Watch out for these. One SICK laser (german company) embedded in the guardrail and a 2nd unit with the flash & camera a few meters behind make up this kind of fixed speed trap. These units can distinguish all by themselves if a car, truck or motorcycle is speeding, making it possible to enforce different speed limits without the use of sensors buried under the road or the use of scales, the SICK lasers figure the type of vehicle out by
themselves and they can track as many vehicles in all lanes on the highway.
Laser embedded in guardrail:
