A machine with a chassis and a push-roller assembly connected to the chassis. The push-roller assembly engages a vehicle, has a support frame with rollers, and support arms with a chassis end connected to the support frame and a linkage end connected to the chassis. The support frame moves relative to the chassis when the support arm pivots with respect to the chassis and the support frame. The machine includes an actuator controller associated with an actuator in the push-roller assembly. The actuator is connected to the support arm, causing the support arm to pivot with respect to the chassis and support frame, displacing the support frame relative to the chassis.