Here in Bangalore, too, most roads have lanes. But what's different from other countries like the US and Japan is that people completely ignore the lanes. Actually it might be better to say that they seem to consider a line dividing the lanes to be another lane. So, if you have one lane dividing a road into two, people consider it as a three lane street (^^)v
Anyway, it is mainly the reason why people honk all the time, as you cannot really see what's behind you on the side mirrors. Honking is considered to be a friendly precaution to let other drivers know where your car is.
One thing I noticed is that most of the auto rickshaws turn their engines off at the intersection when the light is red. You can pretty much enjoy the moment of "quietness" (note that the honking on the cross road continues) for a while, and then right before the light turns green, the engines and honkings start as if everyone is going on a race or something. The sound is not that unpleasant, though. It pretty much reminds me of the philharmonic members tuning their instruments before the concert. It is actually musical :)