The Role of Drunk Driving in Oklahoma’s Traffic Fatality Rate

SERIES: WHY IS OKLA’S TRAFFIC FATALITY RATE SO HIGH? (PART 2)

In a blog post yesterday, first of a series, I asked the question: Why is the Oklahoma traffic fatality rate almost twice the national average?

According to the National Highway Traffic Safety Administration (2012 data), one in every 5,405 Oklahomans will lose one’s life in an auto, truck, motorcycle, bicycle or pedestrian accident this year. At the national level, the rate is one in every 9,346 citizens. In other words:

A person living or passing through Oklahoma is almost twice as likely to die on an Oklahoma highway or road than the national average. Why?

When discussing traffic fatalities and how to avoid them, one of the most important factors to be considered is drunk driving. According to the NHTSA report (“Traffic Safety Facts Oklahoma: 2008-2012”), about one-third of Oklahoma traffic fatalities involve a driver who has a blood alcohol level above the legal limit. Here are the statistics for the past five years (2013 data not yet available):

Alcohol-impaired Driving Fatalities in Oklahoma (BAC: .08%+)

Fatalities in which at least one person involved in the incident had a BAC (blood-alcohol concentration) of .08% or above (the legal limit for drivers in Oklahoma).

Total traffic fatalities in Oklahoma

Alcohol-impaired fatalities: Broader Definition

Alcohol-impaired fatalities: Narrower Definition

Narrower Definition / Total fatalities

2008

750

260

242

32%

2009

737

236

229

31%

2010

668

235

222

33%

2011

696

235

222

32%

2012

708

230

205

29%

Statistics Are Easily Misinterpreted

One thing the above chart reveals is how easily statistics can become misleading if the person interpreting the data is not extremely careful.  For example:

• Based on the percentages in the right column, one might report: “The rate of drunk-driving fatalities increased slightly from 2009 to 2010, but declined slightly from 2010 to 2011.” That would be technically accurate, since the rate in those years went up from 31% to 33% and back down to 32%.

However, that statement would certainly be misleading. In reality, the actual number of drunk-driving fatalities went down from 2009 to 2010 and stayed the same from 2010 to 2011. The real change was in the number of total fatalities (the denominator in the percentages).

• Here’s another example of how easily these stats can be misleading. One column above is labeled “Broader Definition” (the NHTSA calls it the “Old definition”). Those numbers include every fatality in which a driver, motorcycle rider, bicyclist or pedestrian had a BAC of .08% or above. The “New” narrower definition does not include bicyclists and pedestrians. And that makes sense. When we are talking about drunk driving, it only skews the data to include bicyclists and pedestrians.

Under the “old definition,” someone could say: “More than one-third of traffic fatalities in the last 5 years involved alcohol impairment.”

Under the “new definition,” it becomes more accurate to say: “Less than one-third of traffic fatalities involve alcohol-impaired drivers.”

The reality didn’t change at all, just how we define the terms.

Lessons for Oklahoma about Drunk Driving

OK. That’s enough math for today. What can we learn about Oklahoma’s high traffic fatality rate from these statistics about alcohol-impaired drivers? Here are some observations.

1.  Drunk driving is certainly an important factor. As we have observed, about one-third of Oklahoma traffic fatalities involve a driver with a BAC above the legal limit.

2.  However, drunk driving is not the explanation of why Oklahoma’s fatality rate is so much higher than the national average. The NHTSA report also provides the national numbers, and you will see that the national ratio of drunk driving fatalities to total fatalities is almost exactly the same as the state ratio, from 30% to 32%.

3. Although drunk driving is clearly an important factor, it is not the only factor. The flip side of the observation above is that two-thirds of traffic fatalities do not involve drivers with illegal levels of alcohol in their system. If our goal is to reduce fatalities, we should be sure that we are considering all strategies, not just those that involve drunk drivers.

Some advocates would argue that the legal BAC limit is too high and that these numbers therefore do not reflect the full extent of the drunk driving problem. I wrote last year about a federal agency that recommends lowering the legal blood-alcohol limit to 0.05%.

How many more Oklahoma traffic fatalities would be categorized as “alcohol-impaired” if we lower the maximum BAC all the way to .01%? The NHTSA has some data on that. Unfortunately, the data is available only under the “old,” broader definition, so that’s what this chart shows:

Alcohol-impaired Driving Fatalities in Oklahoma (BAC: .08%+ and .01%+)

• Fatalities in which at least one person involved had a BAC above the indicated level.

• Statistics use NHTSA’s “broader definition” of alcohol-impaired fatalities, which includes bicyclists and pedestrians.

Total traffic fatalities in Oklahoma

Alcohol-impaired fatality: BAC = .08%+

Alcohol-impaired fatality: BAC = .01%+

2008

750

260

289

2009

737

236

268

2010

668

235

263

2011

696

235

265

2012

708

230

265

Lowering the threshold all the way down to .01% moves another 30 to 35 fatalities each year to the “alcohol-impaired” category. I would never discount the importance of even a single fatality. But these stats show:

• 87% to 90% of drivers with any measurable level of alcohol in their system have a BAC above the legal limit.

• Drivers with BACs above the legal limit are doing so despite it being illegal. If alcohol-impaired drivers are willing to climb behind the wheel in violation of the law, is there any basis for hoping that toughening the law will reduce the number of alcohol-impaired drivers?

• The vast majority of drivers with BAC levels below the legal limit are not causing traffic incidents that result in fatalities. There are less than three dozen such fatalities across the entire state each year.

I am not defending anyone who climbs behind the wheel with any amount of alcohol in one’s system. But we should make sure that our energies and funding are directed to the measures which will have the biggest impact on reducing traffic fatalities and other harms and losses that result from vehicle accidents.

Have you or a loved one experienced injury, loss of income or loss of life due to an auto, truck or motorcycle accident? Did the accident involve drunk driving, driving under the influence, driving while impaired by drugs or speeding? If so, you need experienced legal representation. Contact Hasbrook & Hasbrook immediately for a free consultation.

For more information, see our webpage: “DUI, drunk driving and speeding accidents.”