Original Articles
The effect of random alcohol screening in reducing motor vehicle crash injuries

https://doi.org/10.1016/S0749-3797(98)00116-0Get rights and content

Abstract

Objective: Programs that randomly stop drivers to detect alcohol use have been introduced as a deterrence measure for drinking and driving. The objective of this review is to determine if this random screening reduces fatalities and injuries. The two types of random screening programs included are Random Breath Testing and Sobriety Checkpoints.

Methods: Fourteen studies met inclusion criteria, which required an evaluation of a random screening program with a control population or baseline comparison. Proportional decreases in total or alcohol-related fatalities or injuries were the outcome of interest.

Main results: All fourteen studies found that random screening was effective in reducing fatalities and injuries. The decreases found had wide variation, but did not depend on the size of the population. Alcohol-related fatalities generally showed the greatest decreases, ranging from 8% to 71%. The few multivariate analyses showed that random screening significantly reduced crashes and injuries.

Conclusions: Random screening appears to be effective in a wide range of both United States and Australian populations. Although there are many limitations to the studies reviewed, such as the difficulty in determining alcohol involvement and the inability to control for the presence of other drunk driving reduction programs, the weight of the evidence indicates that random screening reduces fatalities and injuries. There was some disagreement among studies as to how long the effects of random alcohol screening can be sustained and the level of enforcement necessary, and these remain questions to be answered.

Introduction

Alcohol has long been cited as one of the most significant risk factors for vehicle crashes in the United States and other developed countries, and is increasingly recognized as a factor in developing countries. In the United States, alcohol involvement was first accurately measured nationally in 1982, when 57% of motor vehicle fatalities were found to be alcohol-related.1 The proportion of fatalities in alcohol-related crashes has decreased steadily to 40.9% in 1996.1 In Australia in the early 1980s, road crashes were the single largest cause of death for Australians up to 35 years of age, with as many as 41.5% involving alcohol.2, 3 Australia has also seen a decrease in alcohol involvement in the last several years. Even though most developed countries have experienced decreases in alcohol-involved crashes in the 1980s and early 1990s, alcohol remains one of the most consistent causes of roadway fatalities and injuries.

Crashes involving alcohol are most predominant in late night hours and are often characterized by single vehicle crashes. In the United States in 1996, 42% of drivers in night crashes had been drinking compared to only 10% of drivers in day crashes.1 Among single vehicle crashes causing a fatality, 50.0% of crashes were alcohol-related compared to 29.8% of multiple vehicle crashes. Holidays are common periods for increased incidence of alcohol-involved motor vehicle crashes. In 1996, over 50% of the fatal crashes occurring during holidays were alcohol-related.1 Because direct measures of alcohol use in non-fatal crashes are often not available, these types of crashes are often used as a proxy.

Although alcohol remains one of the most common contributing causes of motor vehicle crashes, the number and rate of alcohol-related crashes have been reduced in many countries. Attempts to reduce alcohol-related crashes have been multifaceted, including education campaigns, enforcement, and legislation. One measure utilized by several countries to decrease drinking and driving through deterrence and enforcement is random alcohol screening of drivers. The key elements in random screening are legislation implementing its use, strong enforcement of the program with strict and definite penalties, public education to raise awareness of the program, and the perception that random screening is truly random and ubiquitous.4 In order to be considered random screening, vehicles must be stopped randomly without a preliminary suspicion of alcohol use. The measure itself has met with much controversy, especially in the United States where drivers have asserted their right to refuse testing without a reasonable suspicion of alcohol use. Thus, the exact methodology under which random screening has been introduced has varied according to local laws.

The evaluation data for this review came from two countries: Australia and the United States. Because of differences in random screening laws, there are variations in the programs of these two countries although the objectives remain the same. In the Random Breath Testing (RBT) program in Australia, cars are stopped at checkpoints or by roving units, regardless of suspicion of alcohol use, and a breath alcohol test is administered. In the United States, sobriety checkpoints stop cars randomly, and breath alcohol tests are administered only if the use of alcohol is suspected through odor, actions, presence of containers, or other means. The key feature of both interventions is that vehicles are stopped regardless of the suspicion of alcohol use, but in the Australian RBT all drivers who are stopped receive a breath test while only drivers suspected of drinking are tested in the United States. In both countries, police also actively stop vehicles because the driver is exhibiting signs of alcohol use. This type of enforcement was not included in this review.

Random alcohol screening works through two dependent pathways, both of which must be present for an effective program. The first pathway is deterrence, in which drivers perceive that they will be caught through the random screening program if they drink. This component affects all members of communities in which random screening is implemented. The second pathway is through enforcement, which leads to the detection of drunk drivers and the application of penalties for drinking and driving. Only vehicles stopped in the random screening programs are affected by the enforcement pathway.

Most random screening programs are established in areas identified as having a high incidence of alcohol-related crashes, and some programs have utilized a “blitz” approach in which random screening is conducted over short periods known to have alcohol-related fatalities. For the remainder of this review, random screening will refer to both RBT and sobriety checkpoint configurations, and the specific configuration will be mentioned when necessary.

This review was undertaken to synthesize results of studies evaluating random screening programs in order to understand their role in decreasing motor vehicle–related deaths and injuries and alcohol-related deaths and injuries.

Section snippets

Search strategy

A detailed description of the search strategy is provided by Rivara et al.5

Populations under study

The populations under study included all members of communities where random alcohol screening had been implemented. Although random screening focuses on reducing the number of drinking drivers, individuals other than drivers are at risk for alcohol-related crashes and injuries. Thus, the impact of random screening on crashes and injuries was selected as the outcome for this review. There were no restrictions for

Description of included studies

The included studies are summarized in Table 1.2, 3, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30

Methodologic quality of studies

The included studies had some common flaws. The studies were all ecologic in nature and there was a lack of multivariate analyses to control for other deterrence programs often implemented at the same time and in the same population as the random screening programs. One study attempted to determine the effects of the implementation of random screening laws in the presence of other laws to reduce

Discussion

All studies found that the implementation of random screening was followed by a period of reduced fatalities, injuries, and/or alcohol-related fatalities and injuries. Although none of the studies could draw a causal connection, the agreement in findings does support the effectiveness of this approach. The five studies that controlled for time trends and other factors predicting motor vehicle crashes had relatively similar findings even though several different communities and analytic

Conclusions

Based on the consistency of findings, there appears to be enough evidence to support the implementation of random screening programs to deter drunk driving and related motor vehicle crashes. The strength of this evidence is reduced by some common limitations in the study designs and data collected. Most of the evidence is ecologic, which reduces the ability to draw causal connections. Furthermore, most of the communities introducing random screening also introduced other measures to reduce

Supplementary data

Acknowledgements

This work was supported by the Southern California Injury Prevention Research Center and the Harborview Injury Prevention Research Center. The author would like to acknowledge the assistance of Larry Chu, MPH, and the invaluable input of Diane Thompson, MPH, Fred Rivara, PhD, and Ellen MacKenzie, PhD.

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