I've given my BF blowjobs while he drove on a few occasions, mostly on the highway because that's usually the part of driving where he does the least thinking, so his brain isn't missed if it lingers elsewhere. It's hot as hell, & he can usually spare a hand from the wheel to feel me up (nipplegasms, y'all) or walk those fingers further south. The only hitch is that I get tired & my spine hurts before I can make him come (this wouldn't be a problem for those of you without spinal cord injuries) but it's a problem pleasantly solved by pulling over & riding him in the passenger seat until we're both screaming.
& yes, I've read "The World According to Garp" (everyone should). It's a work of fiction, & the "Road Head" in question is being performed in a parked car, when another car, unable to stop on the icy driveway, slams into the back of it. So the accident was caused by someone who was not getting his dick sucked, & the point just seems moot, as does the fear. (Also, remember the kids? That seems worse to me than losing a few inches.)