Comfort Zone. In our western society a lot of people (fewer each day) have their secure jobs, homes and social background. Living in a "secure world" tempts to stay conform and accept the world how it is. We amuse ourselves with movies, gadgets, theme parks and so on, trying to seek a thrill were there is none. Bumper cars are designed to have fake accidents with other cars in a controlled secure surrounding. The visualization of an real accident with a bumper car, which is actually an impossible event, is a synonym for breaking out of "safe" routines and go out and leave once comfort zone behind.