Moving at a stately 30 miles an hour, the woman drove her tank-like vehicle right through the stop sign and almost through me as I crossed the street. Like the psychiatrist assigning mental illness at the mere sound of crazy shouting, I didn’t have to look at the motorist. I just knew from her behavior that she was yakking on a cellphone. Sure enough, she was.

Many of us who play pedestrian — even if only in parking lots — have dodged motorists blankly staring out the windshield as they jabber on the phone. Between now and the ringing-in of 2012, countless families will have suffered tragedy at the hands of these distracted drivers. And nothing will have been done about their dangerous practice, given the strong political and societal forces amassing in its defense.

But a serious discussion will have begun. For that, we can thank the brave bureaucrats at the National Transportation Safety Board. NTSB Chair Deborah Hersman recently called on states to ban driving under the influence of a phone call. She means all cellphone use, including that with wireless headsets. The hazard of phoning and driving isn’t about where the hands are. It’s where the brain is. (I’ve seen guys engrossed in conversation stop their cars in the middle of the road.) Whether one holds the phone in a hand, wears a headset or talks into a car’s voice-activated system, it is the conversation itself that threatens the public.

I would guess that the driver cited above is a hardworking mother. Like many Americans, especially women, her hours rush by in perpetual-motion activity. She feels she must work for pay, bake cookies, chauffeur kids, drop off dry cleaning, shop for presents, get her nails done, do laundry, decorate the house. She is all things to all people, except for those who share the road with her. The bicyclist who assumes she’s going to stop at the stop sign is virtually invisible to her.

Apparently, there is no such thing as true multitasking. What we call multitasking is actually moving rapidly among different actions. We do one thing, then we do another. The student working on homework while watching TV isn’t accomplishing both at the same moment. His attention may flit back and forth, but at any time, it is on one of the two activities. (So the idea that young brains are better at multitasking is off base. Young people are said to be better at rapidly switching back and forth between tasks than their elders.)

Over the years, our car-dominated society has taken only baby steps toward reining in the use of distracting technology on the road. No one knows this better than California Sen. Joe Simitian, a Democrat who spent five years getting his state to ban hand-held cellphone use. Eight other states have followed suit. But no state has said “no phoning while driving, period,” as the NTSB urged this month.

Such change won’t happen quickly. Multitudes of time-stressed Americans demand the freedom to phone under any circumstances. Thus, lawmakers who rage over the less-disabling effects of moderate drinking on driving ability defend this practice as some inalienable right. (Only 35 states have even outlawed texting while driving.) The powerful mobile-phone industry would go bonkers at the thought of a complete ban. And the car manufacturers who put in voice-activated systems as a supposed safety feature would (understandably) respond, “Hey, wait a minute.”

Like the campaign against drunk driving, this one will take time — and with it, a rising tally of innocent victims. Someday, it is hoped, bans on driving while phoning will become the law of the land. Kudos to the NTSB for starting the journey.

Froma Harrop is a columnist for The Providence Journal.