A cam actuated hydraulic brake system and an in plane tensioner pulley belt drive system may be used on autonomous vehicles, such as dynamic motion elements for the evaluation of various crash avoidance technologies. The brake system utilizes a cam driven by a servo to push the piston push rod of a hydraulic master brake cylinder, thus distributing pressurized brake fluid throughout the brake system. The pulley drive system uses an articulating arm for the driven pulley, and that arm may also have connected to it one or two tension pulleys, each of which is in contact with the belt. Because the drive pulley and the tensioner pulleys pivot about the same pivot axis, the needed belt length remains nearly constant across the entire range of the articulating arm.