Quote Originally Posted by dragons_fire View Post
i would pulse the lasers on one side with a 555 or a micro, then recieve that pulse on the otehr side with a second micro, that way you wont have any wired going across the road, and oterh light sources wont interfere with the results...
You wouldn't need the laser to be on the other side of the road, just put the emitter and the detector on one side, seperated by a few inches or whatever. A car goes by, you'll get a reflection. You may need a bit of a wide angle detector for this though. And make sure that there isn't a mirror or something like that across the road...