MOTOR VEHICLE TRAJECTORY MEASUREMENT

The present invention relates to measurement of the trajectory of a motor vehicle with respect to a roadway. A trajectory measurement system for a motor vehicle (1), comprises a sensing system (20, 21) for sensing the positions of roadway edges (5), a memory (24) that stores data relating to the width, and optionally lane width, of different types of road (4) on which the vehicle (1) may travel, and a data processor means (2) linked (26, 29) to the sensing system (20, 21) and memory (24). The processor means (2) compares the sensed positions of roadway edges (5) with the road width data in order to deduce the type of road (4) on which the vehicle (1) travels, and optionally also the lane in which the vehicle travels. The system may also include a vehicle speed sensor (13, 15) linked (33, 35) to the data processor means (2). The memory (24) then stores road speed data relating to different type of road (4) on which the vehicle (1) may travel, so that the processor means (2) can compare also the sensed vehicle speed with the road speed data in order to help deduce the type of road (4) on which the vehicle (1) travels.