Infiniti, the luxury division of Nissan North America, has announced the availability later this year of a new Lane Departure Warning (LDW) system, which alerts drivers of an unintended movement of the vehicle out of a designated traffic lane.

The new system, which uses a small camera, speed sensor, an indicator and an audible warning buzzer, will be offered this autumn on the 2005 FX crossover sport utility vehicle - the first production application of LDW in North America. The system will also be available on the next generation M45 performance luxury sedan, which is scheduled to go on sale in spring 2005 as a 2006 model.

"Studies show that 55% of fatal accidents in the US are caused by lane departure," said a Nissan North America spokesman. "These are caused by various factors, including driver distraction, inattention or drowsiness. The Lane Departure Warning system generates a warning to help alert the driver that the vehicle is about to move out of its lane."

The Infiniti LDW system is temporarily disabled by driver activation of the vehicle's turn signals, which informs the system's control unit of intended lane changes. The system also features a manual cancel switch, which allows the driver to turn the system off when desired. The system automatically resets when the vehicle is restarted.

The system recognises lane markings through the use of a small camera mounted behind the rear view mirror. The camera's signal and the vehicle's speed are sent to the microprocessing unit, which combines the information to calculate both the distance between the vehicle and the lane marking and the lateral velocity to the lane marking. A judgment is then made as to whether the vehicle is moving out of the lane (depending on the distance and lateral velocity to the lane).

If it is determined that the vehicle is leaving the lane, both visual (indicator light located on the instrument panel) and audible (buzzer) warning signals are generated, alerting the driver to take corrective action. The system will not operate if the camera can't detect the lane markers or if vehicle's speed is below 45 miles per hour.

The system was developed in conjunction with Valeo and Iteris; the latter that has previously developed LDW systems for the commercial long-haul truck industry.