The impact on alcohol-related collisions of the partial decriminalization of impaired driving in British Columbia, Canada

Examining the impact of legalization on the prevalence of driving after using cannabis: A comparison of rural and non-rural parts of Canada

OBJECTIVE

The purpose of this study was to examine the likelihood of driving after using cannabis, and of being a passenger with someone who is driving after using cannabis, in rural areas and non-rural areas before and after legalization.

METHODS

A multi-wave analysis of Canada's National Cannabis Survey was conducted using logistic regression with interactions to predict the prevalence of driving after using cannabis, and of being a passenger with someone who is driving after using cannabis, in relation to place of residence (rural or non-rural) and in the weeks and months before and after legalization. Three time points were compared: pre-legalization, two months following legalization and 1 year after legalization.

RESULTS

At the national level, there are no significant differences between the predicted estimates of driving after using cannabis for those who live in rural and non-rural areas. However, when examining the impact of legalization, we found a significant increase in driving after using cannabis among rural residents directly following legalization. Furthermore, it was observed that this increase in driving after using cannabis returns to pre-legalization rates one year after legalization. By contrast, in the weeks and months following legalization, driving after using cannabis decreased among those living in non-rural areas, and slowly increased soon thereafter. No significant differences were observed, in either time period or group, in the prevalence of being a passenger with someone who is driving after using cannabis.

CONCLUSIONS

The finding of significantly higher risk of driving after use of cannabis soon after legalization in rural areas suggests a need for more attention to address immediate concerns for public safety. The increased potential for traffic injuries and deaths in other jurisdictions contemplating legalization supports the call for more and better targeted prevention efforts in rural communities that have far too often been overlooked and under-served.

Unveiling the relevance of traffic enforcement cameras on the severity of vehicle-pedestrian collisions in an urban environment with machine learning models

PURPOSE

One of the leading causes of violent fatalities around the world is road traffic collisions, and pedestrians are among the most vulnerable road users with respect to such incidents. Since walking is highly promoted in urban areas to alleviate motor-vehicle externalities, it is paramount to understand the causes associated with vehicle-pedestrian collisions and their severity to provide safe environments. Although traffic enforcement cameras can address vehicle-vehicle collisions, little is known about their effectiveness with respect to vehicle-pedestrian incidents.

METHODOLOGY

In this study, we trained a set of machine learning models to forecast if a vehicle-pedestrian collision will turn into an injury or fatality, and the most suitable model was used to investigate the contributing features associated with such events with emphasis on the impact of traffic enforcement cameras. In addition to traffic enforcement camera proximity, features associated with the collision, weather, vehicle, victim, and infrastructure are included in the model to reduce unobserved heterogeneity.

RESULTS

Results show that a Linear Discriminant Analysis model surpasses other machine learning models considering the evaluation metrics. Results reveal that the age and gender of the victim, the involvement of larger vehicles in the collision, and the quality of the illumination are the causes associated with pedestrian fatalities. On the other hand, involvement of motorcycles and collisions that occurred in densely populated locations are the causes associated with pedestrian injuries.

CONCLUSIONS

This investigation demonstrates how to articulate machine learning into a vehicle-pedestrian crash analysis to understand the direction and magnitude of covariates in the corresponding severity outcome. Furthermore, it highlights the remarkable effect that traffic enforcement cameras and other features have on vehicle-pedestrian crash severity. These results provide actionable guidance for educational campaigns, enhanced traffic engineering, and infrastructure improvements that could be implemented in the analyzed region to provide safer transportation.

Effects of stricter drunk-driving laws on alcohol-related road traffic death, injury, and crash rates in South Korea: A synthetic counterfactual approach using Bayesian structural time-series models

In December 2018, new drunk-driving laws were enacted in Korea to impose stricter penalties and standards for driving under the influence of alcohol. This study aimed to estimate the effects of stricter drunk-driving laws on alcohol-related road traffic death, injury, and crash rates in Korea. Using police-reported traffic accident data and registered vehicle data from 2013 to 2020, monthly road traffic outcome rates were calculated: the response series involved alcohol-related rates and the non-equivalent control series involved total and non-alcohol-related rates. Based on a controlled interrupted time-series design using Bayesian structural time-series models, effects of the laws on alcohol-related road traffic outcome rates were evaluated. After implementation of these laws, the alcohol-related road traffic crash rate decreased by 14.3% (95% credible interval [CrI] -26.8% to -1.9%), alcohol-related road traffic injury rate by 17.6% (95% CrI -31.6% to -3.8%), and alcohol-related minor road traffic injury rate by 20.2% (95% CrI -32.4% to -7.7%). Alcohol-related road traffic death and severe injury rates also decreased more than the declining trends in the pre-period, but reduced non-significantly by 15.0% (95% CrI -47.2% to 17.3%) and 9.9% (95% CrI -33.9% to 14.5%), respectively. The mixed effectiveness of Korea's new drunk-driving laws on alcohol-related road traffic outcomes suggests that additional strategies are necessary to consistently and effectively reduce alcohol-related road traffic outcomes. More research is needed on ways to enhance the effectiveness of drunk-driving laws.

Effect of Lowering the Blood Alcohol Concentration Limit to 0.03 Among Hospitalized Trauma Patients in Southern Taiwan: A Cross-Sectional Analysis

Background

In June 2013, the legal blood alcohol concentration (BAC) limit for driving was lowered from 0.05 to 0.03 mg/mL in Taiwan. Thus, this study aimed to assess the epidemiological changes in terms of drinking among drivers in southern Taiwan before and after the law was imposed.

Methods

Only patients who had undergone the BAC test at the emergency room were included in the study. The patients during the study period before (n = 2735) and after (n = 2413) the implementation of the law were selected for comparison. Drunk patients were defined as those who had a BAC ≥0.005 and were considered as driving under the influence (DUI) of alcohol. Meanwhile, driving while intoxicated (DWI) was defined as a BAC ≥0.05, which was the level adopted in the new law.

Results

Since the BAC limit lowered to 0.03, the number of DUI patients significantly decreased from 340 (12.4%) to 171 (7.1%), and that of DWI patients significantly reduced from 273 (10.0%) to 146 (6.1%) based on the alcohol test. In addition, after the implementation of the law, the number of associated injuries did not significantly decrease from that before the law was implemented in patients involved in alcohol-related crashes.

Conclusion

After lowering the legal BAC limit from 0.05 to 0.03, responsiveness to the change in law was observed among the studied population. However, such responsiveness may not be observed in some citizens who may need special interventions to help reduce their behavior of drinking and driving.

The increasing role of provincial administrative sanctions in Canadian impaired driving enforcement

Objective: The object of this study is to document the recent shift in Canadian impaired driving enforcement from federal criminal proceedings to provincial administrative sanctions, examine the deterrent impact of these new administrative measures, and review the numerous legal challenges that they have generated.Methods: This article highlights the expanded role of provincial administrative license suspensions (ALSs) and vehicle impoundments (AVIs) in Canadian impaired driving enforcement, summarizes the evidence of their deterrent impact, and discusses the implications of the related Canadian case law.Results: Provincial administrative sanctions have been used increasingly, both to supplement and replace federal impaired driving charges. Recent experience in British Columbia and Alberta illustrates the potential traffic safety benefits of enacting comprehensive impairment-related roadside administrative measures. In 2010, British Columbia enacted a package of roadside administrative sanctions, which included mandatory ALSs, AVIs, monetary penalties, license-reinstatement fees, and remedial programs. A study conducted two years later reported that alcohol-related fatal crashes had fallen by 52%. Alberta enacted similar provisions, and saw alcohol-related fatalities decrease by 46% within six months of the legislation coming into force. Although effective, these new roadside sanctions generated a flurry of legal challenges. The cases indicate that while the provinces have broad leeway, there are legal limits on their authority to impose onerous administrative sanctions on drivers, particularly if they are based on a single roadside alcohol or drug-screening test.Conclusions: With careful drafting, the provinces can enact cost-effective roadside administrative sanctions that have been shown to significantly reduce impaired driving deaths and injuries. The legality of any administrative sanction will likely depend on its severity, the reliability of the test or evidence upon which it is based, and the extent to which the driver has a meaningful opportunity to challenge the decision.

Does the inclusion of vehicle impoundment in provincial short-term administrative driver's license suspension programs reduce total and alcohol-related fatal collisions in Canada?

Objectives: To determine (1) whether the implementation of vehicle impoundment as part of provincial short-term administrative driver licensing suspension (ADLS) programs significantly reduced total and alcohol-related collision fatalities, and (2) if provinces with vehicle impoundment as part of their short-term ADLS programs see greater reductions in total and alcohol-related fatal collisions when compared to provinces without a vehicle impoundment law.Methods: Data on monthly total and alcohol-related fatal collisions from January 2005 to December 2016 are drawn from British Columbia (BC), Alberta (AB), Saskatchewan (SK), Manitoba (MB) and Ontario (ON). Changepoint time series analysis of fatal crashes is employed to detect within-province differences after implementing short-term impoundment programs, and between province differences comparing provinces with short-term impoundment programs (BC, introduced October 2010; AB, introduced July 2012; and SK, introduced July 2014) and those without (ON and MB). Outcome measures are the monthly per capita total and alcohol-related fatal collisions.Results: A significant reduction in per-capita alcohol-related fatal crashes was observed in British Columbia (-47.4%) in the period following the adoption of vehicle impoundment in their short-term ADLS. A significant decrease was also observed in Alberta (-37.5%), though this trend began prior to policy change; no significant effect was observed in per capita alcohol-related fatal crashes rates in Saskatchewan (-6.1%) in the two years following the introduction of vehicle impoundment. Ontario and Manitoba, two provinces without mandatory vehicle impoundment laws, also experienced significant reductions in per-capita alcohol-related fatal crashes between 2005 and 2016 (-36.4% and -35%, respectively).Conclusions: While mandatory vehicle impoundment programs for driving in the "warn" range (0.05%-0.08% BAC) have shown success in reducing fatal crashes in British Columbia, similar reductions in two other provinces with short-term vehicle impoundment were not observed. Moreover, large reductions in fatal crashes were observed in two provinces without vehicle impoundment as part of their short-term ADLS programs. Collectively, these findings suggest that vehicle impoundment, alone, has limited impact on fatal crash rates and that other factors help to explain the observed trends. Further analysis of new vehicle impoundment programs is warranted.

Reprint of "Media reporting of traffic legislation changes in British Columbia (2010)"

INTRODUCTION

In 2010, British Columbia (BC) introduced new traffic laws designed to deter impaired driving, speeding, and distracted driving. These laws generated significant media attention and were associated with reductions in fatal crashes and in ambulance calls and hospital admissions for road trauma.

OBJECTIVE

To understand the extent and type of media coverage of the new traffic laws and to identify how the laws were framed by the media.

METHODS

We reviewed a database of injury related news coverage (May 2010-December 2012) and extracted reports that mentioned distracted driving, impaired driving, or speeding. Articles were classified according to: (i) Type, (ii) Issue discussed, (iii) 'Reference to new laws', and (iv) 'Pro/anti traffic law'. Articles mentioning the new laws were reread and common themes in how the laws were framed were identified and discussed.

RESULTS

Over the course of the study, 1848 articles mentioned distraction, impairment, or speeding and 597 reports mentioned the new laws: 65 against, 227 neutral, and 305 supportive. Reports against the new laws framed them as unfair or as causing economic damage to the entertainment industry. Reports in favor of the new laws framed them in terms of preventing impaired driving and related trauma or of bringing justice to drinking drivers. Growing evidence of the effectiveness of the new laws generated media support.

CONCLUSIONS

BC's new traffic laws generated considerable media attention both pro and con. We believe that this media attention helped inform the public of the new laws and enhanced their deterrent effect.

Can progress in reducing alcohol-impaired driving fatalities be resumed? Results of a workshop sponsored by the Transportation Research Board, Alcohol, Other Drugs, and Transportation Committee (ANB50)

OBJECTIVE

Despite successes in the 1980s and early 1990s, progress in reducing impaired driving fatalities in the United States has stagnated in recent years. Since 1997, the percentage of drivers involved in fatal crashes with illegal blood alcohol concentration (BAC) levels has remained at approximately 20 to 22%. Many experts believe that public complacency, competing social and public health issues, and the lack of political fortitude have all contributed to this stagnation. The number of alcohol-related crashes, injuries, and fatalities is still unacceptable, and most are preventable. The public needs to be aware that the problem presented by drinking drivers has not been solved. Political leaders need guidance on which measures will affect the problem, and stakeholders need to be motivated once again to implement effective strategies.

METHODS

The National Academy of Sciences (NAS) Transportation Research Board (TRB), Alcohol, Other Drugs, and Transportation Committee (ANB50) sponsored a workshop held at the NAS facility in Woods Hole, Massachusetts, on August 24-25, 2015, to discuss the lack of progress in reducing impaired driving and to make recommendations for future progress. A total of 26 experts in research and policy related to alcohol-impaired driving participated in the workshop. The workshop began by examining the static situation in the rate of alcohol-impaired driving fatal crashes to determine what factors may be inhibiting further progress. The workshop then discussed 8 effective strategies that have not been fully implemented in the United States. Workshop participants (16 of the 26) rated their top 3 strategies.

RESULTS

3 strategies received the most support: 1. Impose administrative sanctions for drivers with BACs = 0.05 to 0.08 g/dL. 2. Require alcohol ignition interlocks for all alcohol-impaired driving offenders. 3. Increase the frequency of sobriety checkpoints, including enacting legislation to allow them in the 11 states that currently prohibit them. 5 other important strategies included the following: (1) increase alcohol taxes to raise the price and reduce alcohol consumption; (2) reengage the public and raise the priority of impaired driving; (3) lower the illegal per se BAC limit to 0.05 for a criminal offense; (4) develop and implement in-vehicle alcohol detection systems; and (5) expand the use of screening and brief interventions in medical facilities.

CONCLUSIONS

Each of these strategies is proven to be effective, yet all are substantially underutilized. Each is used in some jurisdictions in the United States or Canada, but none is used extensively. Any one of the 3 strategies implemented on a widespread basis would decrease impaired driving crashes, injuries, and fatalities. Based on the research, all 3 together would have a substantial impact on the problem.

Did Amendments to the Ontario Highway Traffic Act in 2009-2010 Affect the Proportion of Alcohol-Related Motor Vehicle Collisions Seen at a Level I Trauma Centre over a 10-year Period?

OBJECTIVES

To determine if changes to the Ontario Highway Traffic Act (OHTA) in 2009 and 2010 had an effect on the proportion of alcohol-related motor vehicle collisions (MVCs) presenting to a trauma centre over a 10-year period.

METHODS

A retrospective review of the trauma registry at a Level I trauma centre in southwestern Ontario was undertaken. The trauma registry is a database of all trauma patients with an injury severity score (ISS) ≥12 and/or who had trauma team activation. Descriptive statistics were calculated. Interrupted time series analyses with ARIMA modeling were performed on quarterly data from 2004-2013.

RESULTS

A total of 377 drivers with a detectable serum ethanol concentration (SEC) were treated at our trauma centre over the 10-year period, representing 21% of all MVCs. The majority (330; 88%) were male. The median age was 31 years, median SEC was 35.3 mmol/L, and median ISS was 21. A total of 29 (7.7%) drinking drivers died from their injuries after arriving to hospital. There was no change in the proportion of drinking drivers after the 2009 amendment, but there was a significant decline in the average SEC of drinking drivers after changes to the law. There was no difference in the proportion of drinking drivers ≤21 years after introduction of the 2010 amendment for young and novice drivers.

CONCLUSIONS

There was a significance decline in the average SEC of all drinking drivers after the 2009 OHTA amendment, suggesting that legislative amendments may have an impact on drinking before driving behaviour.

A Ten year review of alcohol use and major trauma in a Canadian province: still a major problem

Background

Alcohol plays a significant role in major traumatic injuries. While the role of alcohol in motor vehicle trauma (MVT) is well described, its role and approaches to prevention in other injury mechanisms is less defined.

Methods

A 10 year retrospective examination of Alberta Trauma Registry (ATR) data was conducted on all major trauma patients (age ≥ 9 and ISS ≥ 12) from 2001–2010. The role and prevalence of alcohol is examined.

Results

Of 22,457 patients included in our study, only 60 %(n = 13,552) were screened for alcohol use. Of those screened, 38 %(n = 5,170) tested positive for alcohol with a mean blood alcohol concentration (BAC) of 39.4 ± 21.1 mmol/L. Of the positive screening tests, 82.3 % had BAC levels greater than the common legal driving limit of 17.4 mmol/L (0.08 %). Testing positive was associated with male gender (p < 0.001) and younger age (p < 0.001). The rate of positive alcohol use in major trauma increased from 20.3 % in 2001 to 24.3 % in 2010, corresponding with a screening rate increase from 51.3 % to 61.2 % over the same period. Railway incidents have the highest rate of alcohol involvement (65 %), followed by undetermined-if-accidental/self-inflicted (53.5 %) and assault (49 %); motor vehicle traffic (MVT) incidents had a frequency of 25.4 %.

Conclusions

The prevalence of alcohol use in major trauma appears to be increasing in Alberta but the true extent is still underappreciated. Furthermore, the role of alcohol in non-MVT injuries is significant and deserves further attention. The vast majority of patients involved in alcohol-related trauma are legally intoxicated. Alcohol use continues to be a substantial contributor to major trauma in Alberta, and represents an important opportunity to reduce preventable injuries.

Relationships Between Minimum Alcohol Pricing and Crime During the Partial Privatization of a Canadian Government Alcohol Monopoly

OBJECTIVE

The purpose of this study was to estimate the independent effects of increases in minimum alcohol prices and densities of private liquor stores on crime outcomes in British Columbia, Canada, during a partial privatization of off-premise liquor sales.

METHOD

A time-series cross-sectional panel study was conducted using mixed model regression analysis to explore associations between minimum alcohol prices, densities of liquor outlets, and crime outcomes across 89 local health areas of British Columbia between 2002 and 2010. Archival data on minimum alcohol prices, per capita alcohol outlet densities, and ecological demographic characteristics were related to measures of crimes against persons, alcohol-related traffic violations, and non-alcohol-related traffic violations. Analyses were adjusted for temporal and regional autocorrelation.

RESULTS

A 10% increase in provincial minimum alcohol prices was associated with an 18.81% (95% CI: ±17.99%, p < .05) reduction in alcohol-related traffic violations, a 9.17% (95% CI: ±5.95%, p < .01) reduction in crimes against persons, and a 9.39% (95% CI: ±3.80%, p < .001) reduction in total rates of crime outcomes examined. There was no significant association between minimum alcohol prices and non-alcohol-related traffic violations (p > .05). Densities of private liquor stores were not significantly associated with alcohol-involved traffic violations or crimes against persons, though they were with non-alcohol-related traffic violations.

CONCLUSIONS

Reductions in crime events associated with minimum-alcohol-price changes were more substantial and specific to alcohol-related events than the countervailing increases in densities of private liquor stores. The findings lend further support to the application of minimum alcohol prices for public health and safety objectives.

Media reporting of traffic legislation changes in British Columbia (2010)

INTRODUCTION

In 2010, British Columbia (BC) introduced new traffic laws designed to deter impaired driving, speeding, and distracted driving. These laws generated significant media attention and were associated with reductions in fatal crashes and in ambulance calls and hospital admissions for road trauma.

OBJECTIVE

To understand the extent and type of media coverage of the new traffic laws and to identify how the laws were framed by the media.

METHODS

We reviewed a database of injury related news coverage (May 2010-December 2012) and extracted reports that mentioned distracted driving, impaired driving, or speeding. Articles were classified according to: (i) Type, (ii) Issue discussed, (iii) 'Reference to new laws', and (iv) 'Pro/anti traffic law'. Articles mentioning the new laws were reread and common themes in how the laws were framed were identified and discussed.

RESULTS

Over the course of the study, 1848 articles mentioned distraction, impairment, or speeding and 597 reports mentioned the new laws: 65 against, 227 neutral, and 305 supportive. Reports against the new laws framed them as unfair or as causing economic damage to the entertainment industry. Reports in favor of the new laws framed them in terms of preventing impaired driving and related trauma or of bringing justice to drinking drivers. Growing evidence of the effectiveness of the new laws generated media support.

CONCLUSIONS

BC's new traffic laws generated considerable media attention both pro and con. We believe that this media attention helped inform the public of the new laws and enhanced their deterrent effect.

An evaluation of evidence-based paediatric injury prevention policies across Canada

BACKGROUND

Policies to reduce injury among Canadians can be controversial and there is variability in the enactment of injury prevention laws across the country. In general, laws are most effective when they are based on good research evidence, supported by widespread public awareness and education, and maintained by consistent enforcement strategies. The purpose of this study was to document and compare key informants' perceptions of the quality, awareness, and enforcement of three evidence-based paediatric injury prevention policies (bicycle helmet legislation, child booster seat legislation, graduated driver licensing) among Canadian provinces and territories.

METHODS

We identified best practices related to each policy, then developed an online survey to ascertain the extent to which each jurisdiction's policy aligned with best practices, whether experts believed that the public was aware of the policy and whether it was enforced. The survey was distributed using a snowball sampling strategy to key informants across Canada.

RESULTS

Thirty-eight key informants responded to the bicycle helmet survey, with 73 and 35 key informants for the booster seat and graduated driver licensing surveys, respectively. Respondent's perceptions of the policies varied substantially. Key informants indicated that residents are not always aware of legislation, and legislation is not consistently enforced. These results suggest that child health policy is not always guided by evidence.

CONCLUSIONS

There was variation between evidence and the policies related to paediatric injury prevention among Canadian provinces and territories. Experts generally rate their policies more highly when they align with evidence and best practice. There is room for improvement and harmonization of injury prevention policies.

Evaluating the impact of the alcohol act on off-trade alcohol sales: a natural experiment in Scotland

BACKGROUND AND AIMS

A ban on multi-buy discounts of off-trade alcohol was introduced as part of the Alcohol Act in Scotland in October 2011. The aim of this study was to assess the impact of this legislation on alcohol sales, which provide the best indicator of population consumption.

DESIGN, SETTING AND PARTICIPANTS

Interrupted time-series regression was used to assess the impact of the Alcohol Act on alcohol sales among off-trade retailers in Scotland. Models accounted for underlying seasonal and secular trends and were adjusted for disposable income, alcohol prices and substitution effects. Data for off-trade retailers in England and Wales combined (EW) provided a control group.

MEASUREMENTS

Weekly data on the volume of pure alcohol sold by off-trade retailers in Scotland and EW between January 2009 and September 2012.

FINDINGS

The introduction of the legislation was associated with a 2.6% (95% CI = -5.3 to 0.2%, P = 0.07) decrease in off-trade alcohol sales in Scotland, but not in EW (-0.5%, 95% CI = -4.6 to 3.9%, P = 0.83). A statistically significant reduction was observed in Scotland when EW sales were adjusted for in the analysis (-1.7%, 95% CI = -3.1 to -0.3%, P = 0.02). The decline in Scotland was driven by reduced off-trade sales of wine (-4.0%, 95% CI = -5.4 to -2.6%, P < 0.001) and pre-mixed beverages (-8.5%, 95% CI = -12.7 to -4.1%, P < 0.001). There were no associated changes in other drink types in Scotland, or in sales of any drink type in EW.

CONCLUSIONS

The introduction of the Alcohol Act in Scotland in 2011 was associated with a decrease in total off-trade alcohol sales in Scotland, largely driven by reduced off-trade wine sales.

Reduction in fatalities, ambulance calls, and hospital admissions for road trauma after implementation of new traffic laws

OBJECTIVES

We evaluated the public health benefits of traffic laws targeting speeding and drunk drivers (British Columbia, Canada, September 2010).

METHODS

We studied fatal crashes and ambulance dispatches and hospital admissions for road trauma, using interrupted time series with multiple nonequivalent comparison series. We determined estimates of effect using linear regression models incorporating an autoregressive integrated moving average error term. We used neighboring jurisdictions (Alberta, Saskatchewan, Washington State) as external controls.

RESULTS

In the 2 years after implementation of the new laws, significant decreases occurred in fatal crashes (21.0%; 95% confidence interval [CI]=15.3, 26.4) and in hospital admissions (8.0%; 95% CI=0.6, 14.9) and ambulance calls (7.2%; 95% CI=1.1, 13.0) for road trauma. We found a very large reduction in alcohol-related fatal crashes (52.0%; 95% CI=34.5, 69.5), and the benefits of the new laws are likely primarily the result of a reduction in drinking and driving.

CONCLUSIONS

These findings suggest that laws calling for immediate sanctions for dangerous drivers can reduce road trauma and should be supported.

The effectiveness of a 0.05 blood alcohol concentration (BAC) limit for driving in the United States

The National Transportation Safety Board recently recommended that states establish a per se blood alcohol concentration (BAC) limit of 0.05 or lower for all drivers who are not already required to adhere to lower BAC limits in a national effort to reduce alcohol-impaired driving. There is strong evidence for adopting this recommendation. A comprehensive review of the literature on BAC limits was conducted. The research indicates that virtually all drivers are impaired regarding at least some driving performance measures at a 0.05 BAC. The risk of being involved in a crash increases significantly at 0.05 BAC and above. The relative risk of being killed in a single-vehicle crash with BACs of 0.05-0.079 is 7-21 times higher than for drivers at 0.00 BAC. Lowering the BAC limit from 0.08 to 0.05 has been a proven effective countermeasure in numerous countries around the world. Most Americans do not believe a person should drive after having two or three drinks in 2 hours. It takes at least four drinks for the average 170-pound male to exceed 0.05 BAC in 2 hours (three drinks for the 137-pound female). Most industrialized nations have established a 0.05 BAC limit or lower for driving. Progress in reducing the proportion of drivers in fatal crashes with illegal BACs has stalled over the past 15 years. Lowering the BAC limit for driving from the current 0.08 to 0.05 has substantial potential to reduce the number of people who drink and drive in the United States and get involved in fatal crashes.