Abstract: A guidance system for a vehicle designed to follow a two-way track and having pneumatically tired steered wheels coupled to a directional arm. The system includes a rail with a rolled steel section having a head supported on a web strengthened by a lower foot projecting from each side of the web; the head is bounded laterally by receding inclined lateral faces. A grooved roller follows the rail, and floats at an end of the directional arm of the vehicle.