Originally Posted by michaelalanjone

I don't see how it could be triggered by a magnet, unless there was a magnetic reed switch, activated by a movable slab that had a magnet attached to it, or some sort of magnetic field sensor. Both are doubtful.

The switches (at least around here) are usually triggered by weight. My old motorcycle didn't set some of them off (it was a light bike, at 550 lbs + my weight, 175 lbs = 725 lbs).

Options:

1. Ride a Huffy Roadmaster.
2. Eat at McDonald's every day for a month.
3. Stop, and if the light doesn't change, run it.

I always opt for #3.