Speed control system for road vehicles - uses spaced magnets set in road to provide pulses in detector comprising logic circuit on vehicle with time interval related to speed

摘要

The control system uses markings on the road consisting of spaced bands lying across the road at a depth of about 30 cm. Each band comprises a number of permanent magnetic elements, and the separation between the bands is proportional to the maximum permitted speed on a particular road. Vehicles are provided with a detector sensitive to the magnetic field above the magnets set in the road. The detector (5) is connected to a time delayed pulse generator (6). Both the detector output and the pulse generator output are connected to an AND-gate (7). Successive pulses from the detector arrive within a set time then the AND-gate provides an output to a recording device (8) indicating that the vehicle is exceeding the speed limit. By using bands with varying spacings different speed limits may be imposed.