I was in New York for work this week and mostly relied on taxis to get around.
I got into one cab, and the driver asked if it was okay if he talked. What a polite gentleman, I thought. "Of course, we can talk!" I said.
It turns out he meant he wanted to talk on his cell phone to someone else. He asked my permission because cabbies in New York aren't allowed to talk on cell phones while they drive — even with a hands-free headset. So it was basically him saying, "Are you going to object if I break the law and possibly put your life in danger?"
I said it was fine by me, though it would be safer if he used a headset instead of putting his phone to his ear. But he said that anytime police see a cab driver with a headset, they automatically cite the person. And it's a hefty fine.
The result is drivers are more likely to NOT use a headset because they don't want evidence that they're using a phone. If they just hold their phone to their ear, it's easier to drop the phone and pretend they weren't talking.
The lesson? This is what happens when you have total prohibitions: People ignore the law and end up doing things that are even more dangerous.