Here are some links about tripping traffic sensors. Any conductive material will work - aluminum rims actually trip the sensors better than steel...


http://www.humantransport.org/bicycl...nals/green.htm
http://www.bikexprt.com/bicycle/actuator.htm


and for the technically inclined:
http://humantransport.org/bicycledri.../detection.htm


- Jeff "yes, I'm a tech geek" M.