So that the driver of a radio car will know what to do if someone darts across a street in front of his speeding machine, instructors of a police school at Hendon, England have devised an ingenious training method. The student is required to drive along a test course, and at some unannounced point a concealed catapult hurls a stuffed dummy in front of the car. Observers rate the driver on his ability to stop or swerve in time to avoid hitting the pedestrian. The catapult is operated by a spring, and a jerk on a rope releases its trigger. All drivers of London's police cars receive this training.