Commentary on NTSB Recommendation to lower the blood alcohol limit for driving from .08 to .05 in the United States Commentary on NTSB Recommendation to lower the blood alcohol limit for driving from .08 to .05 in the United States



  • The risk of being involved in a crash increases significantly at .05 BAC. The risk of being involved in a crash increases at each positive BAC level, but rises rapidly after a driver reaches or exceeds .05 BAC compared to drivers with no alcohol in their blood systems (Blomberg, Peck, Moskowitz, Burns, & Fiorentino, 2005).
  • Recent studies indicate that the relative risk of being killed in a single-vehicle crash for drivers with BACs of .05 to .079 is at least 7 times that of drivers at .00 BAC (no alcohol), and could be as much as 21 times that of drivers at .00 BAC, depending upon the age of the driver. These risks are significant (Voas, Torres, Romano, & Lacey, 2012).

CALVERTON, MD – Researchers at Pacific Institute for Research and Evaluation (PIRE) say that the recommendation by the National Transportation Safety Board (NTSB) today to lower the illegal blood alcohol concentration (BAC) limit for driving from .08 to .05 in states has a strong evidence-based foundation. Most industrialized nations have already enacted a .05 illegal BAC limit. A review of the literature by PIRE researchers examines the effects of various BACs on driving and crashes. The review reveals important reasons why a .05 illegal BAC limit is a sound strategy.

“There is clear, solid, scientific evidence that lowering the illegal BAC limit to .05 is a strategy that states should strongly consider” said James Fell, a PIRE researcher. He points to laboratory evidence showing that most subjects are significantly impaired at .05 BAC (Ferrara, Zancaner, & Georgetti, 1994; Moskowitz & Fiorentino, 2000; Moskowitz, Burns, Fiorentino, Smiley, & Zador, 2000). Drivers with .05 to .07 BACs are also much more likely to be involved in a fatal crash than drivers who haven’t been drinking (Voas, et al., 2012).  The review was co-authored with Robert Voas, Ph.D., a PIRE senior research scientist. The researchers’ rationale is described in the following paragraphs.

The driving performance of virtually all drivers is impaired at .05 BAC.  Laboratory and test track research shows that most drivers, even experienced drinkers who typically reach BACs of .15 or greater, are impaired at .05 BAC regarding critical driving tasks. There are significant reductions in performance in areas such as braking, steering, lane changing, judgment and divided attention at a .05 of BAC. Some studies report that inadequate or reduced or compromised performance decrements in some of these tasks are as high as 30% to 50% at .05 BAC (Ferrara, et al., 1994; Howat, Sleet, & Smith, 1991; Moskowitz & Fiorentino, 2000; Moskowitz, et al., 2000).

Lowering the illegal BAC limit to .05 is a proven effective countermeasure that has reduced alcohol-related traffic fatalities in other countries, most notably Australia.  Although studies in Europe and Australia each use a different methodology to evaluate these effects, the evidence is consistent and persuasive that fatal and injury crashes involving drinking drivers decrease on at least 5% to 8% and up to 18% after a country lowers their illegal BAC limit from .08 to .05 illegal BAC (Bartl & Esberger, 2000; Brooks & Zaal, 1992; Henstridge, Homel, & Mackay, 1995; Homel, 1994; Noordzij, 1994; Smith, 1988). If all states were to adopt the .05 illegal BAC limit, and it is enforced, an estimated 500-800 lives could be saved each year in the United States (Tippetts, Voas, Fell, & Nichols, 2005; Wagenaar, Maldonado-Molina, Ma, Tobler, & Komro, 2007).

Most other industrialized nations around the world have set illegal BAC limits at .05 BAC or lower. All states in Australia now have a .05 illegal BAC limit. France, Austria, Italy, Spain, and Germany lowered their limit to .05 illegal BAC; and Sweden, Norway, Japan, and Russia have set their limit at .02 illegal BAC (World Health Organization [WHO], 2013).

A reasonable standard to set is .05 illegal BAC.  A .05 illegal BAC is not typically reached with a couple of beers after work or with a glass of wine or two with dinner. It takes at least four drinks for an average 170-pound male to exceed .05 BAC in 2 hours on an empty stomach (three drinks for a 137-pound female). The illegal BAC level reached depends upon a person’s age, gender, and weight, as well as the food in their stomach and their metabolism rate (NHTSA, 2005). No matter how many drinks it takes to reach .05 BAC, people at this level are too impaired to drive safely.

The public supports levels below .08 BAC.  The National Highway Traffic Safety Administration (NHTSA) surveys show that most people would not drive after consuming two or three drinks in an hour and believe the limit should be no higher than the BAC level associated with that (Moulton, Peterson, Haddix, & Drew, 2010). That would be .05 BAC or lower for most drivers.

Further progress is needed to reduce alcohol-impaired driving in the United States. It has been 30 years since the first two states adopted a .08 illegal BAC limit (Utah and Oregon in 1983) and 13 years since federal legislation provided a strong incentive to adopt a .08 illegal BAC limit. Progress to reduce impaired driving has stalled over the past 15 years (see Figure 1). Lowering the illegal BAC limit from .08 to .05 will serve as a general deterrent to all those who drink and drive that the state is getting tougher on impaired driving and will not tolerate it. Such legislation typically reduces drinking drivers in fatal crashes at all BAC levels (BACs>.01; BACs>.05; BACs>.08; BACs>.15) (Brooks & Zaal, 1992; Hingson, Heeren, & Winter, 2000; Hingson, Heeren, & Winter, 1996; Tippetts, et al., 2005; Wagenaar, et al., 2007).  


Figure 1. Proportion of All Drivers Involved in Fatal Crashes Estimated to Have Been Legally Intoxicated
(BAC = .08 g/dL), 1982-2010 (-37%) (Source: NHTSA, FARS,


The World Medical Association, the American Medical Association, the British Medical Association, the European Commission, the European Transport Safety Council, the World Health Organization, the Canadian Medical Association, the Centre for Addiction and Mental Health and the Association for the Advancement of Automotive Medicine all have policies supporting a .05 blood alcohol concentration (BAC) or lower as the illegal limit per se for drivers aged 21 and older. At least 91 countries around the world have adopted a .05 illegal BAC or lower limit for driving while 54 countries use limits from .06 to .12 illegal BAC (WHO, 2013).

The evidence is clear—lowering the BAC limit to .05 has saved lives in other countries and can do so in the United States. It is time we learned from our European and global partners in achieving further declines in impaired driving fatalities (Transportation Research Board, 2010).

To arrange an interview with the PIRE Researchers, Dr. Voas or Mr. Fell, please contact PIRE Communications at or (888) 846-7473.




Bartl, G., & Esberger, R. (2000). Effects of lowering the legal BAC limit in Austria. In H. Laurell & F. Schlyter (Eds.), Proceedings of the 15th International Conference on Alcohol, Drugs and Traffic Safety - T'2000; May 22-26, 2000. Stockholm, Sweden: International Council on Alcohol, Drugs and Traffic Safety (ICADTS).

Blomberg, Richard D., Peck, Raymond C., Moskowitz, Herbert, Burns, Marcelline, & Fiorentino, Dary. (2005). Crash Risk of Alcohol Involved Driving: A Case-Control Study. Stamford, CT: Dunlap & Associates, Inc., from

Brooks, C., & Zaal, D. (1992). Effects of a 0.05 Alcohol Limit in the Australian Capital Territory. Canberra, Australia: Federal Office of Road Safety MR 10.

Ferrara, S.D., Zancaner, S., & Georgetti, R. (1994). Low blood alcohol levels and driving impairment. A review of experimental studies and international legislation. International Journal of Legal Medicine, 106(4), 169-177.

Henstridge, J., Homel, R., & Mackay, P. (1995). The long-term effects of random breath testing in Adelaide. In C.N. Kloeden & A.J. McLean (Eds.), Proceedings of the 13th International Conference on Alcohol, Drugs and Traffic Safety - T'95, Aug 13-18, 1995. Adelaide, Australia: International Council on Alcohol, Drugs and Traffic Safety (ICADTS).

Hingson, R., Heeren, T., & Winter, M. (1996). Lowering state legal blood alcohol limits to 0.08 percent:  The effect on fatal motor vehicle crashes. American Journal of Public Health, 86(9), 1297-1299.

Hingson, R., Heeren, T., & Winter, M. (2000). Effects of recent 0.08% legal blood alcohol limits on fatal crash involvement. Injury Prevention, 6(2), 109-114.

Homel, R. (1994). Drink-driving law enforcement and the legal blood alcohol limit in New South Wales. Accident Analysis and Prevention, 26(2), 147-155.

Howat, P., Sleet, D., & Smith, I. (1991). Alcohol and driving: Is the 0.05% blood alcohol concentration limit justified? Drug and Alcohol Review, 10, 151-166.

Moskowitz, H., Burns, M., Fiorentino, D., Smiley, A., & Zador, P. (2000). Driver characteristics and impairment at various BACs. (DOT HS 809 075). Washington, DC: U.S. Department of Transportation, National Highway Traffic Safety Administration.

Moskowitz, H., & Fiorentino, D. (2000). A review of the literature on the effects of low doses of alcohol on driving-related skills. (DOT HS 809 028). Washington, DC: U.S. Department of Transportation, National Highway Traffic Safety Administration.

Moulton, B.E., Peterson, A., Haddix, D., & Drew, L. (2010). National Survey of Drinking and Driving Attitudes and Behaviors: 2008 (Volume II: Findings Report). (DOT HS 811 343). Washington, DC: U.S. Department of Transportation, National Highway Traffic Safety Administration.

National Highway Traffic Safety Administration. (2005). The ABCs of BAC: A guide to estimating blood alcohol concentration and alcohol impairment. (DOT HS 809 844). Washington, DC: Department of Transportation.

National Highway Traffic Safety Administration. (2013). Fatality analysis reporting system data files, 1982-2010. U.S. Department of Transportation, National Highway Traffic Safety Administration: Washington, DC

Noordzij, P.C. (1994). Decline in drinking and driving in the Netherlands. Transportation Research Circular, 422, 44-49.

Smith, D.I. (1988). Effect on traffic safety of introducing a 0.05% blood alcohol level in Queensland, Australia. Medicine, Science and Law, 28(2), 165-170.

Tippetts, A.S., Voas, R.B., Fell, J.C., & Nichols, J.L. (2005). A meta-analysis of .08 BAC laws in 19 jurisdictions in the United States. Accident Analysis and Prevention, 37(1), 149-161.

Transportation Research Board. (2010). Achieving traffic safety goals in the United States: Lessons from other nations. Washington, DC: Transportation Research Board of the National Academies of Science, Committee for the Study of Traffic Safety Lessons from Benchmark Nations. (Special Report 300).

Voas, Robert B., Torres, Pedro, Romano, E., & Lacey, John H. (2012). Alcohol-related risk of driver fatalities: An update using 2007 data. Journal of Studies on Alcohol and Drugs, 73(3), 341-350.

Wagenaar, A., Maldonado-Molina, M., Ma, L., Tobler, A., & Komro, K. (2007). Effects of legal BAC limits on fatal crash involvement: Analyses of 28 states from 1976 through 2002. Journal of Safety Research, 38, 493-499.

World Health Organization. (2013). List of countries' BAC limits for driving. World Health Organization: Geneva, Switzerland. Retrieved May 9, 2013, from*;BACGROUP:*




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