Distinctive Cab Horn

In Chicago, cab drivers are often in the habit of honking at pedestrians who look like they might need a cab, but just haven't noticed them. This is great for times when you were looking for a cab but got distracted by the girl in leather and white face paint walking by - you turn to see what the honking's about, and there's a beautiful orange empty cab looking for someone with money to come out of the cold.

There are a couple of downsides to this method. First, it leads to a lot of honking, sometimes unnecessary. It's a little unnerving to be honked at when you aren't looking for a cab. Second, all honks sound the same. There is a lot of honking in Chicago, and you're not always going to turn and look at what's going on.

I propose that cabs be allowed to use a distinct "cab signal" sound. It should be fairly unobtrusive, maybe recorded bird chirping or something similar. All cabs should use the same sound. This would prevent people from thinking that there is some sort of emergency coming through, and would alert people looking for a cab that there's a cab in the vicinity looking for a fare.

The easiest application would be to have the sound emanate from the light fixture that's installed on the top of all cabs.