My mom is not much of a honker. You know what I mean when I say that: If a driver in front of her fails to hit the gas when the light turns, she simply waits. Time passes, and the green light glows. Eventually, the driver notices the signal change, or the cars behind begin to lay on their horns. Traffic proceeds. But no thanks to my mom; she's just not much of a honker.
For years I've been telling my mom that she ought to learn to honk a little more.
Then he goes on and on about how the horn isn't really a safety device. He talks about studies that show that honking is linked to aggression and gender, and that in most accidents, when it is used, it's too late.
Well, no crap. I've never viewed the horn primarily as a safety device. It's a crude communication device. Sometimes it's useful in exactly the situation the author talks about with his mother. If someone is not aware that a light has changed, beeping at them is fine. Other times it's useful to express dissatisfaction, e.g. when someone does something dangerous or rude on the roadway.
The only time it really works as a safety device is at speeds less than 10 mph, such as in a parking lot. Someone is pulling out of a spot and they don't see you. A beep let's them know you're there, and can avoid a fender bender. But when you're going much faster than that, of course the horn isn't going to help. If you're about to hit someone in an intersection, your attention and motor control is best spent with your hands on the wheel, trying to actually avoid the collision or minimize the damage, rather than moving one of your hands off the wheel in order to honk the horn.
The car horn is the pedestrian equivalent to "Hey!", which is used for a variety of situations, not all of which involve safety.
I sometimes wonder if we had easy car-to-car communication, making car travel more analogous to walking on the street, whether it would in general make driving a more safe and humane enterprise. I think there is an impersonal effect to sitting in a hunk of metal and glass without the ability to talk directly to those around us, and that it makes people inherently view those in other cars as competitors or obstacles, rather than as people. Until then we're stuck with the horn. And the wave and the finger.