Single-vehicle Nighttime Crashes Research Articles

Alcohol Compliance Checks and Underage Alcohol-Involved Crashes: Evaluation of a Statewide Enforcement Program in South Carolina from 2006 to 2016.

This research evaluated the South Carolina Alcohol Enforcement Team impact for reducing retail alcohol access to underage persons to decrease drinking and driving crashes among that population. The natural research experiment used interrupted time-series (ITS) analyses of drinking and driving crashes involving under 21-year-old drivers from July 2006 through December 2016 (126-month period=4,782 Driving Under Influence [DUI] crashes for under 21-year-old drivers, µ=38 crashes per month). Additional data analyzed included the monthly total number of retail compliance checks (total during 126-month period=64,954 compliance checks completed, µ=515.5 checks per month), the average percentage of underage alcohol purchases (total completed during 126-month period=8,814 purchases, µ=70 purchases per month), and a calculated measure of the percent of the population under 21years old exposed to compliance checks each month. We used drinking and driving crashes for 21-year-old and over drivers as a control time series (total number over a 126-month period=52,180 DUI crashes for 21 and older drivers, µ=414.1 crashes per month). The results show a decline in drinking and driving crashes for drivers under 21 when compliance checks increase, and when compliance checks decline, traffic crashes increase. Stable Alcohol Enforcement Team implementation over 78months produced an overall 18 to 29% decline in such crashes. A visual examination of the crash time series demonstrated that under-21-age-driver crashes declined during the first wave of implementation and increased following a lag when enforcement declined, which provided additional empirical support for a South Carolina Alcohol Enforcement Team impact on retail alcohol availability. An ITS analysis of the prestable period compared to the stable period was statistically significant (T=-3.78, p<0.001). A cross-check of these results using single-vehicle nighttime crashes using identical Autoregressive Integrated Moving Average models was also statistically significant (T=-8.18, p<0.001). This longitudinal study provides strong evidence of sustained reductions in alcohol availability to underage youth can subsequently reduce alcohol-related traffic crashes. Reductions found in this study continued over several years, considerably longer than any previous equivalent research has shown.

Effects of a Community-Level Intervention on Alcohol-Related Motor Vehicle Crashes in California Cities: A Randomized Trial

This trial assesses the effects of a community-level alcohol prevention intervention in California on alcohol-related motor vehicle crashes. The study is a group RCT with cities as the unit of assignment to condition and as the unit of analysis. A total of 24 California cities with populations between 50,000 and 450,000 were chosen at random and roughly matched into pairs before randomly assigning 12 each to the intervention and control conditions. The intervention, aimed at reducing excessive drinking among adolescents and young adults, included driving under the influence sobriety checkpoints, saturation patrols, and undercover operations to reduce service of alcohol to intoxicated patrons in bars, all including high visibility so the public would be aware of them. A measure of overall intervention intensity or dosage was created. The outcome was a monthly percentage of all motor vehicle crashes that were single vehicle nighttime crashes for drivers aged 15-30 years. Multilevel analyses were conducted to examine intervention effects on alcohol-related crashes among drivers aged 15-30 years. Crash data were obtained in 2018 with data preparation and analysis conducted in 2019. Intent-to-treat analyses indicated a 17% reduction in the percentage of alcohol-involved crashes among drivers aged 15-30 years relative to controls, which translates to about 310 fewer crashes. Dosage was found to have a statistically significant effect on crashes among this age group, although not in the expected direction. Enhanced alcohol enforcement operations involving both community health and law enforcement agencies can help to reduce alcohol-impaired driving and related consequences among young people. Including measures of intervention dosage raises interesting questions about the understanding of the impact of the community intervention. Future studies should continue to further develop implementation strategies that may more effectively and efficiently reduce community alcohol-related harm.

Crash patterns in two Chinese secondary cities, with comparisons to crash patterns in the United States

Objective: Evaluations of drink-driving crash interventions and crash burden in middle-income countries often rely on assumptions supported by data from the United States. We described crashes using pooled survey data across 2 Chinese agricultural cities in the 600,000 population range and then assessed comparability of selected crash characteristics to those in the United States.Methods: We conducted household interviews on drinking and related harms with representative samples of 1,500 people aged 18 and over in both Jiangshan and Lanxi, China. Near the end of the survey, 2,962 people responded to questions about motor vehicle crashes during the past year. We report survey data weighted to match the population demographically.Results: Across the 2 cities, 28% of adults were licensed drivers and 24% drove a motorized vehicle. Fifty-three respondents (unweighted) reported that they personally were involved in at least one crash in the past year. Among these, 32% (weighted) were driving a car, truck, or bus; 7.5% were driving a motorcycle; 9.5% were pedalcyclists; 17% were pedestrians; and 34% were passengers. Of the crashes, 42% involved just one motorized vehicle. Most crashes (62%) occurred in broad daylight, followed by at dawn or dusk (19%) and at night (19%). Only 4% were single-vehicle nighttime crashes. Someone was injured or killed in 22% of crashes. Respondents thought it likely that at least one driver was drinking alcohol in 21% of the crashes and thought it unlikely in 51%; the remaining 28% were unsure whether anyone was drinking or refused this question. Alcohol involvement was similar in injury and no-injury crashes. Respondents thought a driver had been drinking in 24% of daytime crashes, 34% of crashes at dawn or dusk, and 36% of nighttime crashes. All 3 crashes involving an alcohol-involved pedestrian or pedalcyclist also included an alcohol-involved driver. Respondents said that 40% of the crashes were reported to the police and 40% were not reported; the remaining 20% of respondents did not know whether anyone reported their crash. Among crashes where reporting status was known, all crashes with injuries were reported.Conclusions: Compared to published data, crash rates are similar among licensed drivers in the United States and these Chinese cities. The percentage of crashes that involved injury did not differ significantly between the 2 countries. Injury crashes were well reported in both. Crashes involving property damage only were significantly less likely to be reported to the police in the Chinese cities. Alcohol involvement rates in crashes were similar. Although our crash sample was small, some crash parameters appear to be transferable between these 2 countries.

Space-Time Analyses of Alcohol Outlets and Related Motor Vehicle Crashes: Associations at City and Census Block-Group Levels.

Past research has linked alcohol outlet densities to drinking, drunken driving, and alcohol-related motor vehicle crashes (MVCs). Because impaired drivers travel some distances from drinking places to crash locations, spatial relationships between outlets and crashes are complex. We investigate these relationships at 3 geographic levels: census block groups (CBGs), adjacent (nearby) areas, and whole cities. We examined risks of all injury MVCs as well as "had been drinking" (HBD) and single-vehicle-nighttime (SVN) subgroups using data from the Statewide Integrated Traffic Records System across CBGs among 50 California cities from 2001 to 2008. Relationships between outlet densities at the city level, within CBGs, and in adjacent CBGs and crashes were examined using Bayesian Poisson space-time analyses controlling for population size income and other demographics (all as covariates). All injury MVCs were positively related to adjacent CBG population size (relative rate [RR]=1.008, 95% credible interval (CI)=1.004, 1.012), and outlet densities at CBG (RR=1.027, CI=1.020, 1.035), nearby area (RR=1.084, CI=1.060, 1.106) and city levels (RR=1.227, CI=1.147, 1.315), and proportion of bars or pubs at the city level (RR=2.257, CI=1.187, 4.125). HBD and SVN crashes were comparatively less frequent in high outlet density CBG (RR=0.993, CI=0.987, 0.999; RR=0.963, CI=0.951, 0.975) and adjacent areas (RR=0.979, CI=0.962, 0.996; RR=0.909, CI=0.883, 0.936), but positively associated with city-level proportions of bars (RR=3.373, CI=0.736, 15.644; RR=10.322, CI=1.704, 81.215). Overall, a 10% increase in alloutlets was related to 2.8% more injury crashes (CI=2.3, 3.3) and 2.5% more HBDs (CI=1.7, 3.3). A10% increase in bars was related to 1.4% more crashes, 4.3% more HBDs, and 10.3% more SVNs. Population size and densities of bars or pubs were found to be associated with crash rates, with population effects appearing across cities and outlet effects appearing within dense downtown areas. Summary estimates of outlet and population impacts on MVCs must consider varying contributions at multiple spatial scales.

Alcohol and non-alcohol-related motor vehicle crashes in Perth, Australia: Do alcohol outlets make a difference?

This study examined the effects of distance from alcohol outlets to motor vehicle crashes across the Perth metropolitan area. A retrospective population-based study was undertaken using measures of alcohol- and non-alcohol-related crashes, and their proximity to alcohol outlets, using a geographic information system. Two logistic regression models were developed with the following outcomes: i) crashes including drivers with BAC ≥ 0.05%, and ii) weekend single vehicle night-time crashes, a surrogate measure of alcohol-related crashes. The surrogate measures of non-alcohol-related crashes for these models were all day-time and single vehicle day-time crashes respectively. The major predictors of alcohol-related crashes were number of on-premise outlets and bottleshops in buffer zones up to 2 km, 2 km–5 km, 5 km–10 km and 10 km-20 km from crashes. The distance from the central business district (CBD) and sociodemographic factors were controlled for. The study included 341,467 crashes that occurred between 2005 and 2015. The highest crash incidence rates occurred in the CBD. The statistical models indicated that crashes with a higher number of on-premise outlets in adjacent buffer zones were more likely to be alcohol-related than non-alcohol-related crashes. Crashes with a higher number of on-premise outlets less than 2 km, 2 km–5 km, 5 km–10 km, and 10 km–20 km from the crashes were significantly more likely to be weekend single vehicle night-time crashes than day-time crashes (OR = 1.014; 95% CI:1.002-1.027, OR = 1.022; 95% CI:1.014-1.029, OR = 1.019; 95% CI:1.014-1.024, and OR = 1.017; 95% CI:1.014-1.020 respectively). There was some evidence that crashes with lower number of bottleshops in adjacent buffer zones were more likely to be alcohol-related crashes, although this was not consistent across both models and all buffer zones. When other predictors were controlled for, alcohol-related crashes were more likely to occur further from the CBD, than in the CBD. Recommendations about the timing and location of roadside alcohol testing are made.

Factors Predicting Local Effectiveness of Impaired Driving Laws, British Columbia, Canada.

In 2010, British Columbia introduced laws allowing police to suspend licenses and impound vehicles of drinking drivers based on roadside breath alcohol analysis results. This study examines regional variation in the effectiveness of the new laws and identifies local factors that may have modified the laws' effectiveness. First, we used an interrupted time series design with a negative binomial mixed model to study the change in rate of single-vehicle nighttime crashes (SVNCs; a proxy for alcohol-related crashes) in each of British Columbia's 118 police patrols after the laws were introduced. Next, the role of explanatory factors was studied using patrol-level estimated percent reduction in SVNCs as the response variable in a linear regression model with spatially autocorrelated errors that included explanatory factors as covariates. The average rate of SVNCs across police patrols was 12% lower (95% CI [9.1%, 14.8%]) following the new laws, and all police patrols included in our model had estimated reductions in SVNCs. Reductions in SVNCs were positively associated with the number of alcohol-serving establishments per capita and with socioeconomic status and were negatively associated with baseline rates of traffic citations. The laws were associated with improved road safety across the province but were least effective in more socioeconomically disadvantaged regions. Increased effectiveness in regions with more alcohol-serving establishments may have indicated a specific deterrent effect on drinking drivers who frequent these establishments. The laws were also more effective in regions with lower baseline traffic law enforcement (i.e., lower citation rates), perhaps because media reports about the immediate roadside penalties regime created unease in drinking drivers who previously knew that their risk of punishment for traffic law violations was low.

The Association between Regional Environmental Factors and Road Trauma Rates: A Geospatial Analysis of 10 Years of Road Traffic Crashes in British Columbia, Canada.

BackgroundBritish Columbia, Canada is a geographically large jurisdiction with varied environmental and socio-cultural contexts. This cross-sectional study examined variation in motor vehicle crash rates across 100 police patrols to investigate the association of crashes with key explanatory factors.MethodsEleven crash outcomes (total crashes, injury crashes, fatal crashes, speed related fatal crashes, total fatalities, single-vehicle night-time crashes, rear-end collisions, and collisions involving heavy vehicles, pedestrians, cyclists, or motorcyclists) were identified from police collision reports and insurance claims and mapped to police patrols. Six potential explanatory factors (intensity of traffic law enforcement, speed limits, climate, remoteness, socio-economic factors, and alcohol consumption) were also mapped to police patrols. We then studied the association between crashes and explanatory factors using negative binomial models with crash count per patrol as the response variable and explanatory factors as covariates.ResultsBetween 2003 and 2012 there were 1,434,239 insurance claim collisions, 386,326 police reported crashes, and 3,404 fatal crashes. Across police patrols, there was marked variation in per capita crash rate and in potential explanatory factors. Several factors were associated with crash rates. Percent roads with speed limits ≤ 60 km/hr was positively associated with total crashes, injury crashes, rear end collisions, and collisions involving pedestrians, cyclists, and heavy vehicles; and negatively associated with single vehicle night-time crashes, fatal crashes, fatal speeding crashes, and total fatalities. Higher winter temperature was associated with lower rates of overall collisions, single vehicle night-time collisions, collisions involving heavy vehicles, and total fatalities. Lower socio-economic status was associated with higher rates of injury collisions, pedestrian collisions, fatal speeding collisions, and fatal collisions. Regions with dedicated traffic officers had fewer fatal crashes and fewer fatal speed related crashes but more rear end crashes and more crashes involving cyclists or pedestrians. The number of traffic citations per 1000 drivers was positively associated with total crashes, fatal crashes, total fatalities, fatal speeding crashes, injury crashes, single vehicle night-time crashes, and heavy vehicle crashes. Possible explanations for these associations are discussed.ConclusionsThere is wide variation in per capita rates of motor vehicle crashes across BC police patrols. Some variation is explained by factors such as climate, road type, remoteness, socioeconomic variables, and enforcement intensity. The ability of explanatory factors to predict crash rates would be improved if considered with local traffic volume by all travel modes.

Evaluating the effects of a large increase in off-sale alcohol outlets on motor vehicle crashes: a time-series analysis

This study examined the effects on motor vehicle crashes of a policy change that led to the introduction of a very large number of off-sale alcohol outlets in Lubbock, Texas. Times-series analysis of total crashes and single-vehicle nighttime (SVN) crashes was used to compare the periods before and after the policy change in Lubbock and in a comparison area. The results of the analysis revealed some weak effects on total crashes, but no statistically significant effects were found for SVN crashes. Possible reasons for the essentially null findings of the current study regarding the effects of the policy change on motor vehicle crashes are discussed. These include the fact that there were a small number of off-sale outlets already present in the community and that motor vehicle travel immediately following alcohol consumption is less likely to occur with alcohol purchased from an off-sale outlet compared to an on-sale outlet.

Diverging trends in alcohol consumption and alcohol‐related harm in Victoria

To examine recent trends in alcohol-related harm and risky drinking in Victoria, Australia. The study compiled eight measures of alcohol-related harm from published and unpublished sources, covering data relating to health, crime, alcohol treatment and traffic crashes for the financial years 1999/2000 to 2007/08. In addition, published estimates of short and long-term risky drinking from three-sets of surveys between 2001 and 2007 were examined. Six of the eight harm indicators substantially increased, while only alcohol-related mortality and single-vehicle night-time crashes remained relatively stable. In particular, rates of emergency presentations for intoxication and alcohol-related ambulance attendances increased dramatically. Contrastingly, survey-derived estimates of the rate of risky-drinking among Victorians were stable over the time-period examined. Evidence across the data examined suggests significant increases in alcohol-related harm taking place during a period of relatively stable alcohol consumption levels. This disparity may be accounted for by changing drinking patterns among small, high-risk, subgroups of the population. The sharply increasing rates of alcohol-related harm among Victorians suggest that changes to alcohol policies focusing on improving public health are necessary.

The geography of availability and driving after drinking.

This paper reports on an analysis of geographically based data from four communities conducted to evaluate relationships between measures of the physical availability of alcohol and rates of driving after drinking. From a review of the literature, it was expected that rates of driving after drinking would be directly related to the availability of alcohol at on-premise establishments. Based on theoretical arguments regarding the life activities which underlie drinking and driving it was expected that the effects of availability upon these outcomes would extend significantly beyond the local areas of outlets. Taking into account the geographic variations in environmental characteristics (road network density, traffic flow, population density), and socioeconomic (age, gender, race, marital status, income, employment) and drinking characteristics (rates of abstention, frequency and quantity of use) of resident populations, a spatial analysis of drinking driving and alcohol-related crashes was conducted. The results of the analysis showed that physical availability was unrelated to self-reports of driving after drinking and driving while intoxicated and significantly related to rates of single vehicle night-time crashes. In the latter case, physical availability affected both local and adjacent area rates of crashing.

Female drinking and driving: Recent trends in North Carolina

Data on driver licensing, DWI arrests, crashes, and fatalities in the State of North Carolina from the mid-70s to the mid-80s are analyzed to examine trends in drinking and driving by women. Findings presented are based on rates per licensed driver. Results suggest that more women are driving and are experiencing greater exposure to the hazards of drinking and driving. DWI arrest rates for women increased by 43% while rates for men decreased by 9%. Likewise, the proportion of legally intoxicated drivers among women is increasing. Women account for a growing proportion of alcohol-related (A/R) crashes and their involvement in single vehicle nighttime crashes is increasing. A dramatic decrease was observed in A/R fatalities in the male licensed driving population. This decrease was not paralleled by women. Authors conclude women will make up an increasing proportion of those arrested and convicted for DWI and will have more A/R crashes. Findings have implications for the design and implementation of education, deterrence, enforcement, and rehabilitation programs.

Direct observation of seat belt use in Michigan: April 1986 : A.C. Wagenaar, K.L. Businski, and L. J. Molnar, University of Michigan, Transportation Research Institute, Ann Arbor, MI, May 1986, UMTRI-86-27

Results of a 6-year follow-up of previous research evaluating the effects of Michigan's December 1978 increase in the legal drinking age from 18 to 21 are reported. Earlier research demonstrated the immediate effect of Michigan's raised legal age in reducing motor vehicle crash involvement among young drivers. The current study examined 6 years of post-law traffic crash data, using Box-Jenkins intervention analysis methods to assess the long-term effects of the raised drinking age. Results revealed long-term ef- fects of the law similar to the initial effects identified earlier. Over the 6-year follow-up period, the rate of involvement in injury-producing single-vehicle nighttime crashes among drivers age 18–20 was 16 % lower than the level ex- pected, had the drinking age law not changed. Police-reported drinking driver crash involvement was down 19%. In contrast to many alcohol-im- paired driving countermeasures, the raised legal drinking age appears to have a long-term effect in reducing motor vehicle crash involvement among young drivers.

Preventing highway crashes by raising the legal minimum age for drinking: The Michigan experience 6 years later

Results of a 6-year follow-up of previous research evaluating the effects of Michigan's December 1978 increase in the legal drinking age from 18 to 21 are reported. Earlier research demonstrated the immediate effect of Michigan's raised legal age in reducing motor vehicle crash involvement among young drivers. The current study examined 6 years of post-law traffic crash data, using Box-Jenkins intervention analysis methods to assess the long-term effects of the raised drinking age. Results revealed long-term ef- fects of the law similar to the initial effects identified earlier. Over the 6-year follow-up period, the rate of involvement in injury-producing single-vehicle nighttime crashes among drivers age 18–20 was 16 % lower than the level ex- pected, had the drinking age law not changed. Police-reported drinking driver crash involvement was down 19%. In contrast to many alcohol-im- paired driving countermeasures, the raised legal drinking age appears to have a long-term effect in reducing motor vehicle crash involvement among young drivers.