"Cars have a very regular pattern with the way they move, whereas when people are riding bicycles they change between either acting like cars on the side of the road," says Rowe, an associate engineering professor at Carnegie Mellon University. "They might switch and become pedestrians and go up on the sidewalks. They tend to move in a slightly more erratic way. It's much harder to predict."
exactly. it is why cyclists are a challenge for humans as well. far less predictable than how people drive motor vehicles.
an alternate to transponders is to require cyclists to follow the rules of the road.