when u come from the airport to the Grand Hamad Street (bank street), crazy signal is the signal which is just before New World Centre signal (souq nabina).

about 8 to 9 years ago, there were two round abouts in that spot, a big round and inside a small round, which was confusin the drivers. so people used to call it crazy round about. and when they removed the rounds and installed signal lights, the name got carried forward eventually :-)

so thats how its called crazy signal, sounds crazy ;)