Q: I’m wondering how other states compare to Washington regarding how much alcohol you’re allowed to consume and still drive. Isn’t there a state or two that has zero tolerance? I know some countries also have zero tolerance. I wonder if the law allowing up to .08 BAC or 5 ng/mL for cannabis gives people the idea that driving with some substances is okay, or that we are “safe” within those limits. Why isn’t Washington’s BAC limit lower?
A: Your question brings up a misperception that I see repeatedly; the idea that it’s okay to drive as long as your Blood Alcohol Level (BAC) is lower than .08. I’ll get to the comparisons you asked about in a moment, but if there’s one thing I want people to take away from reading this, it’s that you can be impaired (and get arrested for impaired driving) well below the per se limit of .08.
Impairment isn’t a fixed line. It’s not like you’re safe to drive at .07 and drunk at .08. Studies consistently show that even at a BAC of .02 your driving can be affected. Yes, our law has some hard numbers for alcohol and cannabis, but I think some people misunderstand what they mean. It’s not that you’re legally good to drive below those levels. I often hear .08 referred to as the “legal limit,” which could imply that it’s legal to drive below it. However, it’s actually a per se limit, which means that the .08 BAC itself is confirmation of impairment without any further evidence. That’s almost the opposite of how some people understand it.
In addition to the numbers, the law states that a person is guilty of DUI if they drive while “under the influence or affected by” alcohol or other drugs. If a driver is affected by an impairing substance, that’s DUI, regardless of the percentage of substance in their system. If a driver gets arrested for DUI and blows .05, the driver doesn’t get off of the charge. The court will rely on all the other evidence of impairment collected by the investigating officer to reach a conviction.
In that sense, Washington kind of is a zero tolerance state, in that the law has zero tolerance for impairment. But I understand you’re asking about zero tolerance in per se limits. There are no zero tolerance states in the US. Utah was the first (and currently only) state to pass a .05 limit, which went into effect in 2018. Other states, including Washington, have proposed similar bills, but so far have not moved from bill to law.
Globally, the majority of countries have a limit of .05, some have limits lower than that, and a few countries have true zero tolerance laws. Lower limits make sense based on the science around impairment. At a BAC of .02 alcohol begins to affect visual acuity and the ability to perform two tasks at the same time. By .05 it reduces coordination, diminishes ability to track moving objects and delays response to emergency driving situations. All this happens below the level of our current per se limit in Washington.
Despite only a few people driving impaired, over half of all traffic fatalities in Washington involve impairment. Lowering the per se limit to .05 is a proven strategy for reducing impaired driving fatalities, and as a bonus, most Americans are in support of it. Given that both science and public support align on lower per se limits, I wouldn’t be too surprised to see it change in Washington in the near future.