The bicycle turn signals I have seen for sale are small, cheap looking, and don't make it obvious to those behind you what your intentions are. Not to mention they don't tell oncoming traffic what you are doing. I suggest making a homebrew turnsignal system bright enough to alert drivers from a distance during daylight hours. Sort of like mine.

http://www.bikeforums.net/attachment...1&d=1188097283
http://www.bikeforums.net/attachment...2&d=1175739939


I tried using an automotive blinker, but it is a thermal device and relies on the resistance of an incandescent bulb as part of the circuit. It didn't work with the LEDs. I tried using a solid-state automotive blinker that was supposed to work with LEDs, but it didn't work either. Huh. I ended up building a circuit from the "Total Geekiness" sticky on the Electronics, lighting and gadgets forum.

The lights also serve as daytime running lights.