Abstract: A series of magnetized cylindrical rollers are rotatably mounted in spaced transverse channels under a freeway off ramp. Each roller is made of non-magnetic material and has plurality of cavities around its rim in which arcuate bar magnets are mounted. The bar magnets are arranged with like poles adjacent each other to produce magnetic spokes which penetrate the off ramp and extend into the space traversed by vehicles travelling along the off ramp. Motion of the vehicles induces rotation of the magnetic rollers by magnetic interaction with the magnetic spokes. Electrical generators are coupled to the rollers to change their rotary motion into electrical energy.