Well I have to admit the rest of your post confuses me completely
But as far as I understand, the AMB system works by each active transponder sending an ID with a random time between (to remove collisions if more than one crosses the line).
What I don't understand is how they use inductance to send an ID. Perhaps some form of RFID would work, but I don't know enough about it. So are there any RF or similar devices that can:
1) Detect quickly enough for a vehicle travelling between 10-20mph
2) Be reliable to detect with some accuracy