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Per Se Blood Alcohol Content (BAC) Limit of 0.05

Adult Criminal Justice
Benefit-cost methods last updated December 2024.  Literature review updated July 2025.
Per se impaired driving laws make it illegal to drive with a blood alcohol content (BAC) at or over a specified limit. By 2005, all states, the District of Columbia, and Puerto Rico had set per se limits at 0.08 g/dl. States are now exploring the potential roadway safety impacts of reducing per se thresholds to 0.05 g/dl. Lower thresholds are more common outside of the U.S.; Utah is the only state to have adopted a 0.05 g/dl BAC per se law. This review explores the evidence for the effectiveness of lowering per se BAC limits to 0.05 g/dl or less.
 
ALL
BENEFIT-COST
META-ANALYSIS
CITATIONS
For an overview of WSIPP's Benefit-Cost Model, please see this guide. The estimates shown are present value, life cycle benefits and costs. All dollars are expressed in the base year chosen for this analysis (2023).  The chance the benefits exceed the costs are derived from a Monte Carlo risk analysis. The details on this, as well as the economic discount rates and other relevant parameters are described in our Technical Documentation.
Benefit-Cost Summary Statistics Per Participant
Benefits to:
Taxpayers $19 Benefits minus costs $511
Participants $293 Benefit to cost ratio $330.14
Others $100 Chance the program will produce
Indirect $100 benefits greater than the costs 99%
Total benefits $512
Net program cost ($2)
Benefits minus cost $511

^^WSIPP does not include this outcome when conducting benefit-cost analysis for this program.

Meta-analysis is a statistical method to combine the results from separate studies on a program, policy, or topic to estimate its effect on an outcome. WSIPP systematically evaluates all credible evaluations we can locate on each topic. The outcomes measured are the program impacts measured in the research literature (for example, impacts on crime or educational attainment). Treatment N represents the total number of individuals or units in the treatment group across the included studies.

An effect size (ES) is a standard metric that summarizes the degree to which a program or policy affects a measured outcome. If the effect size is positive, the outcome increases. If the effect size is negative, the outcome decreases. See Estimating Program Effects Using Effect Sizes for additional information on how we estimate effect sizes.

The effect size may be adjusted from the unadjusted effect size estimated in the meta-analysis. Historically, WSIPP adjusted effect sizes to some programs based on the methodological characteristics of the study. For programs reviewed in 2024 or later, we do not make additional adjustments, and we use the unadjusted effect size whenever we run a benefit-cost analysis.

Research shows the magnitude of effects may change over time. For those effect sizes, we estimate outcome-based adjustments, which we apply between the first time ES is estimated and the second time ES is estimated. More details about these adjustments can be found in our Technical Documentation.

Meta-Analysis of Program Effects
Outcomes measured Treatment age No. of effect sizes Treatment N Effect sizes (ES) and standard errors (SE) used in the benefit-cost analysis Unadjusted effect size (random effects model)
First time ES is estimated Second time ES is estimated
ES SE Age ES SE Age ES p-value
Crime
Involvement in the criminal justice system (e.g., arrests, charges, convictions, incarceration) measured through administrative records (e.g. court records, arrests) or self-report.
 31 1 171 -0.046 0.143 31 -0.046 0.143 39 -0.046 0.747
Any crash^^
Reported crashes at all injury and damage levels. Includes fatal, injury, and property damage crashes.
31 1 1947 -0.373 0.032 31 -0.373 0.032 40 -0.373 0.001
Fatal crash
Reported crashes with at least one fatality.
31 6 7586 -0.103 0.078 31 -0.103 0.078 40 -0.103 0.187
Any non-fatal injury crash
Reported crashes at all injury levels except fatal. Includes all injury levels (serious injury, minor injury, possible injury).
31 2 68 -0.472 0.222 31 -0.472 0.222 40 -0.472 0.034
Injury and fatal crash^^
Reported crashes that result in a fatality, serious injury, or minor injury.
31 4 7492 -0.106 0.016 31 -0.106 0.016 40 -0.106 0.001
Fatal crash (alcohol related)^^
Reported crashes with at least one fatality involving alcohol, measured through driver BAC or a commonly accepted proxy (e.g., single-vehicle nighttime crashes).
31 3 275 -0.179 0.123 31 -0.179 0.123 40 -0.179 0.146
Any crash (alcohol related)^^
Reported crashes at all levels (fatal, injury, and property damage) involving alcohol, measured through driver BAC or a commonly accepted proxy (e.g., single-vehicle nighttime crashes).
31 3 3244 -0.102 0.025 31 -0.102 0.025 40 -0.102 0.001
Property damage only crash
Reported crashes that only cause property damage but no reported injuries or fatalities.
31 1 1947 -0.444 0.032 31 -0.444 0.032 40 -0.444 0.001
1In addition to the outcomes measured in the meta-analysis table, WSIPP measures benefits and costs estimated from other outcomes associated with those reported in the evaluation literature. For example, empirical research demonstrates that high school graduation leads to reduced crime. These associated measures provide a more complete picture of the detailed costs and benefits of the program.

2“Others” includes benefits to people other than taxpayers and participants. Depending on the program, it could include reductions in crime victimization, the economic benefits from a more educated workforce, and the benefits from employer-paid health insurance.

3“Indirect benefits” includes estimates of the net changes in the value of a statistical life and net changes in the deadweight costs of taxation.
Detailed Monetary Benefit Estimates Per Participant
Affected outcome: Resulting benefits:1 Benefits accrue to:
Taxpayers Participants Others2 Indirect3 Total
Crime Criminal justice system $7 $0 $5 $3 $15
Property damage only crash Total costs of property damage only crash $3 $9 $26 $0 $38
Fatal crash Total costs of fatal crash $2 $33 $14 $97 $146
Any non-fatal injury crash Total costs of nonfatal injury crash $7 $251 $55 $0 $314
Program cost Adjustment for deadweight cost of program $0 $0 $0 ($1) ($1)
Totals $19 $293 $100 $100 $512
Click here to see populations selected
Detailed Annual Cost Estimates Per Participant
Annual cost Year dollars Summary
Program costs $0 2025 Present value of net program costs (in 2023 dollars) ($2)
Comparison costs $0 2025 Cost range (+ or -) 30%
"Implementation of lower per se blood alcohol content (BAC) laws tends to have limited cost implications. Implementation is typically associated with a media campaign to educate people on the change to the law. We used cost estimates developed by the Washington Transportation Safety Commission to estimate the cost of conducting a statewide information campaign to raise awareness about changes in per se law and the impact of impaired driving. Although there may be some criminal legal system costs associated with enforcement, arrest, prosecution, and incarceration, these costs can be difficult to estimate. Early evidence from Utah suggests that there was not a substantial increase in arrests after reducing per se thresholds to 0.05 g/dl. For this reason, we omit criminal legal system costs from our program cost estimates. "
The figures shown are estimates of the costs to implement programs in Washington. The comparison group costs reflect either no treatment or treatment as usual, depending on how effect sizes were calculated in the meta-analysis. The cost range reported above reflects potential variation or uncertainty in the cost estimate; more detail can be found in our Technical Documentation.
Benefits Minus Costs
Benefits by Perspective
Taxpayer Benefits by Source of Value
Benefits Minus Costs Over Time (Cumulative Discounted Dollars)
The graph above illustrates the estimated cumulative net benefits per-participant for the first fifty years beyond the initial investment in the program. We present these cash flows in discounted dollars. If the dollars are negative (bars below $0 line), the cumulative benefits do not outweigh the cost of the program up to that point in time. The program breaks even when the dollars reach $0. At this point, the total benefits to participants, taxpayers, and others, are equal to the cost of the program. If the dollars are above $0, the benefits of the program exceed the initial investment.

Citations Used in the Meta-Analysis

Blais, É., Bellavance, F., Marcil, A., & Carnis, L. (2015). Effects of introducing an administrative .05% blood alcohol concentration limit on law enforcement patterns and alcohol-related collisions in Canada. Accident Analysis & Prevention, 82, 101–111.

Guimarães, A.G., & da Silva, AR. (2019). Impact of regulations to control alcohol consumption by drivers: An assessment of reduction in fatal traffic accident numbers in the Federal District, Brazil. Accident Analysis and Prevention, 127, 110–117.

Henstridge, J., Homel, R., & Mackay, P. (1997). The long-term effects of random breath testing in four Australian states: A time series analysis (Report No. CR 162). Federal Office of Road Safety.

Kudła, J., Podsiadło, A., & Woźniak, R. (2024). The effectiveness of regulations preventing alcohol-related road traffic crashes and fatalities in the European Union countries. Journal of Safety Research, 88, 161–173.

Nistal-Nuño, B. (2017). Segmented regression analysis of interrupted time series data to assess outcomes of a South American road traffic alcohol policy change. Public Health, 150, 51–59.

Norstroem, T., & Laurell, H. (1997). Effects of the lowering of the legal BAC-limit in Sweden. In C. Mercier-Guyon (Ed.), Proceedings of the 14th International Conference on Alcohol, Drugs and Traffic Safety (pp. 87–94). Centre d'Etudes et de Recherches en Médecine du Trafic.

Portillo, J.E., Sugiarto, W., & Willardsen, K. (2024). Drink…then drive away: The effects of lowering the blood alcohol concentration in Utah. Health Economics, 33(8), 1869–1894.