Risk Of Fatal Crash Involvement Research Articles

Prescription opioids, alcohol and fatal motor vehicle crashes: a population-based case-control study

BackgroundThe prevalence of prescription opioid use among drivers has increased markedly in the past two decades. The purpose of this study is to assess the associations of prescription opioid use and alcohol use with the risk of fatal crash involvement in US drivers.MethodsWe performed a population-based case-control study using toxicological testing data from two national data systems. Cases (n = 3606) were drivers involved in fatal motor vehicle crashes selected from the Fatality Analysis Reporting System and controls (n = 15,600) were drivers participating in the 2007 and 2013 National Roadside Surveys of Alcohol and Drug Use by Drivers. Multivariable logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs) of fatal crash involvement associated with prescription opioid use with and without the presence of alcohol.ResultsOverall, cases were significantly more likely than controls to test positive for prescription opioids (5.0% vs. 3.7%, p < 0.001), alcohol (56.2% vs. 7.1%, p < 0.0001), and both substances (2.2% vs. 0.2%, p < 0.001). Relative to drivers testing negative for prescription opioids and alcohol, the adjusted ORs of fatal crash involvement were 1.72 (95% CI: 1.37, 2.17) for those testing positive for prescription opioids and negative for alcohol, 17.92 (95% CI: 16.19, 19.84) for those testing positive for alcohol and negative for prescription opioids, and 21.89 (95% CI: 14.38, 33.32) for those testing positive for both substances. The interaction effect on fatal crash risk of prescription opioid use and alcohol use was not statistically significant on either additive or multiplicative scale.ConclusionsPrescription opioid use is associated with a significantly increased risk of fatal crash involvement independently of alcohol use. Concurrent use of prescription opioids and alcohol is associated with a 21-fold increased risk of fatal crash involvement.

Navigating Intersections

Older experienced drivers are at a greater risk of fatal crash involvement at intersections than middle-aged experienced drivers. The present cross-sectional study asked older and middle-aged drivers to maneuver various types of intersections (left turn at a 4-way intersection, right turn at a T-intersection and straight through an intersection) in a driving simulator and measured their frequency of glances towards latent and materializing hazards. Results replicate and extend the original findings by Romoser and Fisher (2009). First, the older drivers executed a smaller proportion of primary glances and secondary glances towards target zones where a latent or materializing hazard occurs than middle-aged experienced drivers. Second, older drivers who executed fewer glances toward the hazard were more likely to crash while navigating intersections. These findings provide further evidence for age-related differences in visual scanning for information critical to road safety at intersections. From a practical standpoint, practitioners can utilize better remedial measures in lieu of these age-specific shortcomings.

Effect of Passenger Presence on Older Drivers’ Risk of Fatal Crash Involvement

Objective: To determine the association between passenger presence and risk of fatal crash involvement in relation to driver and passenger age and gender, focusing especially on drivers ages 65 and older. Methods: Data on US fatal crashes were obtained for 2002–2009. Using the quasi-induced exposure methodology, logistic regression analysis was used to predict the odds of fatal crash involvement as a function of driver age and gender as well as passenger age and gender. Results: Overall, risk of fatal crash involvement with passengers was 43 percent lower for drivers ages 65–74 and 38 percent lower for drivers 75 and older. Older drivers’ risk of fatal crash involvement was lower with almost all combinations of passenger age and gender; there was no reduction in risk with passengers ages 75 and older. Effects were stronger at nonintersection locations than at intersection locations. Conclusion: Older drivers’ crash risk is lower with almost every combination of passenger age group and gender. It is unclear whether the presence of passengers lowers older driver crash risk or whether safer drivers tend to ride with passengers.

Update: Repeat DWI Offenders Involvement in Fatal Crashes in 2010

Objective: This analysis is an update of a Traffic Tech published by the National Highway Traffic Safety Administration (NHTSA) in March 1992. Drivers with prior driving-while-intoxicated (DWI) convictions are overrepresented in fatal crashes and the relative risk of fatal crash involvement is greater for these repeat DWI offenders. Methods: Although it is estimated that 2.1 percent of licensed drivers had a prior arrest for DWI within the past 3 years in 2010, 8.0 percent of intoxicated drivers (blood alcohol concentration [BAC] ≥ 0.08 g/dL) involved in fatal crashes had at least one prior DWI conviction in the past 3 years during that same year. Results: Drivers with prior DWI convictions are overrepresented in fatal crashes by a factor of 1.62 or are 62 percent more likely to be in a fatal crash. Similarly, drivers with prior DWI convictions are also overrepresented as drinking drivers in fatal crashes: those with low BACs (0.01–0.07) by a factor of 2.38 and those with high BACs (0.08+) by a factor of 3.81. Conclusion: Though repeat DWI offenders are at a substantially higher risk of fatal crash involvement, the vast majority of intoxicated drivers in fatal crashes do not have a DWI conviction in the past 3 years (11 out of 12) according to the Fatality Analysis Reporting System records for the year 2010.

Drug use and fatal motor vehicle crashes: A case-control study

Drugged driving is a serious safety concern, but its role in motor vehicle crashes has not been adequately studied. Using a case-control design, the authors assessed the association between drug use and fatal crash risk. Cases (n=737) were drivers who were involved in fatal motor vehicle crashes in the continental United States during specific time periods in 2007, and controls (n=7719) were participants of the 2007 National Roadside Survey of Alcohol and Drug Use by Drivers. Overall, 31.9% of the cases and 13.7% of the controls tested positive for at least one non-alcohol drug. The estimated odds ratios of fatal crash involvement associated with specific drug categories were 1.83 [95% confidence interval (CI): 1.39, 2.39] for marijuana, 3.03 (95% CI: 2.00, 4.48) for narcotics, 3.57 (95% CI: 2.63, 4.76) for stimulants, and 4.83 (95% CI: 3.18, 7.21) for depressants. Drivers who tested positive for both alcohol and drugs were at substantially heightened risk relative to those using neither alcohol nor drugs (Odds Ratio=23.24; 95% CI: 17.79, 30.28). These results indicate that drug use is associated with a significantly increased risk of fatal crash involvement, particularly when used in combination with alcohol.

The effects of studded tires on fatal crashes with passenger cars and the benefits of electronic stability control (ESC) in Swedish winter driving

This study set out to examine the effects of studded tires on fatal crashes on roads covered with ice or snow in Sweden and also to investigate the extra benefits of electronic stability control (ESC) during the winter months. Two different studies are presented in this paper. Both studies used an induced exposure approach. In the main study, 369 in-depth studies of fatal crashes with passenger cars were analyzed to determine whether loss-of-control (LOC) had been a major component or not. Only crashes involving cars without ESC and equipped with approved studded or non-studded winter tires were analyzed. The additional study used police-reported crashes that occurred during the winter seasons 2003–2010, involving passenger cars with and without ESC. While police records in Sweden do not include any tire information, it was assumed that most cars involved in crashes during the winter period would be equipped with studded tires.Findings in the main study showed that in 64% of the fatal crashes on roads covered with ice or snow LOC had been a major component. Furthermore, in 82% of LOC crashes, the passenger car over-steered prior to collision. Studded tires were found to have a statistically significant effect of 42% in terms of fatal crash reduction on roads covered with ice or snow, compared to non-studded winter tires. The effect on dry or wet roads in the winter was negative, although statistically non-significant. In the additional study, it was found that ESC further reduced crashes with injuries by 29%. The benefits on severe and fatal crashes were slightly greater (32%), although the lower 95% confidence limit was lower.Although studded tires were shown to reduce the risk of fatal crash involvement, compared to non-studded winter tires, the proportion of LOC and over-steering among cars with studded tires was large (59% and 49%, respectively). It was therefore concluded that studded tires do not prevent all LOC crashes, while ESC has benefits in those crashes since this technology mostly addresses over-steering. This is also supported by the fact that the share of LOC fatal crashes is considerably lower for ESC-equipped cars.This study recommends that non-ESC cars should be fitted with studded tires if they are to be driven on roads covered by ice or snow. If the proportion of studded tires is to be decreased on Swedish roads to reduce the about of hazardous particulates especially in built up areas, from a road safety point of view it is recommended that this should be done in phase with the implementation of ESC on all passenger cars.

Using the U.S. National Household Travel Survey to estimate the impact of passenger characteristics on young drivers’ relative risk of fatal crash involvement

Motor vehicle crashes are the main cause of morbidity and mortality in teenagers and young adults in the United States. Driving exposure and passenger presence, which can both vary by driver and passenger characteristics, are known to influence crash risk. Some studies have accounted for driving exposure in calculating young driver fatal crash risk in the presence of passengers, but none have estimated crash risk by driver sex and passenger age and sex. One possible reason for this gap is that data collection on driving exposure often precludes appropriate analyses. The purpose of this study was to examine, per 10 million vehicle trips (VT) and vehicle-miles traveled (VMT), the relative risk of fatal crash involvement in 15–20-year-old male and female drivers as a function of their passenger's age and sex, using solo driving as the referent. The Fatality Analysis Reporting System provided fatal motor vehicle crash data from 1999 to 2003 and the 2001 National Household Travel Survey (NHTS) provided VT and VMT. The NHTS collects driving exposure for both household and non-household members (e.g., friends, colleagues), but demographic characteristics only on household members. Missing age and sex of non-household passengers were imputed with hot deck using information from household passengers’ trips with non-household drivers, thereby enabling the calculation of crash rate and relative risk estimates based upon driver and passenger characteristics. Using this approach, the highest risk was found for young male drivers with 16–20-year-old passengers (relative risk [RR] per 10 million VT = 7.99; 95% confidence interval [CI], 7.34–8.69; RR per 10 million VMT = 9.94; 95% CI, 9.13–10.81). Relative risk was also high for 21–34-year-old passengers, again particularly when both drivers and passengers were male. These effects warrant further investigation and underscore the importance of considering driving exposure by passenger characteristics in understanding crash risk. Additionally, as all imputation techniques are imperfect, a more accurate estimation of U.S. fatal crash risk per distance driven would require national surveys to collect data on non-household passenger characteristics.

Alcohol-related relative risk of driver fatalities and driver involvement in fatal crashes in relation to driver age and gender: an update using 1996 data.

To re-examine and refine estimates for alcohol-related relative risk of driver involvement in fatal crashes by age and gender as a function of blood alcohol concentration (BAC) using recent data. Logistic regression was used to estimate age/gender specific relative risk of fatal crash involvement as a function of the BAC for drivers involved in a fatal crash and for drivers fatally injured in a crash, by combining crash data from the Fatality Analysis Reporting System with exposure data from the 1996 National Roadside Survey of Drivers. In general, the relative risk of involvement in a fatal vehicle crash increased steadily with increasing driver BAC in every age/gender group among both fatally injured and surviving drivers. Among 16-20 year old male drivers, a BAC increase of 0.02% was estimated to more than double the relative risk of fatal single-vehicle crash injury. At the midpoint of the 0.08% - 0.10% BAC range, the relative risk of a fatal single-vehicle crash injury varied between 11.4 (drivers 35 and older) and 51.9 (male drivers, 16-20). With only very few exceptions, older drivers had lower risk of being fatally injured in a single-vehicle crash than younger drivers, as did women compared with men in the same age range. When comparable, results largely confirmed existing prior estimates. This is the first study that systematically estimated relative risk for drink-drivers with BACs between 0.08% and 0.10% (these relative risk estimates apply to BAC range midpoints at 0.09%.) The results clearly show that drivers with a BAC under 0.10% pose highly elevated risk both to themselves and to other road users. 2000)

The effect of teenage passengers on the fatal crash risk of teenage drivers

Fatal crash-involved drivers of passenger vehicles were identified in the Fatality Analysis Reporting System for the period 1990 through 1995. Each driver was categorized as being alone in the vehicle at the time of the crash or with one or more passengers. Drivers at fault or responsible for crash occurrence were defined as all drivers involved in a single-vehicle crash, or drivers in multiple-vehicle crashes who were coded in the Fatality Analysis Reporting System as committing one or more driver errors. The results indicated that passenger presence was associated with proportionately more at-fault fatal crashes for drivers aged 24 and younger, were a neutral factor for drivers aged 25–29, and were associated with fewer at-fault involvements for drivers aged 30 and older. Relative risk of fatal crash involvement was particularly high for teenage drivers traveling, day or night, with two or more teenage passengers. Additional research is needed to determine how the added risk associated with teenage passengers riding with teenage drivers can be reduced or eliminated.

Fatal crash risk for older drivers at intersections

Risk of fatal crash involvement was calculated for older drivers relative to drivers aged 40–49 in the United States during the years 1994–1995. The results indicated that drivers ages 65–69 were 2.26 times more at risk for multiple-vehicle involvements at intersections compared with 1.29 times more at risk in all other situations. The comparable figures for drivers aged 85 and older were 10.62 for multiple-vehicle involvements at intersections compared with 3.74 for all other situations. The relative crash risk was particularly high for older drivers at uncontrolled and stop sign-controlled locations; when traveling straight or when just starting to enter the intersection; and when the specific behavioral error in the crash was failure to yield. Countermeasures will likely involve reducing or simplifying the need to detect and evaluate moving traffic coming from the left and right when at intersections. This can be accomplished by traffic signals with protected left turns, four-way stop signs, and one-way streets. Whereas such devices involve significant cost in terms of dollars and travel delay, their cost-effectiveness may have to be revisited as the United States population continues to age.

Older drivers: Their night fatal crash involvement and risk

The 1983 Fatal Accident Reporting System (FARS) data and the Nationwide Personal Transportation Study (NPTS) exposure data were used to describe the major problems in night driving that involved older drivers, aged 65 or more, in fatal crashes and to assess their risk. One of the major findings was that the rate of involvement in fatal crashes in darkness of older drivers was much less than for drivers under the age of 25, but greater overall than for drivers aged 25–64. The rate for older females was much less than for older males. Although the overall fatal crash involvement of older drivers is not a serious cause for alarm at this time, the performance of older males does indicate a substantial increase in risk of fatal crash involvement in darkness. These trends can be expected to become more noticeable over the years as a greater proportion of the population in the United States exceeds the age of 65. The older driver crash involvement at night seems to be particularly troublesome for males in multivehicle crashes where they are struck in the side or rear by another vehicle, and single-vehicle crashes where they run off the road on a straight section. Some suggested improvements of the overall night driving environment are discussed.