Actually, many vehicles seem to have auto-correcting Lane Keep Assist systems as well, which take Lane Departure Warning systems a step further by actively correcting the vehicle’s direction when it wanders too far out of the traffic lane rather than just passively alerting the driver to the problem. These “active” systems also typically use lane markings for reference (though a few systems do use the road edge to judge road position instead of lane markers so, again, it’s critical to consult service information for the exact vehicle involved to understand the systems used) and the control module decides when corrective actions are needed and acts accordingly using the steering or braking systems. Even though corrections are made without driver input, the computer’s corrections can typically be overridden by the driver using the normal steering controls – and the system can be completely disabled if desired.
And as with Lane Departure Warning systems, the Lane Keep Assist systems aren’t foolproof either. The systems can be adversely affected by reflections from road debris or large shiny objects or trucks that reflect into the camera so the driver (or technician test driving the vehicle) still needs to be vigilant and maintain control.
|Drivers tend to disable the systems when false activations become annoying or distracting.|
System limitations aside, however, there are a few things to be mindful of when servicing vehicles with Lane Departure Warning and Lane Keep Assist systems to avoid inadvertently causing problems.
For example, even though systems vary among manufacturers most vehicles use a camera located in the base of the rear view mirror at the top center of the windshield in the system. And since light travels back and forth through the windshield to the camera, using non-OE quality replacement glass has been known to adversely affect the system’s operation, as have dark tints and even just general grime on the windshield. In fact, anything in the path of the camera can adversely affect system operation so it’s important to be careful when working in that area.
(A few manufacturers do use a more expensive radar-based system for their lane departure warning systems, with the sensing unit mounted at the front of the vehicle, usually in the front bumper or grille area – so always consult service information to be sure.)
Also, if the system vibrates the seat to alert the driver to problems, keep in mind that the vibrating motors inside the seat use wiring harnesses that may crack or break if abused (broken or crushed harnesses have been known to happen in certain light-duty trucks) so be particularly careful about throwing anything onto or under the driver’s seat – the harnesses may not like the extra stress.
And finally, like any other computerized system or program, Lane Departure Warning and Lane Keep Assist operation is only as good as the inputs and outputs. It’s a nice touch during routine service to clean any dirt, bugs or grime from the sensors so that the system operates as reliably as possible. It’s a small thing but it’s a professional touch that can make a difference when your customer decides where to bring their vehicle for the next service.
|it's important to keep the sensors free from dirt and bugs.|
|Even general grime on the windshield — like this — can affect system operation.|
Collision Avoidance Systems
Another safety feature that used to only appear on higher-end vehicles but is fairly common now is the Collision Avoidance System that warns drivers of impeding front end collisions so they can take evasive action – or in some cases brake or steer the vehicle without any input from the driver at all.