Tuesday, May 24, 2011

Cell Phones versus Drunk Driving

Most of you are familiar with the research that using a cell phone is just as dangerous as driving drunk.
Method: We used a high-fidelity driving simulator to compare the performance of cell phone drivers with drivers who were intoxicated from ethanol (i.e., blood alcohol concentration at 0.08% weight/volume). Results: When drivers were conversing on either a handheld or hands-free cell phone, their braking reactions were delayed and they were involved in more traffic accidents than when they were not conversing on a cell phone. By contrast, when drivers were intoxicated from ethanol they exhibited a more aggressive driving style, following closer to the vehicle immediately in front of them and applying more force while braking. Conclusion: When driving conditions and time on task were controlled for, the impairments associated with using a cell phone while driving can be as profound as those associated with driving while drunk
That and similar research has led to bans on hand-held (though usually not hands-free) cell phone use in many locations. Statistics are hard to come by but there are more alcohol-related accidents and many more alcohol-related deaths than those due to cell phones. Yet there are far more people talking on cell phones than driving drunk. This contradiction bugged me. What's going on?

Unlike using a cell phone, drunk driving is not a binary event. It's not that you are either drunk or you aren't. There are degrees based on the blood alcohol level. The real dangerous drivers are those way over the legal limit. Driving at the legal limit (0.08% in Illinois) isn't that dangerous or the limit would be lower.

When we hear that using cell phones are just as dangerous as driving drunk, we think, wow, cell phones are very dangerous. But our thoughts of the dangers of drunk driving is not at the level of drunkedness that are compared to cell phones.

Driving at the legal limit and on your cell phone are only mildly more dangerous than driving sober and distraction free. I'm not recommending that you drink or use your cell phones while you drive, you are certainly safer without doing so. But you should also be careful about reports about the dangers of activities and be sure the comparisons are correct. 


  1. America has a long tradition of drinking alcohol being viewed as sinful. Conversely, talking on a cell phone is viewed as businesslike and hence virtuous. So it is easier to condemn people for drinking alcohol while driving vs talking on a cell phone.

  2. Lance asserts: "There are far more people talking on cell phones than driving drunk."

    At any given instant of time, perhaps the two numbers are comparable ...

    It is reasonable for cyclists and pedestrians to fear them equally.

  3. http://www.nhtsa.gov/people/injury/research/809-050pdf.pdf

    If you look at the chart on page 13, you'll see that someone at the legal limit in the US is at least 5 times more likely to have an accident. The figures are indeed even worse as BAC gets higher, but 5x is a huge increase compared to sober.

    So yes, if you compare a cellphone user to someone who is completely off their face, the cellphone user looks better. But if you compare a cellphone user to a sober person, their driving is objectively terrible.

  4. Why don't we just make it illegal to be distracted while driving and be done with it.

  5. Using a cell phone is not a binary event either. Nor is driving. Unlike being drunk, you can choose when to use your cellphone and perhaps only talk for a short time in the safest, most predictable portion of your trip---hanging up or transferring your attention if you see something arise. If you are drunk, you'll be drunk the whole way home, with no way of modulating it.

    I would guess that driving on an uncongested freeway with a cell phone is safer than doing so while intoxicated---because other skills besides braking reactions gain importance on a freeway.

  6. Who got jobs where?

  7. Every time I see that a car moves from one lane to another without paying any attention to the surrounding traffic, it turns out that the driver talks on the phone. But unfortunately cell phone laws are not enforced in the US.

  8. 5X increase in accidents may or may not be a lot. You're risk of an accident driving a short distance is not so much to begin with. I think the underreported statistic is how dangerous driving is period.

    This stat would seem to imply that a 3,000 mile cross country road trip is 600 times more dangerous than driving one mile home at epsilon beneath the legal limit--and more so if you use your cell phone while you're driving cross country. Or that getting a ride from a completely sober friend is actually more dangerous if you have to go out of the way a little to drop other poeple off.

    In the end, (as Lance points out) it is pretty hard to meaninfully compare these statistics. But as others point out, it is pretty easy to interpret them for personal use: don't drive, if you do, don't use your cell phone or be drunk. And of course, do a lot of complexity theory :)

  9. I think there is more attention given to cell phones then drinking just because its a newer thing. And since its newer, the laws are still being worked out on it. (As opposed to drunk driving which is illegal in all US States.)

  10. Personally, I have at least twice been almost hit by people talking on cellphones: once on a 4 way stop, the cellphone talker just stopped, did not look and drove in; once an suv on a freeway changed lanes into me forcing me into the shoulder. Personally, even talking on a bluetooth headset while driving, I have found myself distrcated. I therefore am skeptical of the accuracy of these experiments.

  11. While we are on the topic, putting a knife into a toaster is also much less dangerous than people make it out to be, using a hair dryer in the bath tub is an almost non-issue, and there is no reason to look both ways before crossing the street: drivers have a huge incentive to avoid accidents, and are already looking!

  12. I've heard Ron Graham say the Mark Braverman (from twitter feed) quote verbatim. Don't know if it is due to Graham or to someone else.

  13. I totally agree the amount of people i see texting or chating on there cell phones far out weights drink driveing...

  14. how is talking on a cell phone any different than conversing with another passenger. Should we ban more than 1 person in a car? We dont need any special laws governing this.

  15. This comparison makes me really annoyed because it puts the pretense of scientific objectivity on what is really a moral judgement.

    Lots of things make you a more dangerous driver. Being old, breaking up with your s.o., arguing with your s.o. in the car, having a baby in the car, working the night shift. I bet many if not all of these cause just as much distraction but since we don't view the underlying behavior as morally questionable we don't attempt to ban it.

    That's a fair and reasonable judgement for society to make. Even if driving a crying baby around is more risky it's reasonable to judge that there is more social gain in allowing mothers to take their infants around than in letting people talk on phones. However, people should stop hiding the fact that it's a flat out moral judgement about the benefits to society to letting people talk on cell phones.

    Frankly I am skeptical of how well these studies apply to the real world since in the real world people moderate their cell phone use by the driving conditions. For instance when I'm driving for hours on the interstate I happily chat on the cell phone as it helps keep me alert and will also do so in stop and go traffic where the risk of anything but a scrapped bumper is miniscule but will get off the phone when I enter city traffic.


    Ultimately the reason so many more people talk on cell phones is that we don't disapprove of it as much as we do drunk driving. I think most people want to be able to call up for directions when lost and chat when it keeps them awake on the highway (if they drive long stretches) but they are irked at the businessman who is so occupied by his phone he doesn't see the light change.

    I mean heck just consider the fact that no one is moving to ban CB radios for truckers which are strictly more complicated to operate.

  16. Also studies show that being stoned decreases your risk of causing serious accidents (your slower driving more than compensates your imparment) but we don't insist that people get stoned before driving either.

    It's just not about the risk it's about the moral judgement.

  17. Studies have shown the driving while talking decreases your reaction time about the same as driving while intoxicated. This study is accurate on that point. Any distraction that can take you away for a few seconds and reduce your reaction time is enough to cause a serious accident and maybe even death.
    I work for an organisation that educates people on the dangers. The distracted driving laws that are coming out are related to texting usually and that reduces your reaction time even more.

    TruePath, you need a little reality check. Being high on pot does not make you a better driver and "decreases your risk of causing serious accidents". Things on the road happen very quickly. Just because you are following slower behind someone doesn't mean a kid cant jump in front of your car only a few feet from you. Any impairment, whether it is being tired, being distracted, or being under the influence of alcohol or drugs impairs your ability drive enough to cause injury or death to you or others.
    Where I live it isn't the accidents in the city that are major problems with cellphone use. It is the accidents on big highways and rural roads where someone veers into another lane going very fast and it is all over.

    I agree that some news reports exaggerate, but the research has been done and it is dangerous.

  18. Liz-CoolProducts11:23 AM, June 15, 2011

    This is a very interesting debate, thanks for posting this!

    Why is that more people are killed from drunk driving then cell phones if cell phones are more dangerous?

    Does anyone have those exact stats?

    Does anyone know if accidents have decreased in states where cell phones have been banned?