The state’s top court has back-pedaled on a trial judge’s finding that a law defining “low-speed gas bicycles” is unconstitutionally vague.The Illinois Supreme Court unanimously ruled this morning that the Vehicle Code’s definition of the motor vehicle — which provides that such bikes have less than one horsepower and a maximum speed of 20 mph when operated by someone weighing 170 pounds — is reasonable for both riders and police officers alike.Justice Rita B. Garman authored the …