Active road stud which reduces its power consumption in the absence of vehicle headlights

摘要

A road stud for disposal in a road surface comprises a light sensor 24, a microprocessor 30 and a light source 18. The light sensor senses incoming light â Aâ from a vehicle on the road and outputs associated sensed light data. The microprocessor analyses the sensed light data so as to detect vehicles with their lights on. The light source (e.g. LED) emits light from the road stud and the microprocessor reduces the power drawn by the light source (e.g. by reducing its intensity or frequency) when no vehicles with their lights on have been detected for a predetermined period of time. The light sensor may be a photodiode, phototransistor, photo-resistor or a solar or photovoltaic cell. The stud may include a power supply 14 and data storage device (e.g. memory 38).