| 摘要 |
The device uses a speed detector (7,8) which detects the speed in a vehicle approaching the speed-restricted stretch of road (1) and changes the traffic signal (2,3) from green to yellow if the speed of the vehicle exceeds a speed limit. The speed detector changes the traffic signal from yellow to red if the speed of the vehicle continues to exceed the speed limit after a predetermined time interval, thus causing the driver of the vehicle to stop. Lasers can be employed for speed detection purposes, with parallel control of traffic signals by means of control signals dependent upon the detected speed. - The lasers do not have to be arranged in direct connection with the traffic signals, but can be at a distance from them. Their control signals can be transmitted to the traffic signals by wire or wireless. It is also possible for the speed detection to be made by radar apparatus, magnetic coils placed in the road surface or similar. |
