The City Council has approved a bill that would ban the sale of most car alarms in NYC, specifically the "sale and installation of audible alarms that are motion-activated or that sound for longer than three minutes" (NYTimes). Three minutes? That's cruel - it should be two minutes. And another thing - motion-activated alarms should not be allowed in the city period - this city is all about huge buses and heavy trucks rumbling by, shivering the streets' timbres. Anyway, it's a nice move in attempting to reduce noise pollution, but it might be limited, as the bill, which prohibits the sale and use of car alarms in the city, wouldn't affect car alarms that are pre-installed in cars or installed outside the city (!!!) which is why the Mayor may veto the bill.
How Stuff Works on how car alarms work. And Gothamist on the City Council's first rumblings of this car alarm bill, right after the Mayor's noise reduction initiative was announced.