Colin McCallin Aug. 8, 2017

Utah recently passed a bill to lower the per se limit for DUI from .08, the national standard, to .05. The state argued that numerous studies indicate this would increase safety. However, the American Beverage Institute countered with an ad that stated driving at a .05 makes you no more impaired than driving while over 65 years of age. The ad outraged some people, in particular the legislators who voted for the measure and are also over 65, whose images were used in the advert. But is any of this true and will lowering the DUI limit make a significant difference or just get more people in trouble for the wrong reasons?

What Per Se Limits Mean

The per se DUI limit indicates that a person is impaired after they have consumed a certain amount of alcohol in a certain period of time. In other words, there is no debate about whether you felt sober, acted sober, or drove sober. The law says you were drunk if you test at this limit or higher, regardless of any outward indications of impairment, or lack thereof. While alcohol metabolism varies by weight and circumstance, most people safely process about a drink per hour, any more and there may be significant intoxication. Five drinks over about 2 hours for a 160 pound person who hasn’t eaten much, for example, would put that person at a .08 or .09. Frankly, this sounds about right to most people. However, when the limit is lowered to .05 you can see that this would mean about 2-3 drinks over the same amount of time, perhaps with food, which many individuals would not perceive as impaired. This less intuitive limit may lead more people to get in trouble when they were not impaired enough to affect their driving.

In fact, this is in part why Colorado has a DWAI law, which indicates mild impairment at .05 to .079. There is some risk but the law recognizes it is less and so the consequences are not as severe.

Why .05?

The National Transportation Safety Board (NTSB) has long recommended lowering the per se limit because studies show significant impairment starting at this level, and reduced crashes when this limit is enforced. In Australia, lowering the limit to .05 reduced fatal crashes in Queensland by 18% and by 8% in New South Wales. Their efforts also indicate that strong interventions, like zero-BAC interlocks for offenders, and treatment, reduce recidivism and are estimated to save over a one thousand lives per year. The evidence of reduced fatal crashes after a reduction in DUI limits, along with the known increase in crash risk and the known impairment at these levels compels the NTSB to recommend a .05 limit.

While this is strong evidence, there are other factors besides alcohol that increase a driver’s chance of being in an accident.

Other Driving Impairments

We recently wrote about how distracted driving and texting can increase your crash risk significantly more than alcohol. So it comes as no surprise, besides their vested interest, that the American Beverage Institute is making the claim that driving while old is as bad as driving while at a .05. There are numerous things that can create impairment while driving that are next to impossible to legislate.

Here are some numbers for crash risk:

Drinking at .08, the Federal standard, increases crash risk by 2.69 times

While over 65 years old: 2.59 times

While at a .05: 2.03 times

While texting: 23 times

Driving with less than 6 hours sleep: 2 times

Driving with less than 4 hours sleep:11 times

Being a teenage driver with teen passengers or a teenager driving at night: 4 times increased crash risk

Other risk factors for crashes include things like being male or driving in the rain, and even types of personality, as in whether you are calm or quick to anger or just having a bad emotional moment.

These examples reveal a truth that may be hard to accept, a great deal of driving carries risks and the law may not be able to prevent all these risks. Moreover, of the known driving risks, driving at a .05 is not as significant as other ordinary things, like being old or very tired.

The Utah law is slated to go into effect at the end of 2018, but it still faces opposition and many do not rule out that it may be amended or repealed. In the meantime, Utah is on track to have the toughest drunk driving laws in the country.