A fail-safe circuitry for a vehicle barrier security system prevents accidental raising of the barrier due to inadvertent closing of an activation relay causing power to be provided to an activation mechanism raising the barrier. A latching relay, having a latched state and reset state, is placed in series between the activation relay and the activation mechanism. The latching relay is reset whenever the OPEN switch is pressed for lowering the barrier or an automatic reset relay is energized by a controller whenever passage of a vehicle is sensed. Prior to raising the barrier, the latching relay must be reset, which can occur by pressing the OPEN switch or by the controller detecting passage of a prior vehicle and activating a automatic reset relay. Accidental raising of the barrier due to malfunctions of the activation relay due to vibrations is prevented by latching and resetting the latching relay.