Do we really need the old "danger" exception?

Lots of forehead-slapping absurdity in this Slate piece by Dave Johns on the history of the car horn. Like many car culture foibles, horn-honking has a long tradition of intractable drawbacks that outweigh any supposed benefits:

In theory, the horn is a safety device; it might rightly be called the world’s first "collision-avoidance system." But exactly how many collisions it serves to avoid has never been clear. From its earliest days, some observers wondered whether the horn wasn’t actually facilitating certain road mishaps by shifting the burden of evasion from the honker to the honkee…

By the 1930s, this judgment was gaining converts. First Paris and then London outlawed horn-honking at night. In 1935, New York Mayor Fiorello La Guardia kicked off a nighttime honking ban with a radio address in which he praised the English anti-horn effort: "The results have been so good that there is no demand from any quarter for their return. Automobile accidents, fatalities, and injuries have been reduced to an appreciable extent merely because the campaign against horns there has caused drivers to drive more carefully." He said deaths were down 17 percent and injuries 7 percent since the ban had taken effect.

In related news, aggressively venting frustration does nothing to relieve chronic gridlock.