听力原文： As the car industry develops, traffic accidents have become as familiar as the common cold. Yet their causes and control remain a serious problem that is difficult to solve.
Experts have long recognized that this discouraging problem has multiple causes. At the very least it is a problem that involves three factors: the driver, the vehicle and the roadway. If all drivers exercised good judgment at all times, there would be few accidents. But this is rather like saying that if all people were honest, there would be no crime. Improved design has helped to make highways much safer. But the number of accidents continues to rise because of human failure and an enormous increase in the number of automobiles on the road. Attention is now turning increasingly to the third factor of the accident—the car itself. Since people assume that accidents are bound to occur, they want to know how cars can be built better to protect the drivers.
What are the factors that are involved in traffic accidents according to the passage？

A. The driver.
B. The vehicle.
C. The roadway.
D. An of the above.