Pedal assemblies for motor vehicles. In one implementation a pedal is pivotable around a shaft that is releasably fixed in a housing of a support piece by a retention member. The retention member is moveable between a first position corresponding to a normal operating condition and a second position corresponding to a head-on collision condition. In the first position a first part of the retention member rests against and holds the rotating shaft in the fixed position within the housing of the support piece and a first surface of the retention member rests against a guide surface of the support piece. The retention member is releasable from the support piece upon a force being applied to it in the event of the head-on collision, the first surface of the retention member adapted to ride along the guide surface of the support piece to cause the retention member to move from the first position to the second position in a manner that causes the first part of the retention member to be moved away from the rotating shaft so that the rotating shaft is moveable within the housing.