25 to be driven out and the spike to be removed from the socket and replaced if it is broken off during use transverse pin 44 preferably does not engage the adjacent second end 53 of spring 30 so that a degree of movement is permitted in the lever arm in the upright position as shown this pin extends through the central portion of the lever arm as shown in fig3 pin 44 serves to engage the adjacent portion of the spring member when the lever arm is moved by a vehicle travelling in the non permitted direction the non permitted direction of vehicle travel is shown by the arrow in fig5 for vehicle movement in this direction the resultant movement of the lever arm is to a position beneath the top surface of plate 12 the emergence of the piercing member 23 from beneath the plate to a position where it engages and harms the vehicle tire is shown as the lever arm 14 is urged in the direction shown by the arrow the pin 44 engages the second end 53 of the spring and is urged thereagainst deflecting this end of the spring in the manner shown the rotational mounting of the disks on the ends of each lever arm enable the disks to rotate along the surface of the tire as it moves in the direction of the arrow the envelopment of the exposed end of the lever arm by the vehicle tire which is characteristic of traffic controllers now in use does not take place with the result that there is no significant force tending to drive the lever arm in the counterclockwise direction in the prior art devices the tire frictionally engages and grabs the lever arm moving it in the direction of travel.