Every motorcyclist has occasionally been frustrated a red traffic light that refuses to turn green because the vehicle detection system, tuned to deal with 4000-pound cars, does not detect the presence of his 500-pound bike.
In addition to carefully running the light after being ignored for a couple of cycles, a number of suggestions have been offered, including:
-where to position your bike relative to the wire loop embedded in the pavement
-using one foot to lower your bike’s centerstand so that it’s closer to the loop
-installing a powerful magnet on the underside of the bike
Here’s the thing. The loop in the pavement is apparently serving as an inductor. Knowing this, I have some questions, and I hope we can get some electrical engineers to provide the straight dope on what might help, or couldn’t possibly help, to get bikes to trigger these lights.
[ul][li]A considerable portion of the metal in a motorcycle is aluminum. Not just the cylinder heads, but often the cylinder, engine block, and frame and suspension components. Contrast this with cars, in which the engine block, frame and body are often made of iron or steel. Am I correct in assuming that the presence or absence of aluminum (and other nonferrous metals) doesn’t affect the behavior of an inductive loop?[/li]
[li]Does a stationary magnet affect the behavior of an inductive loop? IOW, could the product at the above link possibly work, or is it snake oil? If it could theoretically work, should we expect a magnet of that size to compensate for the absence of several hundred pounds of steel?[/li]
[li]Where should the mass of a motorcycle be positioned so as to produce the greatest effect (signal) in the loop, in order to maximize the chance of being detected?[/li]
[*]Should we expect the lowering of the bike’s centerstand down to the pavement to make any noticeable difference? The stand typically only weighs a few pounds, but if it’s within a couple of inches of the pavement (as opposed to a couple of feet above the pavement, for the rest of the bike), could it have a much greater effect?[/ul]