Here in the capital, there is a whole new etiquette at stoplights.

Upon arriving at a red light, drivers apply the brakes, pick up their mobile devices, and begin reading and sending e-mails. The signal to resume driving comes not from the green light but from some motorist in the back tapping politely on the horn.

It is not uncommon to drive up to a light and discover several vehicles still immobile because no one has yet noticed the green. A horn tap will cause the procession slowly to restart, as drivers, one hand on the wheel and one holding their devices, type a few last words. Or sentences.

So you can imagine my surprise Wednesday when I was driving down Connecticut Avenue, scanning the Twitter feed on my iPhone, and came across this bulletin: “NTSB calls for a nationwide ban on driver use of personal electronic devices.”

I spit my coffee onto my laptop and nearly cut myself with the electric razor I had been using. I lowered the volume of MSNBC on my satellite radio so that I could focus on the important task at hand: Surfing the Web on my phone to learn just what the folks at the National Transportation Safety Board were thinking.

Turns out they weren’t thinking very much. They were proposing to “ban the nonemergency use of portable electronic devices” – including hands-free mobile phones – “for all drivers.” It’s an absurd overreaction to an unrelated problem.

The accident that spurred the proposal was a grisly 2010 crash in Missouri caused by a driver who was texting – which is definitely a bad thing to do behind the wheel – and not talking – which is not nearly such a bad thing. To conclude that the answer is to ban all cellphone conversations is a government overreach far more invasive than the supposed death-panels of the health-care law. The agency’s proposal, if embraced by lawmakers and the administration, would jeopardize Transportation Secretary Ray LaHood’s noble effort to crack down on distracted driving.

I’ve never had a distracted-driving related accident, but that is probably a matter of luck. I’ve downloaded iTunes while driving, made reservations on OpenTable, and done part of a Washington Post Web chat. Driving in New Hampshire recently, I found myself playing a conference call on speakerphone and recording it with my digital recorder while changing the destination on my GPS.

Clearly, I need to break this addiction, but the ban on texting – already in effect – is not having much effect. Often, I’ll look up to see if the cop stopped next to me at the light can see my lawbreaking, but invariably he’s staring at his own device. The likelier solution is what’s already happening: awareness campaigns to teach about the dangers of texting behind the wheel and the spread of technologies in cars to make hands-free conversations easier.

The NTSB could encourage both of those solutions, but instead it went in the other direction. Writing in Friday’s Post, NTSB Chairman Deborah Hersman claimed: “Studies published in 2008 in the journal Brain Research as well as in the Journal of Experimental Psychology show that it is more distracting to engage in a cellphone conversation than it is to talk with a passenger.”

Incredibly, the NTSB has no data to support its radical proposal – only some laboratory-based studies, and those are inconclusive. The “Brain Research” study speculates that cellphone conversations are more distracting that “listening to a radio, eating and drinking, monitoring children or pets, or even conversing with a passenger,” but the authors admit: “It is not known exactly how much each of these distractions affects driving.”

The other study concludes that, while cellphone conversations can be more dangerous than those with a passenger, a passenger who is “constantly commenting and directing attention in an overcontrolling fashion has a potentially negative impact on performance.”

So, to be evenhanded, the NTSB should also propose a ban on back-seat driving, a ban on transporting children, a ban on radios and cup holders, and a ban on GPS devices, so that we can go back to those safer times when we blocked the windshield with gas-station maps. The agency should also ban cellphone use by pedestrians, to keep them from wandering into intersections.

An absolute ban would be the equivalent of defining a drunk driver as any motorist with a blood-alcohol content above 0.00. This would turn us into a nation of lawbreakers and erase the distinction between what is truly dangerous and what is relatively safe.

Disagree? Send a tweet using the hashtag #cellphoneban. I’m going out for a drive.