derived from the Townsend Material Deprivation Index, with variables extracted from the US Census (2000). An urbanicity scale was adapted from the US Department of Agriculture's Rural–Urban Continuum Codes (2003). Data on fatal crashes involving a young unlicensed driver during a seven-year period (2000–2006; n = 3059) were extracted from the Fatality Analysis Reporting System. The effect of deprivation and urbanicity on the odds of the occurrence of at least one fatal crash at the county level was modeled by conditional and unconditional logistic regression.

Results

The conditional model found a positive association between material deprivation and a fatal crash involving a young unlicensed driver (OR = 1.19, 95% CI 1.17, 1.21). The interaction between urbanicity and material deprivation was negatively associated in suburban counties for fatal crashes (OR = 0.92, 95% CI 0.90, 0.95).

Conclusions

An association with material deprivation and the likelihood of a fatal crash involving a young unlicensed driver is a new finding. It can be used to inform specific county-level interventions and promote state licensing policies to provide equity in young people's mobility regardless of where they live.     

Pregnant driver-associated motor vehicle crashes in North Carolina, 2001–2008

Background

Motor vehicle crashes are the leading cause of maternal injury-related mortality during pregnancy in the United States, yet pregnant women remain an understudied population in motor vehicle safety research.

Methods

We estimated the risk of being a pregnant driver in a crash among 878,546 pregnant women, 16–46 years, who reached the 20th week of pregnancy in North Carolina (NC) from 2001 to 2008. We also examined the circumstances surrounding the crash events. Pregnant drivers in crashes were identified by probabilistic linkage of live birth and fetal death records and state motor vehicle crash reports.

Results

During the 8-year study period, the estimated risk of being a driver in a crash was 12.6 per 1000 pregnant women. Pregnant women at highest risk of being drivers in serious crashes were 18–24 years old (4.5 per 1000; 95% confidence interval, CI,4.3, 4.7), non-Hispanic black (4.8 per 1000; 95% CI = 4.5, 5.1), had high school diplomas only (4.5 per 1000; 95% CI = 4.2, 4.7) or some college (4.1 per 1000; 95% CI = 3.9, 4.4), were unmarried (4.7 per 1000; 95% CI = 4.4, 4.9), or tobacco users (4.5 per 1000; 95% CI = 4.1, 5.0). A high proportion of crashes occurred between 20 and 27 weeks of pregnancy (45%) and a lower proportion of crashes involved unbelted pregnant drivers (1%) or airbag deployment (10%). Forty percent of crashes resulted in driver injuries.

Conclusions

NC has a relatively high pregnant driver crash risk among the four U.S. states that have linked vital records and crash reports to examine pregnancy-associated crashes. Crash risks were especially elevated among pregnant women who were young, non-Hispanic black, unmarried, or used tobacco. Additional research is needed to quantify pregnant women's driving frequency and patterns.     

Confirmatory factor analysis of the Behaviour of Young Novice Drivers Scale (BYNDS)

Purpose

The greatly increased risk of being killed or injured in a car crash for the young novice driver has been recognised in the road safety and injury prevention literature for decades. Risky driving behaviour has consistently been found to contribute to traffic crashes. Researchers have devised a number of instruments to measure this risky driving behaviour. One tool developed specifically to measure the risky behaviour of young novice drivers is the Behaviour of Young Novice Drivers Scale (BYNDS) (Scott-Parker et al., 2010). The BYNDS consists of 44 items comprising five subscales for transient violations, fixed violations, misjudgement, risky driving exposure, and driving in response to their mood. The factor structure of the BYNDS has not been examined since its development in a matched sample of 476 novice drivers aged 17–25 years.

Method

The current research attempted to refine the BYNDS and explore its relationship with the self-reported crash and offence involvement and driving intentions of 390 drivers aged 17–25 years (M = 18.23, SD = 1.58) in Queensland, Australia, during their first 6 months of independent driving with a Provisional (intermediate) driver's licence. A confirmatory factor analysis was undertaken examining the fit of the originally proposed BYNDS measurement model.

Results

The model was not a good fit to the data. A number of iterations removed items with low factor loadings, resulting in a 36-item revised BYNDS which was a good fit to the data. The revised BYNDS was highly internally consistent. Crashes were associated with fixed violations, risky driving exposure, and misjudgement; offences were moderately associated with risky driving exposure and transient violations; and road-rule compliance intentions were highly associated with transient violations.

Conclusions

Applications of the BYNDS in other young novice driver populations will further explore the factor structure of both the original and revised BYNDS. The relationships between BYNDS subscales and self-reported risky behaviour and attitudes can also inform countermeasure development, such as targeting young novice driver non-compliance through enforcement and education initiatives.     

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.     

Risky driving behavior among university students and staff in the Sultanate of Oman

Background

There is a well developed literature on research investigating the relationship between various driving behaviors and road crash involvement. However, this research has predominantly been conducted in developed economies dominated by western types of cultural environments. To date no research has been published that has empirically investigated this relationship within the context of the emerging economies such as Oman.

Objective

The present study aims to investigate driving behavior as indexed in the driving behavior questionnaire (DBQ) among a group of Omani university students and staff.

Methods

A convenience non-probability self-selection sampling approach was utilized with Omani university students and staff.

Results

A total of 1003 Omani students (n = 632) and staff (n = 371) participated in the survey. Factor analysis of the BDQ revealed four main factors that were errors, speeding violation, lapses and aggressive violation. In the multivariate logistic backward regression analysis, the following factors were identified as significant predictors of being involved in causing at least one crash: driving experience, history of offenses and two DBQ components, i.e., errors and aggressive violation.

Conclusion

This study indicates that errors and aggressive violation of the traffic regulations as well as history of having traffic offenses are major risk factors for road traffic crashes among the sample. While previous international research has demonstrated that speeding is a primary cause of crashing, in the current context, the results indicate that an array of factors is associated with crashes. Further research using more rigorous methodology is warranted to inform the development of road safety countermeasures in Oman that improves overall Traffic Safety Culture.     

On-road bicycle facilities and bicycle crashes in Iowa, 2007–2010

Purpose

An average of 611 deaths and over 47,000 bicyclists are injured in traffic-related crashes in the United States each year. Efforts to increase bicycle safety are needed to reduce and prevent injuries and fatalities, especially as trends indicate that ridership is increasing rapidly. The objective of this study was to evaluate the effect of bicycle-specific roadway facilities (e.g., signage and bicycle lanes) in reducing bicycle crashes.

Methods

We conducted a case site-control site study of 147 bicycle crash-sites identified from the Iowa Department of Transportation crash database from 2007 to 2010 and 147 matched non-crash sites. Control sites were randomly selected from intersections matched to case sites on neighborhood (census block group) and road classification (arterial, feeder, collector, etc.). We examined crash risk by any on-road bicycle facility present and by facility type (pavement markings--bicycle lanes and shared lane arrows, bicycle-specific signage, and the combination of markings and signage), controlling for bicycle volume, motor vehicle volume, street width, sidewalks, and traffic controls.

Results

A total of 11.6% of case sites and 15.0% of controls had an on-road bicycle facility. Case intersections had higher bicycle volume (3.52 vs. 3.34 per 30 min) and motor vehicle volume (248.77 vs. 205.76 per 30 min) than controls. Our results are suggestive that the presence of an on-road bicycle facility decreases crash risk by as much as 60% with a bicycle lane or shared lane arrow (OR = 0.40, 95% CI = 0.09–1.82) and 38% with bicycle-specific signage (OR = 0.62, 95% CI = 0.15–2.58).

Conclusions

Investments in bicycle-specific pavement markings and signage have been shown to be beneficial to traffic flow, and our results suggest that they may also reduce the number of bicycle-motor vehicle crashes and subsequent injuries and fatalities. As a relatively low-cost traffic feature, community considerations for further implementation of these facilities are justified.     

Crash fatality risk and unibody versus body-on-frame structure in SUVs

Background

In crashes between cars and SUVs, car occupants are more likely to be killed than if they crashed with another car. An increasing proportion of SUVs are built with unibody, rather than truck-like body-on-frame construction. Unibody SUVs are generally lighter, less stiff, and less likely to roll over than body-on-frame SUVs, but whether unibody structure affects risk of death in crashes is unknown.

Objective

To determine whether unibody SUVs differ from body-on-frame SUVs in the danger they pose to occupants of other vehicles and in the self-protection they offer to their own occupants.

Methods

Case–control study of crashes between one compact SUV and one other passenger vehicle in the US during 1995–2008, in which the SUV was model year 1996–2006. Cases were all decedents in fatal crashes, one control was selected from each non-fatal crash.

Findings

Occupants of passenger vehicles that crashed with compact unibody SUVs were at 18% lower risk of death compared to those that crashed with compact body-on-frame SUVs (adjusted odds ratio 0.82 (95% confidence interval 0.73–0.94)). Occupants of compact unibody SUVs were also at lower risk of death compared to occupants of body-on-frame SUVs (0.86 (0.72–1.02)).

Conclusions

In two-vehicle collisions involving compact SUVs, unibody structure was associated with lower risk of death both in occupants of other vehicles in the crash, and in SUVs’ own occupants.     

Older drivers’ crashes in Queensland,Australia

Background

The growing proportion of older adults in Australia is predicted to comprise 23% of the population by 2030. Accordingly, an increasing number of older drivers and fatal crashes of these drivers could also be expected. While the cognitive and physiological limitations of ageing and their road safety implications have been widely documented, research has generally considered older drivers as a homogeneous group. Knowledge of age-related crash trends within the older driver group itself is currently limited.

Objective

The aim of this research was to identify age-related differences in serious road crashes of older drivers. This was achieved by comparing crash characteristics between older and younger drivers and between sub-groups of older drivers. Particular attention was paid to serious crashes (crashes resulting in hospitalisation and fatalities) as they place the greatest burden on the Australian health system.

Method

Using Queensland Crash data, a total of 191,709 crashes of all-aged drivers (17–80+) over a 9-year period were analysed. Crash patterns of drivers’ aged 17–24, 25–39, 40–49, 50–59, 60–69, 70–79 and 80+ were compared in terms of crash severity (e.g., fatal), at fault levels, traffic control measures (e.g., stop signs) and road features (e.g., intersections). Crashes of older driver sub-groups (60–69, 70–79, 80+) were also compared to those of middle-aged drivers (40–49 and 50–59 combined, who were identified as the safest driving cohort) with respect to crash-related traffic control features and other factors (e.g., speed). Confounding factors including speed and crash nature (e.g., sideswipe) were controlled for.

Results and discussion

Results indicated that patterns of serious crashes, as a function of crash severity, at-fault levels, road conditions and traffic control measures, differed significantly between age groups. As a group, older drivers (60+) represented the greatest proportion of crashes resulting in fatalities and hospitalisation, as well as those involving uncontrolled intersections and failure to give way. The opposite was found for middle-aged drivers, although they had the highest proportion of alcohol and speed-related crashes when compared to older drivers. Among all older drivers, those aged 60–69 were least likely to be involved in or the cause of crashes, but most likely to crash at interchanges and as a result of driving while fatigued or after consuming alcohol. Drivers aged 70–79 represented a mid-range level of crash involvement and culpability, and were most likely to crash at stop and give way signs. Drivers aged 80 years and beyond were most likely to be seriously injured or killed in, and at-fault for, crashes, and had the greatest number of crashes at both conventional and circular intersections. Overall, our findings highlight the heterogeneity of older drivers’ crash patterns and suggest that age-related differences must be considered in measures designed to improve older driver safety.     

Trends in older driver crash involvement rates and survivability in the United States: An update

Objective

Previous research has shown that fatal crash involvement rates per licensed driver aged 70 and older declined significantly more per year in the United States than rates for middle-aged drivers aged 35–54 during 1997–2008, and per vehicle mile traveled from 1995–1996 to 2001–2002. Analyses of police-reported crash data during 1997–2005 indicated that the greater declines for older drivers were due to decreases in crash involvement and in the risk of dying in the crashes that occurred. The current study examined if trends in crash rates, crash involvements, and survivability persisted into more recent years.

Methods

Trends for drivers 70 and older were compared with trends for drivers aged 35–54 for U.S. national fatal passenger vehicle crash involvements per 100,000 licensed drivers during 1997–2012 and for U.S. national fatal passenger vehicle crash involvements per vehicle miles traveled in 1995–1996, 2001–2002, and 2008. Using police-reported crash data during 1997–2008 from 20 U.S. states, trends in involvement rates in non-fatal crashes of various severities per 100,000 licensed drivers and changes in the odds of death and the odds of death or serious injury in a crash were compared between older and middle-aged drivers.

Results

During 2007–2012, declines in national fatal crash involvement rates per licensed driver were similar for drivers 70 and older and middle-aged drivers (18 percent each). However, when considering the entire study period, fatal crash involvement rates continued to reflect a substantially larger decline for drivers 70 and older than for middle-aged drivers (42 vs. 30 percent per licensed driver during 1997–2012, 39 vs. 26 percent per vehicle mile traveled from 1995–2006 to 2008). When analyses of police-reported crash data were extended through 2008, non-fatal injury crash involvement rates per licensed driver declined more for older than for middle-aged drivers (39 vs. 30 percent), and unlike in prior research, average annual declines were significantly larger for drivers 80 and older. Property damage-only crash involvement rates similarly declined significantly more for older than for middle-aged drivers (15 vs. 3 percent). Drivers 70 and older in 1997 were 3.5 times more likely than middle-aged drivers to die in a crash, and this ratio declined to 3.2 by 2008.

Conclusions

Although declines in fatal crash involvement rates in recent years have not differed between older and middle-aged drivers, this did not undo earlier gains for older drivers. The recent slowing in the relative magnitude of the decline for older drivers may be related to the differential effect of the U.S. recession on fatal crash involvements of drivers in these age groups. The decreased likelihood of being involved in a crash of any severity and increased survivability when a crash occurred held when examining data through 2008, and for drivers 80 and older, significant declines in crash involvement relative to middle-aged drivers extended to non-fatal injury crashes.     

Not just a rural occurrence: Differences in agricultural equipment crash characteristics by rural–urban crash site and proximity to town

Purpose

Although approximately one-third of agricultural equipment-related crashes occur near town, these crashes are thought to be a rural problem. This analysis examines differences between agricultural equipment-related crashes by their urban–rural distribution and distance from a town.

Methods

Agricultural equipment crashes were collected from nine Midwest Departments of Transportation (2005–2008). Crash zip code was assigned as urban or rural (large, small and isolated) using Rural–Urban Commuting Areas. Crash proximity to a town was estimated with ArcGIS. Multivariable logistic regression was used to estimate the odds of crashing in an urban versus rural zip codes and across rural gradients. ANOVA analysis estimated mean distance (miles) from a crash site to a town.

Findings

Over four years, 4444 crashes involved agricultural equipment. About 30% of crashes occurred in urban zip codes. Urban crashes were more likely to be non-collisions (aOR = 1.69[1.24–2.30]), involve ≥2 vehicles (2 vehicles: aOR = 1.58[1.14–2.20], 3+ vehicles: aOR = 1.68[0.98–2.88]), occur in a town (aOR = 2.06[1.73–2.45]) and within one mile of a town (aOR = 1.65[1.40–1.95]) than rural crashes. The proportion of crashes within a town differed significantly across rural gradients (P < 0.0001). Small rural crashes, compared to isolated rural crashes, were 1.98 (95%CI[1.28–3.06]) times more likely to be non-collisions. The distance from the crash to town differed significantly by the urban-rural distribution (P < 0.0001).

Conclusions

Crashes with agricultural equipment are unexpectedly common in urban areas and near towns and cities. Education among all roadway users, increased visibility of agricultural equipment and the development of complete rural roads are needed to increase road safety and prevent agricultural equipment-related crashes.     

Will the light truck bumper height-matching standard reduce deaths in cars?

Background

In a collision between a car and a sport utility vehicle (SUV) or pickup truck, car occupants are more likely to be killed than if they crashed with another car. Some of the excess risk may be due to the propensity of SUVs and pickups with high bumpers to override the lower bumpers in cars. To reduce this incompatibility, particularly in head-on collisions, in 2003 automobile manufacturers voluntarily established a bumper height-matching standard for pickups and SUVs.

Objective

To assess whether height-matching bumpers in pickups and SUVs were associated with the risk of death in either car occupants or pickup and SUV occupants.

Methods

Case–control study of collisions between one car and one SUV or pickup in the US during 2000–2008, in which the SUV or pickup was model year 2000–2006. Cases were all decedents in fatal crashes; one control was selected from each crash in a national probability sample of crashes.

Findings

Occupants of cars that crashed with SUVs or pickups with height-matching bumpers may be at slightly reduced risk of death compared to those that crashed with other SUVs or pickups (adjusted odds ratio: 0.83 (95% confidence interval 0.61–1.13)). There was no evidence of a reduction in risk in head-on crashes (1.09 (0.66–1.79)). In crashes in which the SUV or pickup struck the car on the side, height-matched bumpers were associated with a reduced risk of death (0.68 (0.48–0.97)). Occupants of SUVs and pickups with height-matching bumpers may also be at slightly reduced risk of death (0.91 (0.64–1.28)).

Conclusions

Height-matching bumpers were associated with a reduced risk of death among car occupants in crashes in which SUVs or pickups struck cars in the side, but there was little evidence of an effect in head-on crashes. The new bumper height-matching standard may not achieve its primary goal of reducing deaths in head-on crashes, but may modestly reduce overall deaths in crashes between cars and SUVs or pickups because of unanticipated benefits to car occupants in side crashes, and a possible beneficial effect to SUV and pickup occupants.     

Crash risk factors related to individuals sustaining and drivers following traumatic brain injuries

Objective

Some crashes result in drivers experiencing (or sustaining) a traumatic brain injury (TBI) while other crashes involve drivers that have already experienced a TBI. The objective of this study is to examine the factors that influence these two TBI crash groups.

Methods

Data from the Iowa Department of Public Health's Brain Injury Registry and Department of Transportation's crash records were linked together and used in logistic regression models to predict the likelihood of a driver sustaining a TBI in a crash and those who drive after a TBI.

Results

Between 2001 and 2006, there were 2382 crashes in which an individual sustained a TBI. As expected, a higher likelihood of sustaining a TBI was observed for motorcycle drivers who did not wear a helmet and in crashes that resulted in total or disabling vehicle damage. Focusing specifically on the post-TBI drivers (and not occupants), 1583 were involved in crashes. These post-TBI drivers were less likely to wear seatbelts or have passengers in the vehicle at the time of the crash, and were more likely to crash at night. Post-TBI drivers were also involved in significantly more multiple crashes (about 14%) when compared to drivers who have not experienced a TBI (about 10%) during the study period. When controlling for gender, date of injury, and severity of TBI (using Glasgow Coma Scale), individuals that sustained a TBI when they were younger were more likely to be involved in multiple crashes.

Conclusions

Different factors influence the crash likelihood for those that sustain a TBI in a crash and those that crash following a TBI. In general, post-TBI drivers have a higher occurrence of multiple crashes and this should be further explored to guide driver rehabilitation, evaluation, and training.