The Drinking Ageand TrafficSafetyPeter Asch and David Levy

INRECENT YEARS there have been two revolu-tions in U.S. drinking age policy. During theearly 197os, 29 states lowered their mini-

mum legal drinking ages, usually from 21 to 18.Since 1975, almost all states have raised theirdrinking ages to 21. Today,just two states permitpeople under 21 to purchase alcoholic beveragesand these states suffer a reduction in federalhighway funds as a result. The minimum legaldrinking age is currently considered an impor-tant public policy tool for reducing alcohol-related traffic fatalities.

The rationale for raising the drinking age isboth familiar and widely accepted. Young driv-ers, especially males, have long accounted for adisproportionate number of traffic accidents andfatalities; and alcohol consumption is implicatedin a substantial proportion of serious and fatalcrashes. Thus, it would seem, limiting an alreadyrisk-prone group's access to alcohol can onlyhave salutary effects, and would reduce thetragic costs imposed on society by youngdrinking drivers.

There is some evidence that appears to sup-port this view. Although empirical estimates varyconsiderably, it is typically observed that when astate raises its legal drinking age-say from 18 to

Peter Asch is professor of economics at RutgersUniversity. David Levy is an economist at theFederal Trade Commission. The authors' views andconclusions do not necessarily reflect those of thecommission.

21-fatality and accident rates decline percepti-blyamong 18 to 2o-year-olds. A recent survey bythe U.S. General Accounting Office (1987), forexample, concludes that "raising the drinkingage has, on average, a direct effect in reducingalcohol-related fatalities among affected agegroups across states."

This is an interesting and important observa-tion. It does not, however, constitute persuasiveevidence that higher drinking ages make theroads safer. The reality is that higher drinkingages may simply be moving the problem around,rather than solving it.

Drinking Age and Drinking Experience

Proponents of the 21-year-old drinking age con-tend, often implicitly, that it is the combinationof age and alcohol that creates an abnormal driv-ing hazard. This, in effect, is a "drinking age"explanation of traffic risks: there is somethingpeculiarly dangerous about young drinking driv-ers. (Drinking and driving are, of course, inher-ently dangerous at any age.)

There is an alternative hypothesis that ap-pears equally plausible: inexperience in drinkingcreates a driving risk that is, at least partially,independent of age. Put most simply, this "drink-ing experience" hypothesis states that new drink-ers are dangerous drivers, whether they are 18,21, or (conceivably) 30. New drinkers maypresent abnormal risks either because there is

some sort of learning or tolerance curve associ-ated with alcohol consumption, or simply be-cause attainment of the legal drinking age is amajor life event that induces many initiates to"go overboard."

If the experience hypothesis is correct, driv-ers aged 18 to 20 may indeed enjoy lower acci-dent and fatality rates upon raising the drinkingage from 18 to 21, but there will be a "newdrinker" risk among 21-year-olds. Following anincrease in the drinking age from 18 to 21, wewould thus expect fatalities to decline amongthose aged 18 to 20, but (with the appropriatetime lags) to increase among 21 and perhaps 22-year-olds.

The experience hypothesis thus suggests thatan increase in the minimum legal drinking age islikely to shift the age distribution of fatalities-ineffect, "postpone" some fatalities from 18 to 21.It is unclear whether the higher drinking age onbalance saves lives. There is no theoretical or apriori basis for choosing between the age and

experience hypotheses; both might have somevalidity. The issue is purely empirical.

The fact that previous empirical studies havefailed to examine drinking experience suggeststhat their results may be biased in two ways.First, by focusing on only the directly-affectedage groups (18 to 20-year-olds, for example, in astate that raises its drinking age from 18 to 21),these studies ignore the experience of cohorts asthey attain the new, higher drinking age. This issomewhat akin to examining the benefits of apolicy without considering offsetting costs. Inaddition, by focusing on short-term effects, thesestudies ignore the fact that states that lower thedrinking age undergo a temporary bulge in thepopulation of inexperienced drinkers. By thesame token, states that raise the drinking age seea temporary decline in this high-risk group. Eval-uations that are confined to relatively short-termexperience following a change in the drinkingage may therefore exhibit safety patterns that areunlikely to persist over time.

We examined traffic fatality rates in 47 statesover a 10-year period, 1975 to 1984, duringwhich drinking ages were on the rise. Four co-horts-ages 18, 19, 20, and 21-were scrutinized(for a total sample size of 1,880). Fatality rateswere compared for cohorts who could and couldnot drink legally in particular states and years(drinking was illegal in 571 of the 1,880 cases).

Some suggestive statistics on the relation-ship between legal drinking status and fatalitiesare presented in the accompanying table.

Panel A displays total driver fatalities, and PanelB displays single-vehicle nighttime driver fatali-ties. The fatality rates displayed are numbers offatalities among 18, 19,20, and 21-year-olds per100,000 licensed drivers in each age group. Theyare computed as simple averages of fatalitiesacross different states; weighting by state driver-population size would yield similar patterns. Thetop two rows of each panel compare fatality ratesfor cohorts who could and could not drink le-gally; the bottom two rows, which are limited tocohorts who could drink legally, compare fatal-ity rates for those in their first year of legal

AVERAGE ANNUAL TRAFFIC FATALITIES PER 100,000 DRIVERS(Cohorts of Various Ages During 1975·1984)

First Year of LegalDrinking

First Year of LegalDrinking

Panel AALL ACCIDENTS

45 42 39 42

44 45 42 40 42

44 55 46 39 45

41 42 40 41

Panel BSINGLE-VEHICLE NIGHTTIME ACCIDENTS

17 15 13 15

14 16 15 14 15

14 23 22 12 15

13 15 15 14

drinking status (cohort age is equal to drinkingage) and those in their second through fourthyears of legal drinking status.

No strong impact of higher drinking ages isreadily apparent. Considering the data in the toptwo rows of each panel, the mean fatality rates

The effect of drinking age alone on traf-fic fatality rates appears inconsistent andfrequently minor, whereas the effect ofdrinking experience is consistent, usuallysignificant, and frequently quite strong.

for cohorts who could and could not drinklegally over the period are virtually indistin-guishable, and the differences are not statisti-cally significant. The age 19 cohort, for example,has an overall fatality rate of 45 per 100,000 driv-ers when drinking is legal as compared to 42 per100,000 drivers when it is not; the rates for sin-gle-vehicle nighttime accidents among the age19 cohorts are 16 per 100,000 and 15 per100,000, respectively. These differences in fatal-ity rates are not statistically significant. The oneexception is the fatality rate for single-vehiclenighttime accidents among 20-year-old drivers,which is significantly higher when drinking islegal than when it is not. For 18-year-olds, drink-ing cohorts have lower fatality rates than non-drinking cohorts. There is, however, a complica-tion in interpreting the data on 18-year-olds.Since no state has permitted drinking at agesyounger than 18, all 18-year-olds who can drinkare also in their first year of legal drinking ex-perIence. Legal drinking and inexperienceddrinking at age 18 are thus perfectly correlated,and it is not possible to separate the two effectson fatalities for this cohort.

Turning now to the data in the bottom tworows of each panel, which are disaggregated onthe basis of drinking experience, it can be seenthat drivers in their first year of drinking experi-ence are at high risk for fatalities. (This is not thecase for 18-year-olds; recall, however, it is impos-sible to separate the effects of drinking age anddrinking experience among 18-year-olds). For19-year-olds, fatality rates (both total driver andsingle-vehicle nighttime) jump sharply in thefirst year of legal drinking and decline in the sec-ond year. Considering single-vehicle nighttimeaccidents, for example, the fatality rate among

19-year-olds in their first year of legal drinking is53 percent higher than among 19-year-olds whocould not drink legally (23 compared to 15); it is77 percent higher than among 19-year-olds intheir second, third, or fourth year of legal drink-ing status (23 compared to 13). The pattern isrepeated among 20-year-olds. A further disaggre-gation of these data suggests that the increasedfatality risk for 20-year-olds lasts for the first twoyears of legal drinking, and declines sharply inthe third year. The higher fatality rates for firstyear drinkers are statistically significant.

Among 21-year-olds, the patterns differ. Con-trary to what we expected, experienced drinkershave a higher fatality rate than first year drink-ers. This pattern, however, is not statisticallysignificant.

The evidence we have presented, while notdefinitive, provides support for the drinkingexperience hypothesis: new drinkers appear tobe relatively risky drivers. Further, the new-drinker risk appears to erode quickly-after oneor two years. In contrast, simple fatality ratecomparisons do not suggest with much strengthor consistency that legal drinking status exertsmuch influence.

Legal drinking age does not appear to bean important weapon in the public trafficsafety arsenal.

The simple comparisons that we have pre-sented are suggestive rather than conclusive. Wehave subjected the data to more demanding sta-tistical analyses, and have reached similar con-clusions. The effect of drinking age alone on traf-fic fatality rates appears inconsistent andfrequently minor, whereas the effect of drinkingexperience is consistent, usually significant, andfrequently quite strong.

Policy Suggestions

On the basis of the evidence, we conclude thatlegal drinking age does not appear to be animportant weapon in the public traffic safety ar-senal. We cannot rule out the possibility thatraising the drinking age saves lives, but such aneffect is not obvious in the fatality patterns weobserve. The hazards posed by new drinkers,

regardless of age, appear considerably stronger.It is likely that advocates of a higher drinking agehave attributed to young drinkers the risks thataccompany new drinking at various ages.

The consciousness.ralsmg efforts ofgroups such as Mothers Against DrunkDriving have probably had a greaterimpact on alcohol·related crashes thanlaws that have increased drinking ages.

It does not necessarily follow that the 21-year-old drinking age is a "bad" idea. It might yetbe judged desirable on balance. It should be rec-ognized, however, that the major benefit claimedfor this policy has been seriously exaggerated. Inthe short term, we believe that alternative poli-cies, including educational efforts and vigorousenforcement of existing drunken-driving laws,are more promising. Indeed, the consciousness-raising efforts of groups such as Mothers AgainstDrunk Driving have probably had a greater im-pact on alcohol-related crashes than laws thathave increased drinking ages.

A true long-term solution to the problem ofdrinking drivers is likely to require either a basicchange in the way alcohol is introduced to theyoung, such as explicit approval of "responsible"drinking at relatively young ages, as in France, orstronger measures to discourage drunken driv-ing. Some Scandinavian nations, for example,routinely imprison those caught drinking anddriving, and regard as unacceptable any alcoholconsumption by drivers. Whatever the decision,it seems clear that the means by which we nowmake alcoholic beverages available to theyoung-proscribing consumption up to an arbi-trarily specified age, and allowing it from thatmoment on-is a policy of little use in pro-moting highway safety. _

Selected ReadingsAsch, Peter, and David Levy. The Minimum Legal

Drinking Age and Traffic Fatalities, Report to theNational Institute on Alcohol Abuse and Alco-holism, Grant No. ALCP 1 ROI AA06856-1(November 1986).

U.S. General Accounting Office. Drinking Age Laws:An Evaluation Synthesis of Their Impact on High-way Safety, GAO/PEMD-87-10 (March 1987).