I have always preferred the concept of “impaired” driving, rather than the traditional “drunken driving”, or “DWI”. Impaired driving is a much broader concept that better captures the real risks of sharing the road with others. For example, if we are on the lookout for the traditional drunk-driver, we may be more likely to let our guard down during daytime hours, expecting (rightly) that the drunks are probably more likely to be in an inebriated state in the late evening or weekend nights.

This creates a false sense of security. I would hazard that impaired drivers are a far greater day-to-day risk if we have a clear understanding of the many different types of impairment. For example there are two general types of impairment: Transient, and Embedded.

Transient impairments may vary in duration. One gets a very bad piece of news while driving and becomes emotionally overwhelmed and distracted.  This may last from several seconds to a few minutes. On the other hand, a new driver may be impaired by the lack of skill and experience, but this impairment will change over time, as they become more proficient. Other transient impairments may include prescription medications, dope, and booze. They are transient in that they do eventually wear off (although often too late to prevent tragic consequences). Cellphones, as well as other technologies (e.g. GPS units), carry their own distraction risks. I have a friend who routinely drives while exhausted; he has rolled and totaled a couple of cars, luckily never killing anyone.

Embedded impairments may include age (both very young and very old), gender (testosterone is probably the most dangerous street drug), personality, intellectual capacity, poor driver education, as well as medical and psychiatric conditions. My wife was once attacked with hedge-shears by our next door neighbor, a little old lady in her eighties. She claimed that my wife had dug up her flowers and stolen them, and that the “Virgin” had told her so. Her daughter came over to apologize a few days later, explaining that her Mom had apparently suffered a small stroke and had been delusional. Nevertheless, we would see her drive off in her car every day!

And impairments can act synergistically. I know an elderly person (not a great driver to begin with), who went for an eye-exam where the doctor put in those pupil dilating drops, and then proceeded to drive through a red light, blind as a bat, causing a very serious accident. And imagine how many testosterone-pumped young bucks are driving on a Saturday night with a few beers in their bloodstreams!

I’ll go out on a limb and guess that about a quarter of all people on the road at any given point in time have some form of serious driving impairment. It’s a sobering thought (pun intended), to realize that there are so many impaired people on the road, but one doesn’t have to look very far…..just drive a few blocks and you’ll see plenty.