Driving-while-intoxicated history as a risk marker for general aviation pilots

The Federal Aviation Administration conducts background checking for driving-while-intoxicated (DWI) convictions on all pilots. This study examined the association between DWI history and crash risk in a cohort of 335,672 general aviation pilots. These pilots were followed up from 1994 to 2000 through the aviation crash surveillance system of the National Transportation Safety Board. At baseline, 3.4% of the pilots had a DWI history. DWI history was associated with a 43% increased risk of crash involvement (adjusted relative risk: 1.43; 95% confidence interval: 1.15-1.77). The population-attributable risk fraction for DWI history was estimated as 1.4%. In addition to DWI history, male gender, older age, and inexperience were associated with significantly increased risk of crash involvement. The results of this study support DWI history as a valid risk marker for general aviation pilots. The safety benefit of background checking for DWI history needs to be further evaluated.     

DWI enforcement programs: why are they not more effective?

Enforcement-oriented countermeasure programs to prevent alcohol-related fatal crashes in the United States have not been more effective because they have been based on a number of misconceptions. It is widely believed that (a) 50% of all traffic deaths involve alcohol, (b) alcohol-related fatal crashes are part of a continuum beginning with the minor fender bender, (c) one-third of all fatal crashes are caused by problem drinkers, (d) all problem drinkers, heavy drinkers in general and youth who drink are high-risk drivers and (e), that those arrested for DWI are of the same population as those involved in alcohol-related fatal crashes. It is further believed that mass arrests for DWI would reduce the number of alcohol-related fatal crashes.A review of the literature reveals that the proportion of all fatal crashes involving alcohol in some causal fashion is closer to 30% than to 50%, that relatively few alcoholics are high-risk drivers and that it is not alcohol alone that leads to crash involvement but alcohol in combination with such characteristics or conditions as alienation, hostility, aggression, and/or transient traumatic experiences.Mass arrests for DWI have not been effective in preventing alcohol-related deaths. The frequency of impaired driving episodes is believed to be of such magnitude and the relative likelihood of involvement in an alcohol-related fatal crash is so low that current DWI enforcement programs are regarded as inefficient means to prevent alcohol-related deaths. Recommendations to define the problem more clearly are presented.It is concluded that, if fatal crashes are the problem of concern (as opposed to the use of alcohol), the focus of research must be turned from drinking (per se) to the behavior, characteristics or conditions that precede or accompany fatal crashes, only some of which are triggered or exacerbated by alcohol. This approach would not only focus attention on the estimated 30% of all fatal crashes that involve alcohol, but on the other 70% as well.     

Costs of alcohol-related crashes: New Zealand estimates and suggested measures for use internationally

This paper presents policy-oriented measures of alcohol-related crash incidence and costs in New Zealand (N.Z.). Costs of crashes, where alcohol probably was a contributing factor were computed from official crash costs and police-reported crash/injury counts adjusted for under-reporting of crashes and of alcohol involvement. Alcohol-related crashes cost an estimated $1.2 billion in N.Z. in 1996. They equate to an estimated $0.75 per drink consumed, $17.80 per km driven above the legal limit of 0.08, and $1100 per heavy drinker. People other than the drinkers, who caused the crashes, paid half the costs. An estimated one in 90 drunk-driving trips resulted in a crash (and often a drunk driving conviction) while one in 375 crash-free drunk driving trips also resulted in a drunk-driving conviction. Ten measures of alcohol-related crash incidence and costs are recommended for international use. They include number of alcohol-related deaths and injuries; innocent victims and children harmed in crashes caused by drinkers; annual costs and costs paid by people other than the drinker who caused the crash; crash costs per drink consumed, per heavy drinker, per kilometer driven drunk versus sober; probabilities of crash and of drunk-driving conviction.     

US commercial air tour crashes, 2000–2011: Burden,fatal risk factors,and FIA Score validation

Introduction

This study provides new public health data concerning the US commercial air tour industry. Risk factors for fatality in air tour crashes were analyzed to determine the value of the FIA Score in predicting fatal outcomes.

Methods

Using the Federal Aviation Administration's (FAA) General Aviation and Air Taxi Survey and National Transportation Safety Board data, the incidence of commercial air tour crashes from 2000 through 2010 was calculated. Fatality risk factors for crashes occurring from 2000 through 2011 were analyzed using regression methods. The FIA Score, Li and Baker's fatality risk index, was validated using receiver operating characteristic (ROC) curves.

Results

The industry-wide commercial air tour crash rate was 2.7 per 100,000 flight hours. The incidence rates of Part 91 and 135 commercial air tour crashes were 3.4 and 2.3 per 100,000 flight hours, respectively (relative risk [RR] 1.5, 95% confidence interval [CI] 1.1–2.1, P = 0.015). Of the 152 air tour crashes that occurred from 2000 through 2011, 30 (20%) involved at least one fatality and, on average, 3.5 people died per fatal crash. Fatalities were associated with three major risk factors: fire (adjusted odds ratio [AOR] 5.1, 95% CI 1.5–16.7, P = 0.008), instrument meteorological conditions (AOR 5.4, 95% CI 1.1–26.4, P = 0.038), and off-airport location (AOR 7.2, 95% CI 1.6–33.2, P = 0.011). The area under the FIA Score's ROC curve was 0.79 (95% CI 0.71–0.88).

Discussion

Commercial air tour crash rates were high relative to similar commercial aviation operations. Disparities between Part 91 and 135 air tour crash rates reflect regulatory disparities that require FAA action. The FIA Score appeared to be a valid measurement of fatal risk in air tour crashes. The FIA should prioritize interventions that address the three major risk factors identified by this study.     

A review of risk factors and patterns of motorcycle injuries

Per vehicle mile traveled, motorcycle riders have a 34-fold higher risk of death in a crash than people driving other types of motor vehicles. While lower-extremity injuries most commonly occur in all motorcycle crashes, head injuries are most frequent in fatal crashes. Helmets and helmet use laws have been shown to be effective in reducing head injuries and deaths from motorcycle crashes. Alcohol is the major contributing factor to fatal crashes. Enforcement of legal limits on the blood alcohol concentration is effective in reducing motorcycle deaths, while some alcohol-related interventions such as a minimal legal drinking age, increased alcohol excise taxes, and responsible beverage service specifically for motorcycle riders have not been examined. Other modifiable protective or risk factors comprise inexperience and driver training, conspicuity and daytime headlight laws, motorcycle licensure and ownership, riding speed, and risk-taking behaviors. Features of motorcycle use and potentially effective prevention programs for motorcycle crash injuries in developing countries are discussed. Finally, recommendations for future motorcycle-injury research are made.     

Consideration of driver home county prohibition and alcohol-related vehicle crashes

This study examines the characteristics of alcohol-related crashes in wet versus dry counties in the state of Kentucky, USA and incorporates the location of driver residences through use of geographic information system (GIS) analysis. Between 1991 and 1997, 39344 alcohol-related crashes by Kentucky residents on Kentucky State roads were reported. The location of the crash and the home ZIP code from the driver's address were used to consider distance from home in the GIS. Analysis of the crash data revealed that a similar proportion of crashes in wet and dry counties are alcohol-related but that a higher proportion of dry counties residents are involved in an alcohol-related crash. However, when the distance from home variable is considered, several results suggest that dry county residents may be driving further when consuming alcohol. In part due to the rural nature of dry counties, drivers from dry counties have both alcohol-related and non-alcohol related crashes farther from their homes than residents from wet counties. Alcohol-related crashes by dry county residents in wet counties are the greatest average distance from home while crashes by wet county residents in wet counties are the smallest average distance. Drivers from dry counties over 21 years of age have alcohol-related crashes significantly farther from home than those under 21 who would not legally be admitted to drinking establishments in the wet counties. Furthermore, residents from dry counties that do not border wet counties have alcohol-related crashes on average farther from home than the border county residents. These last three results provide circumstantial evidence that some dry county drivers may be driving to wet counties to consume alcohol thus increasing impaired driving exposure. In conclusion, by considering crash location and driver residence, these findings indicate that county-level prohibition is not necessarily effective in improving highway safety.     

Trends in fatal crashes involving female drivers, 1975-1998

Since the mid-1980s there has been concern about the growing number of female drivers in the US involved in fatal motor vehicle crashes, and similar trends have been noted in other parts of the world. The present study examined whether this trend has continued into the 1990s and the reasons for it. Fatal crash data were obtained from the Fatality Analysis Reporting System (FARS), mileage data from the National Personal Transportation Survey, and licensure data from the Federal Highway Administration. Many more women were licensed to drive in 1998 than in 1975, and on average they drove more miles. When changes in total annual mileage were taken into account, per-mile crash rates decreased similarly for men and women (about 40%). An examination of the characteristics of their fatal crashes revealed that male and female drivers have seen similar reductions in single-vehicle, nighttime, and alcohol-related crashes. However, men continue to be involved more often in these types of crashes.     

The relationship between blood alcohol concentration and crash responsibility for fatally injured drivers.

Data for 595 fatally injured drivers in Texas were analyzed using logistic regression to determine the probability of crash responsibility as a function of blood alcohol concentration (BAC). Three independent panelists rated crash responsibility on a three-point scale, based on information contained in traffic accident reports. High inter-rater reliability was noted. Panel members were in agreement 98% of the time, unanimously assigning full responsibility in 61% of the cases and no responsibility in 31% of the cases. In addition to BAC, time of day and day of week were considered as variables in the regression model. A highly significant (P less than .01) relationship was found between BAC and the probability of crash responsibility. Furthermore, results of the analysis support previous studies that noted a high rate of responsibility among fatally injured drivers, in general, even those with negative BAC test results. Such findings are of importance in evaluating driver impairment at various BACs and for determining other factors that interact with alcohol in driver fatality crashes.     

The outcome from legalizing Sunday packaged alcohol sales on traffic accidents in New Mexico

We attempt to disentangle the effect on alcohol-related accidents and fatal crashes when New Mexico lifted its ban on Sunday packaged alcohol sales on July 1, 1995. Using crash incidents between January 1990 and December 2005, from data maintained by the Division of Government Research in New Mexico, we estimate a negative binomial model that controls for unobservable factors affecting overall accidents. One of these factors is an increase in New Mexico's speed limits in 1996. We find no statistically significant increase in total alcohol-related accidents or alcohol-related fatal crashes on Sundays after the repeal of the ban.     

The impact of alcohol and road traffic policies on crash rates in Botswana, 2004–2011: A time-series analysis

In Botswana, increased development and motorization have brought increased road traffic-related death rates. Between 1981 and 2001, the road traffic-related death rate in Botswana more than tripled. The country has taken several steps over the last several years to address the growing burden of road traffic crashes and particularly to address the burden of alcohol-related crashes. This study examines the impact of the implementation of alcohol and road safety-related policies on crash rates, including overall crash rates, fatal crash rates, and single-vehicle nighttime fatal (SVNF) crash rates, in Botswana from 2004 to 2011. The overall crash rate declined significantly in June 2009 and June 2010, such that the overall crash rate from June 2010 to December 2011 was 22% lower than the overall crash rate from January 2004 to May 2009. Additionally, there were significant declines in average fatal crash and SVNF crash rates in early 2010. Botswana's recent crash rate reductions occurred during a time when aggressive policies and other activities (e.g., education, enforcement) were implemented to reduce alcohol consumption and improve road safety. While it is unclear which of the policies or activities contributed to these declines and to what extent, these reductions are likely the result of several, combined efforts.     

Alcohol use, driving records, and crash culpability among injured motorcycle drivers

Alcohol use, driving records, crash culpability, and crash conviction rates for 165 injured motorcycle drivers (MTCDs) were studied. Of the 165 MTCDs, 53.3% tested positive for alcohol (BAC+). Culpability determinations (n = 150) revealed that 83% of BAC+ and 46% of BAC- MTCDs caused their crashes (p < 0.001). Driving records (n = 145) revealed the following prevalence of one or more convictions for BAC+ and BAC- MTCDs: impaired driving (29% vs. 7%, p < 0.001); speeding (74% vs. 58%, p < 0.05); and reckless driving (68% vs. 44%, p < 0.002). Of the surviving culpable impaired MCTDs (n = 48), 16.7% received crash-related convictions, 12.5% received alcohol-related convictions. The reasons for the low conviction rates are probably multifactoral.     

Associations between driving under the influence of alcohol or drugs,speeding and seatbelt use among fatally injured car drivers in Norway

Since 2005, all fatal road traffic crashes in Norway have been analyzed in-depth by multidisciplinary investigation teams organized by the Norwegian Public Roads Administration (NPRA). During the period 2005–2010, 608 drivers of cars or vans were killed in road traffic crashes. Blood samples were collected from 372 (61%) of the drivers and analyzed for alcohol and a large number of psychoactive drugs at the Norwegian Institute of Public Health (NIPH). After coupling the analytical results with the NPRA crash database, 369 drivers with a fatal outcome were identified and included. Alcohol or drug concentrations in blood above the legal limits were found in 39.8% of the drivers who were investigated for alcohol or drug impairment; 33.9% had blood alcohol concentrations above 0.5 g/L or concentrations of drugs above the equivalent Norwegian legal impairment limits or concentrations of amphetamines above 200 μg/L. Among drivers with a fatal outcome who had been impaired by alcohol or drugs, 64.6% were unbelted and 71.7% were speeding when the crash occurred; whereas 24.2% and 33.2% of the sober drivers were unbelted or speeding, respectively. Statistically significant associations were found between impairment by alcohol or amphetamines and driving unbelted or speeding. Excessive speeding is one of the main reasons for road traffic crashes and together with being unbelted the main reasons for a fatal outcome. This behavior might in many cases be due to increased risk-taking or negligence of safety measures as a result of alcohol or drug use.     

Helmet use, patterns of injury, medical outcome, and costs among motorcycle drivers in Maryland.

A comprehensive study was conducted of all motorcycle traffic crashes occurring in Maryland during a one-year period. All available medical and cost data were linked with police crash reports. During the study period, 1,900 motorcycle drivers were involved in crashes. The data indicated that (i) helmet usage was 35% overall, 30% among fatally injured drivers, and only 16% among drivers with a history of drug/alcohol conviction, (ii) unhelmeted drivers seen at an emergency department were almost twice as likely to have sustained head injury (40%) as were helmeted drivers (21%) (the corresponding percentages for hospitalized drivers were 55% and 38%), and (iii) acute care cost for unhelmeted drivers was three times ($30,365) that of helmeted drivers.     

Segment characteristics and severity of head-on crashes on two-lane rural highways in Maine

More than two out of three of all fatal crashes in Maine occur on rural, two-lane collector or arterial roads. Head-on crashes on these roads account for less than 5% of the crashes, but they are responsible for almost half of all fatalities. Data analyzed in this study was provided by Maine Department of Transportation and covers all head-on crashes for 2000-2002 during which period there were 3,136 head-on crashes reported. Out of these, 127 were fatal crashes and 235 produced incapacitating but not fatal injuries. These two categories made up over 75% of the crash cost. A clear majority of head-on crashes on two-lane, rural roads in Maine were caused by drivers making errors or misjudging situations. Illegal/unsafe speed was a factor in 32% of the crashes while driver inattention/distraction was a primary factor in 28%. Fatigue was responsible for around one in 40 crashes and one in 12 fatal crashes. Alcohol or drugs was a factor in one in 12 crashes and one in nine fatal head-on crashes. Less than 8% of fatalities involved someone overtaking another vehicle, and only around 14% involved a driver intentionally crossing the centerline. Two in three fatal head-on crashes occurred on straight segments and 67% of these happened on dry pavement. There is a clear trend towards higher speed limits leading to a higher percentage of crashes becoming fatal or having incapacitating injuries. There is also a clear trend - if one keeps speeds constant and AADT within a certain range - that wider shoulders give higher crash severities. Also, for higher-speed roads, more travel lanes (than two) increase crash severity. In summary, there seems to be two major reasons why people get across the centerline and have head-on collisions: (a) people are going too fast for the roadway conditions; or (b) people are inattentive and get across the centerline more or less without noticing it. The latter category of crashes could probably be reduced if centerline rumble-strips were installed. More or less all head-on collisions could be eliminated if median barriers were installed. In-vehicle technology could also be used to significantly reduce the incidence of lane departures. Furthermore, today's speed limits should be better enforced since a high percentage of serious crashes involve illegal speeding. This should be combined with lowered speed limits for targeted high-crash segments.     

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.     

Propensity scores-potential outcomes framework to incorporate severity probabilities in the Highway Safety Manual crash prediction algorithm

Accurate estimation of the expected number of crashes at different severity levels for entities with and without countermeasures plays a vital role in selecting countermeasures in the framework of the safety management process. The current practice is to use the American Association of State Highway and Transportation Officials’ Highway Safety Manual crash prediction algorithms, which combine safety performance functions and crash modification factors, to estimate the effects of safety countermeasures on different highway and street facility types. Many of these crash prediction algorithms are based solely on crash frequency, or assume that severity outcomes are unchanged when planning for, or implementing, safety countermeasures. Failing to account for the uncertainty associated with crash severity outcomes, and assuming crash severity distributions remain unchanged in safety performance evaluations, limits the utility of the Highway Safety Manual crash prediction algorithms in assessing the effect of safety countermeasures on crash severity. This study demonstrates the application of a propensity scores-potential outcomes framework to estimate the probability distribution for the occurrence of different crash severity levels by accounting for the uncertainties associated with them. The probability of fatal and severe injury crash occurrence at lighted and unlighted intersections is estimated in this paper using data from Minnesota. The results show that the expected probability of occurrence of fatal and severe injury crashes at a lighted intersection was 1 in 35 crashes and the estimated risk ratio indicates that the respective probabilities at an unlighted intersection was 1.14 times higher compared to lighted intersections. The results from the potential outcomes-propensity scores framework are compared to results obtained from traditional binary logit models, without application of propensity scores matching. Traditional binary logit analysis suggests that the probability of occurrence of severe injury crashes is higher at lighted intersections compared to unlighted intersections, which contradicts the findings obtained from the propensity scores-potential outcomes framework. This finding underscores the importance of having comparable treated and untreated entities in traffic safety countermeasure evaluations.     

Injury typology of fatal motorcycle collisions with roadside barriers in Australia and New Zealand

Motorcyclists contribute significantly to road trauma around the world through the high incidence of serious injuries and fatalities. The role of roadside safety barriers in such trauma is an area of growing concern amongst motorcyclists, road authorities and road safety researchers and advocates. This paper presents a case series analysis of motorcyclists that were fatally injured following a collision with a roadside barrier during the period 2001–2006 in Australia and New Zealand. Injury profiles and severities are detailed, and associations with crash characteristics are investigated. It is shown that the thorax region had the highest incidence of injury and the highest incidence of maximum injury in fatal motorcycle-barrier crashes, followed by the head region. This is in contrast to fatal motorcycle crashes in all single- and multi-vehicle crash modes, where head injury predominates. The injury profiles of motorcyclists that slid into barriers and those that collided with barriers in the upright posture were similar. However, those that slid in were more likely to receive thorax and pelvis injuries.