Friday, 30 September 2005 17:00

Camera, speed sensor, warning buzzer and indicator light combine to warn drifting driver

Written by I-CAR Advantage Online
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Many fatal accidents in the United States. are the result of a vehicle drifting out of its lane. A vehicle involved in a lane departure could lead to a collision with oncoming, following, or adjacent lane traffic. These collisions may occur as the result of driver distraction, inattention, or drowsiness. Lane Departure Warning (LDW) systems are designed to help prevent some of these collisions by alerting drivers of any unintended movement of the vehicle out of a traffic lane. At least one vehicle maker now has an LDW system available on some of its models. 

Infiniti system

Active Image
Figure 1. The LDW camera unit is located in-side the map light cover near the rear view mirror.

Infiniti is offering an LDW system on its 2005 FX crossover sport utility vehicle and 2006 M45 luxury sedan. The Infiniti LDW system uses a small camera, speed sensor, warning buzzer, and an indicator light to warn the driver that the vehicle is about to move out of its traffic lane.

The Infiniti LDW system recognizes lane markings through the use of the camera, which is located inside the map light cover near the rearview mirror (see Figure 1). The camera signal and the vehicle speed are sent to the LDW system control unit, which uses the information to calculate the distance between the vehicle and the lane marking and the lateral velocity to the lane marking. A determination is made, based on that distance and velocity information, as to whether the vehicle is moving out of the lane.

If it is determined that the vehicle is moving out of the lane, both the indicator light located on the instrument panel and the buzzer warning signals are activated, alerting the driver. The system will not operate if the camera does not detect the lane markings or if the vehicle speed is below 45 mph.

The Infiniti LDW system is temporarily disabled when the driver uses a turn signal. This action informs the LDW control unit of intended lane changes. There is also a manual cancel switch that allows the system to be shut off when desired. The system is automatically reset when the vehicle is restarted.

Other LDW systems

Similar LDW systems have been available on commercial vehicles for some time. Existing systems rely on optical and/or infrared sensors to determine the position of the vehicle relative to the lane markings.

A more widespread use of LDW technology is being worked on which could include other driver warnings, and/or integrating optical features with radar and GPS technology to provide more wide-ranging driver assistance. Features being developed include seat vibration, steering system feedback warnings, or a heads-up display warning on the windshield. A driver seat for example, could vibrate on the left or right side depending on the direction of the lateral drift.

Replacement/repair considerations

Replacing a collision-damaged unit will require removing the roof console, disconnecting the LDW camera unit connector, and the removal of the camera unit bolts. Installation of the replacement unit is the reverse order of removal. Avoid any impact to the camera unit. Camera aiming must be adjusted every time the LDW camera unit is removed or installed. Refer to the appropriate service manual for camera aiming adjustment.

The sensing capability of the camera unit can be affected by the condition of the windshield. Insure that the area of the windshield in front of the camera lens is clean and free of defects for proper LDW system operation.


LDW systems are now available on some 2005 and 2006 Infiniti models, so the possibility that they could show up in a collision repair facility exists. If one of these models is in your facility, be aware that it may be equipped with an LDW system. It is important to maintain the reliability of these and other safety systems by providing complete, accurate, and safe repairs.

This Advantage Online article first appeared in the I-CAR e-newsletter, which is published and distributed free of charge. I-CAR, the Inter-Industry Conference on Auto Collision Repair, is a not-for-profit international training organization that researches and develops quality technical education programs related to collision repair. To learn more about I-CAR, and to subscribe to the free e-newsletter, visit or contact I-CAR Marketing Communications Specialist Brandon Eckenrode at Brandon.


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