The behavioral economics of drunk driving

Rideshare Trips and Alcohol-Involved Motor Vehicle Crashes in Chicago

OBJECTIVE

Rideshare companies such as Uber and Lyft have substantially changed transportation markets in the United States and globally. The aim of this study was to examine whether ridesharing is associated with reductions in alcohol-involved crashes.

METHOD

This case-series study used highly spatially and temporally resolved trip-level rideshare data and motor vehicle crash data from the Chicago Data Portal from November 2018 to December 2019. The units of analysis were motor vehicle crashes in Chicago. Events of interest were 962 crashes that police indicated were alcohol involved. The comparison group was 962 non-alcohol-involved crashes that occurred in the same census tract, matched 1:1. The exposure of interest was the density per square mile of rideshare trips that were in progress at the time of the crash, calculated using a kernel density function around the estimated route paths of active trips. A conditional logistic regression compared alcohol involvement to rideshare trip density while adjusting for matching and relevant time-varying covariates (taxi trips, precipitation, temperature, holidays).

RESULTS

Mean rideshare trip density was 69.0 per square mile (SD = 129.7) at the time and location of alcohol-involved crashes and 105.7 per square mile (SD = 192.6) at the time and location of non-alcohol-involved crashes. After controlling for covariates, the conditional logistic regression model identified that a standard deviation increase in rideshare trips per square mile at the crash location was associated with 23% decreased odds that the crash location was alcohol involved (odds ratio = 0.771; 95% confidence interval [0.594, 0.878]).

CONCLUSIONS

Ridesharing may replace motor vehicle trips by alcohol-impaired drivers.

None for the Road? Stricter Drink Driving Laws and Road Accidents

Reducing drink drive limits is generally regarded an effective strategy to save lives on the road. Using several new administrative data sources, we evaluate the effect of a stricter limit introduced in Scotland in 2014. This reduction had no effect on drink driving and road collisions. Estimates from a supply-of-offenses function suggests that the reform did not have much ex-ante scope for sizeable effects. The unavailability of cheaper alternative means of transportation and weak law enforcement seem to have been the main channels behind the lack of an impact. We find no externality on a wide range of domains, from alcohol consumption to criminal activities other than drink driving.

A Natural Experiment to Test the Effect of Sanction Certainty and Celerity on Substance-Impaired Driving: North Dakota's 24/7 Sobriety Program

OBJECTIVES

Evaluate the deterrent effect of a program that increases the certainty and celerity of sanction for arrestees ordered to abstain from alcohol and other drugs on substance-impaired driving arrests.

METHODS

We examine participant compliance with orders to abstain from alcohol and other drug use via breathalyzer, body-worn continuous alcohol monitoring (CAM) devices, transdermal drug patches, and urinalyses. We then evaluate the impact of the 24/7 Sobriety program on substance-impaired driving arrests. Using variation across counties in the timing of program implementation in North Dakota as a natural experiment, we use differences-in-differences fixed effects Poisson regressions to measure the program's effect on county-level arrests for substance-impaired driving.

RESULTS

Over half of participants ordered to abstain from substance use complete 24/7 Sobriety without a detected substance use event. At the county level, the program is associated with a 9 percent reduction in substance-impaired driving arrests after accounting for the impact of oil exploration in the Bakken region, law enforcement intensity, alcohol availability, whether the state's large universities were in session, and socio-demographic characteristics.

CONCLUSIONS

The results suggest frequent monitoring combined with increased sanction celerity deters substance use-involved crime. While the results are generally consistent with an earlier study of 24/7 Sobriety in another state, differences in the study outcome measures and implementation choices across states make direct comparisons difficult. More can be learned by conducting randomized controlled trials that vary time on program, testing technology, and/or level of sanction.

Life-threatening alcohol-related traffic crashes in adverse weather: a double-matched case-control analysis from Canada

IMPORTANCE

Drunk driving is a major cause of death in North America, yet physicians rarely counsel patients on the risks of drinking and driving.

OBJECTIVE

To test whether the risks of a life-threatening alcohol-related traffic crash were further accentuated by adverse weather.

DESIGN

Double matched case-control analysis of hospitalised patients.

SETTING

Canada's largest trauma centre between 1 January 1995 and 1 January 2015.

PARTICIPANTS

Patients hospitalised due to a life-threatening alcohol-related traffic crash.

EXPOSURE

Relative risk of a crash associated with adverse weather estimated by evaluating the weather at the place and time of the crash (cases) compared with the weather at the same place and time a week earlier and a week later (controls).

RESULTS

A total of 2088 patients were included, of whom the majority were drivers injured at night. Adverse weather prevailed among 312 alcohol-related crashes and was significantly more frequent compared with control circumstances. The relative risk of a life-threatening alcohol-related traffic crash was 19% higher during adverse weather compared with normal weather (95% CI: 5 to 35, p=0.006). The absolute increase in risk amounted to 43 additional crashes, extended to diverse groups of patients, applied during night-time and daytime, contributed to about 793 additional patient-days in hospital and was distinct from the risks for drivers who were negative for alcohol.

CONCLUSIONS

Adverse weather was associated with an increased risk of a life-threatening alcohol-related traffic crash. An awareness of this risk might inform warnings to patients about traffic safety and counselling alternatives to drinking and driving.

Decision Making and Alcohol: Health Policy Implications

Many negative outcomes associated with alcohol consumption stem from individual decision making, such as the decision whether or not to drive after drinking. Understanding biases in decision making as they relate to alcohol, and measuring variability in decision strategies across individuals, can be a tool for improving policy. For alcohol-related policy, both addiction and the acute effects of intoxication are potential sources of bias or heterogeneity in decision strategy, and we provide a brief primer on how they can affect decision making. We then discuss two alcohol policy domains, alcohol impaired driving and excessive consumption. We review potential implications of major findings in decision making research for each of these domains, and point out how policy could take account of biases and variability in decision making.

Present bias and health

This study uses a dynamic discrete choice model to examine the degree of present bias and naivete about present bias in individuals' health care decisions. Clinical guidelines exist for several common chronic diseases. Although the empirical evidence for some guidelines is strong, many individuals with these diseases do not follow the guidelines. Using persons with diabetes as a case study, we find evidence of substantial present bias and naivete. Counterfactual simulations indicate the importance of present bias and naivete in explaining low adherence rates to health care guidelines.

Washington State Spirits Privatization: How Satisfied were Liquor Purchasers Before and After, and by Type of Retail Store in 2014?

BACKGROUND

In 2012 Washington State ended a wholesale/retail monopoly on liquor, permitting sale of spirits in stores with > 10,000 square feet. Implementation resulted in average price increases, but also five times the stores selling liquor.

OBJECTIVES

As part of a privatization evaluation, we studied pre-post and between-store-type purchase experiences.

METHODS

A 2010 Washington State Liquor Control Board (LCB) survey of liquor purchasers (n = 599), and the 2014 baseline of a repeated telephone survey (1,202 residents; n = 465 purchasers), each included 10 LCB questions on satisfaction with purchase experiences, each attribute with graded response scale A = 4 to D = 1 and F (0 = fail). Analyses used t-tests for satisfaction differences by time and analysis of variance (ANOVA) for 2014 between-store satisfaction-level differences.

RESULTS

Five purchase features were rated more favorably after privatization (ps < .05-.001), including product supply, staff professionalism, location convenience, store hours, and prices (though price rated lowest both times); selection offered, courtesy, and checkout speed were unaltered, and number of staff and staff knowledge declined (both p < .001). Eight consumer experiences differed by store type: five satisfaction aspects (supply, selection, number of staff, operating hours, and checkout speed) were highest for liquor superstores, while location convenience favored grocery and drug stores, and price satisfaction favored wholesale (Costco) stores, with staff knowledge highest at liquor stores.

CONCLUSIONS

Satisfaction with liquor purchases increased after privatization for half the consumer experiences. Availability (location convenience and store hours) was important to liquor purchasers. Such results are relevant to sustained support for the policy of privatizing spirits retail monopolies.

Drinking-and-Driving-Related Cognitions Mediate the Relationship Between Alcohol Demand and Alcohol-Impaired Driving

OBJECTIVE

Elevated behavioral economic demand for alcohol has been shown to be associated with drinking and driving in college students. The present study sought to clarify the underlying mechanisms of this relationship by examining whether drinking-and-driving-related cognitions (e.g., attitudes, perceptions, and normative beliefs) mediate the association between alcohol demand and drinking and driving.

METHOD

A total of 134 young adult social drinkers completed an alcohol purchase task and measures of perceived dangerousness of drinking and driving, normative beliefs about drinking and driving, and perceived driving limit (i.e., perceived number of drinks one could consume and still drive safely). The frequency of drinking and driving in the past year was assessed via self-report.

RESULTS

Individuals who reported drinking and driving exhibited greater alcohol demand (intensity, Omax, and elasticity) compared with those who did not engage in drinking and driving. Increased demand was also correlated with more favorable drinking-and-driving cognitions. Indirect effects tests revealed that perceived driving limit partially mediated the relationship between alcohol demand and drinking-and-driving behavior, even after accounting for drinking level, sex, and delay discounting.

CONCLUSIONS

These findings provide further support for the utility of behavioral economic theory in understanding drinking-and-driving behavior. In particular, they provide evidence for one mechanism-drinking-and-driving-related cognitions-by which alcohol demand influences drinking and driving. Additional research using longitudinal and experimental designs is required to confirm this model and to identify other potential mediators.

Doctor-patient differences in risk and time preferences: A field experiment

We conduct a framed field experiment among patients and doctors to test whether the two groups have similar risk and time preferences. We elicit risk and time preferences using multiple price list tests and their adaptations to the healthcare context. Risk and time preferences are compared in terms of switching points in the tests and the structurally estimated behavioural parameters. We find that doctors and patients significantly differ in their time preferences: doctors discount future outcomes less heavily than patients. We find no evidence that doctors and patients systematically differ in their risk preferences in the healthcare domain.

Drinking and Driving among University Students in 22 Low, Middle Income and Emerging Economy Countries

BACKGROUND

The aim of this study was investigate drinking, driving, and socio-behavioral factors among university students in low and middle income and emerging economy countries.

METHODS

Using anonymous questionnaires, data were collected from 18476 university students, of which 15151 (82.0%) were drivers of a car or motorcycle (41.3% men and 58.7% women), with a mean age of 20.7 years (SD=2.9), from 22 countries across Africa, Asia and Americas.

RESULTS

Overall, 17.3% reported to have been driving a car or motorcycle after having had too much to drink in the past 12 months, ranging from below 5% in Bangladesh, Indonesia and Kyrgyzstan to above 35% in China, Singapore and Thailand. In multivariate logistic regression analysis, among both men and women, earlier year of study, living in an upper middle income or high income country (OR=3.58, CI=3.00-4.27 and OR=2.95, CI=2.52-3.46), low intrinsic religiosity (OR=0.67, CI=0.54-0.83 and OR=0.34, CI=0.28-0.42), injury from motorcycle accidents (OR=4.29, CI=2.69-6.82 and OR=3.24, CI=2.26-4.63), and weak belief in the importance of not drinking (OR=1.78, CI=1.50-2.11 and OR=1.61, CI=1.37-1.88) and driving were associated with drinking and driving. Further, among men, older age (OR=1.04, CI=1.01-1.07), binge drinking (OR=1.53, CI=1.27-1.86) and illicit drug use (OR=1.22, CI=1.01-1.47), and among women, younger age (OR=0.95, CI=0.97-0.98), and a lower country BAC limit (OR=0.01, CI=0.001-0.18) was associated with drinking and driving.

CONCLUSION

This study confirms low to high levels of drinking and driving in different cultures across Africa, Asia and the Americas. Various factors identified can be used to guide interventions to reduce drinking and driving among university students.

Do preferences of drinker-drivers differ?

Why people engage in illegal activities is not well understood. Using data collected for this research from eight cities in four states, this study investigates alternative explanations as to why people drive while intoxicated (DWI). We find that preferences and subjective beliefs about arrest/incarceration of persons who drink and drive do differ systematically from others in terms of benefits and costs of drink and driving, and in their risk tolerance. While most findings imply that DWI is a deliberate choice, we do find that drinker drivers tend to be more impulsive and lack self-control in their drinking.

The effects of participation level on recidivism: a study of drug treatment courts using propensity score matching

Background

Empirical evidence has suggested that drug treatment courts (DTCs) reduce re-arrest rates. However, DTC program completion rates are low and little is known about the effectiveness of lower levels of program participation.

Objectives

We examined how DTC program referral, enrollment without completion, and completion, affected re-arrest rates during a two-year follow-up.

Research design

We used statewide North Carolina data from criminal courts merged with DTC data. Propensity score matching was used to select comparison groups based on demographic characteristics, criminal histories, and drug of choice (when available). Average treatment effects on the treated were computed.

Measures

DTC participation levels included referral without enrollment, (n = 2,174), enrollment without completion (n = 954), and completion (n = 747). Recidivism measured as re-arrest on a substance-related charge, on a violent offense charge not involving an allegation of substance abuse, and on any charge (excluding infractions) was examined by felony and misdemeanor status during a two-year follow-up period.

Results

Re-arrest rates were high, 53–76 percent. In general, re-arrest rates were similar for individuals who were referred but who did not enroll and a matched comparison group consisting of individuals who were not referred. In contrast, enrollees who did not complete had lower re-arrest rates than a matched group of individuals who were referred but did not enroll, for arrests on any charge, on any felony charge, and on substance-related charges (felonies and misdemeanors). Finally, relative to persons who enrolled but did not complete, those who completed had lower re-arrest rates on any charge, any felony charge, any misdemeanor charge, any substance-related charge, any substance-related misdemeanor or felony charge, and any violent felony charge.

Conclusions

Enrolling in a DTC, even without completing, reduced re-arrest rates. Given the generally low DTC completion rate, this finding implies that only examining effects of completion underestimates the benefits of DTC programs.