Nearly every traffic light road sensor here is an inductive loop which detects the ferrous steel in the steel belted tyres / frames - we usually used to test them using a metal tool box just on the corner of the loop. I know when the loops get a few layers of seal over them (about 3inches) they would stop working (unless a truck parked up on them) and we would have to put in new ones.

Also have some sites with cycle lane sensors which are a scaled down version of vehicle loops.  They never really took off since most push bikes (roadies especially) are made of very little amounts of ferrous material anymore.

Where we had really busy sites with broken loops, we used to use temporary microwave sensors to detect cars moving up to the intersection - these picked up everything including pushbikes and motorcycles. Microwave sensors were pricey and difficult to align (and also suffered from reflections).

I know from some of the spares we had out the back that they used to use a pressure hose at right angles to the road - this would activate a simple pressure switch.  I don't think we really used these much here.  Only other sensor is the Piezio type which was mainly used here for classification/counting sites or the old speed camera sites were you need the absolute accuracy (although our new mobile and fixed speed cameras use digital analytics and 1 camera can cover up to 10 lanes in either direction with no active (detectible) systems like Laser or Radar). 

I can say that camera systems are probably going to take over, since they can be used for detecting red light runners etc. also.

Quote from: tmbr_wulf on October 03, 2013, 10:48:55 AM
I agree.  As long as they're not there the entire time there's probably some doubt there that you could wiggle through in the event that they tried to call you on the 120 second rule.  What I would love to see is a motorcycle at the head of a line of traffic stopped at a long light just get up and go leaving all the cars sitting there.  While it could technically be legal it could bring some heat on the law if it were abused like that.

Lol, I have actually done that... and I thought about that very thing before I did it too, haha
 
But... the guy behind wouldn't pull up!  He was two full car lengths behind me and he couldn't understand what I was trying to get him to do, so I finally just said Eff it... looked both ways and went.  Maybe he had an epiphany when the light turned after he pulled up?    Not like I sped off or anything squidly, but I had to move, I was getting drenched from sweat sitting there too long.

- Bboy

Only time I was ever pulled over on a bike was for doing this. It was later at night and I came to an unfamiliar T-junction waiting to turn left. Sat there forever and ever and it never changed. Lucky for me there was plenty of visibility on both sides. So after waiting a good 5 minutes I finally proceeded through the red light. Just as I was about halfway through the turn I saw lights come up behind me (the road leading to the t-junction where I was turning off of was heavily curved). About 5 seconds later the blues came on and I immediately pulled off the road.

Cop came up and immediately asked me "You know I saw you run that light, right?" to which I replied "Yes officer, I'm aware of that." He kind of paused and then asked "Well, why did you run the light?" to which I replied "Because I had been sitting there for a long time waiting and I figured either the light wasn't registering me or it was broken." He asked "How long is a 'long time'?" to which I replied "At least 5 minutes maybe longer."

I'm pretty sure he wanted to give me a ticket but couldn't do it because he sort-of begrudgingly said "Well...okay, next time you need to wait longer." and I said "Alright officer." and that was the end of it. It was over and done in about 2 minutes probably less.

Just goes to show you...just when you think somebody isn't looking...they are.

this is true. very true. i bust em on the goped  often. ( least until i blew the engine lol) it weighs 42lbs wet, me, im 141 lol. so it will NOT trip one of those lol.

In other countries running a red light is a requirement almost. Driving in Mexico City at night, I was told not to stop at any red light, but to get close to the light look and proceed. Do not stop totally as go give the carjackers and opportunity to take advantage. That rule only applied to after dark traffic. Most importantly not to get in between 2 cars that are driving close together. Supposed to be somebody with bodyguards and don't mess with them.