Some example vehicle restraints that include a movable barrier for selectively blocking a vehicle's RIG (Rear Impact Guard) near the dock face of a loading dock also include a spring loaded brace that helps hold the barrier in its blocking position, even when the RIG separates from the barrier. To hold the brace in its activated position where it supports the barrier, some examples of the brace include a tooth that engages a detent in a catch. The catch, in some examples, includes a tooth-engaging surface that protrudes into a circular path along which the tooth can travel relative to the barrier.