This invention is an improved structure for carrying out the concept disclosed in my earlier granted U.S. Pat. No. 4,250,395. That earlier U.S. patent disclosed a device which captured energy expended by pedestrian or vehicular traffic and included a plurality or tread plates which were depressed by traffic thereover to rotate a shaft through depression of rocker arms mounted to the shaft by one-way clutches. The rocker arms are normally spring-biased to a first position yet yieldable in response to the weight to movement downwardly so that the shaft, which is connected to a generator, is rotated to convert the mechanical energy into electrical energy. That structure described in U.S. Pat. No. 4,250,395 included a plurality of tread plates. This invention is of an improved tread plate means and general overall structure which is relatively simple to manufacture and assemble and constitutes an improved structure for accomplishing the use of vehicular or pedestrian traffic to convert the mechanical energy of the traffic to electrical energy.