MANHOLE VEHICLE SENSOR

A utility worker seeking to exit a manhole (13) in a roadway (14) receives a warning of an approaching vehicle (12) via a warning device (18) within the manhole and signaled from at least one vehicle-detecting device (15) on the roadway for detecting approaching vehicles. The vehicle-detecting device (15) includes a motion detector (19) for detecting the approaching vehicle by its motion and, preferably, a noise detector (20) and band pass filter (22) for detecting the approaching vehicle by its motion. The motion detector (19) provides a “far end” or early warning of an approaching vehicle, whereas, the combination of the noise detector (20) and filter (22) provide a “near-end” or late warning. The combination of near-end and far-end warnings increases the margin of safety afforded the worker seeking to exit the manhole onto the roadway, in contrast to a far end or near end warning by itself.