FLASH: A disabled vehicle detection system

The flash lights and send help (FLASH) system uses an electro-optical detector designed to enable passing drivers to conveniently summon assistance for motorists in distress. The driver signals at designated reporting stations by flashing his high-beam lights three times. A roadside unit detects the headlight flashes and transmits an identifying tone signal to a central monitoring station, whose operator dispatches a service vehicle to the section of road under that detector's jurisdiction. The detector performs reliably over a range of 1000 feet during daylight or darkness, bridging an illumination ratio of up to 1:10 000 000 without a mechanical iris. The concept, design, and mechanical construction of the system is discussed in relation to the technical fulfillment of practical operational requirements. These include day and night operation, variations in temperature and weather conditions, random reflections, public safety, pranksters, vandalism, and repair and maintenance. A detector knockdown alarm, system test mode, and an audio alarm are incorporated on an illuminated road-status display panel located at the central monitoring station. A prototype system is presently being installed on a 50-mile (80-km) section of Interstate 4 between Tampa and Orlando in Florida, and will be operated by the Florida highway patrol during a 1-year evaluation period.