An improved parking lot traffic control means comprising an elongate series of tire engaging spikes extending transverse an entering and exit lane; said spikes are carried by an elongate shaft rotatably supported below the surface of the lane to project upwardly therefrom and from the surface of the...http://www.google.com/patents/US4101235?utm_source=gb-gplus-sharePatent US4101235 - Parking lot exit control means
