How Lane Departure Warning Systems Work

How Lane Departure Warning Systems Work

Imagine commuting home from work in the evening. It has been a long day, and you are looking forward to getting home and relaxing for a few hours. You feel a little tired, and your attention begins to wander from the long stretch of highway you’re traveling. Eventually, you lose track of things for a few seconds.

Suddenly, an alarm startles you awake, and you see the lane-departure warning lights flashing on your dash. You adjust your course just in time to avoid running into the median. Your car’s lane departure warning system has spared you injury, damage to your vehicle, and possibly your life.

High Tech Protection

The RD-140 collision avoidance system by Safe Drive Systems provides lane departure warning while on the road. It uses high-end technology to track your car’s position between the marked lanes on the road, and gives you a warning signal when lane departure is imminent. It is a marvel of technology, and one that can save you from wrecking on the road. But how does it work?

Lights, Camera, Action

A lane departure warning system, or LDW, usually uses a camera to track the lanes on the road. Alternatively, some systems may use either lasers or infrared sensors to detect these lanes, but cameras are much more common. Usually, the camera is mounted on top of the windshield, though some other models exist in which it is installed elsewhere.

As you drive, the camera watches the road, and software is used to analyze the visual data, converting it into patterns that the computer system can recognize. This way, the system is able to “watch” the lanes and detect if you are getting too close to the edge.

If it becomes apparent that you are about to leave your lane, the system will give you a warning signal, usually an audible alarm and flashing signal lights on your dash, though there are some systems that will also vibrate the steering wheel or seat to get your attention in time to take corrective action.

Some systems will take action for you. These are known as lane keeping systems (LKS). They will use either brake pressure on specific wheels or your power steering to keep you in the lane if you don’t react in time yourself.

Both LDWs and LKSs will alert you only if you are not using signal lights. If you have your left turn signal on and drift into the left lane, for example, the system will assume you made the lane change on purpose.


Lane departure warning systems give you an extra measure of protection while on the road, but like any safety system, they are not foolproof. If the road is covered in snow or if there are no lane markings to begin with, the system has nothing to track and therefore cannot help you. Nevertheless, it is a valuable technology to have on board, and it can be worth the investment for the added safety it provides.

The Safe Drive Systems RD-140 uses camera-based lane tracking to give you an alert to lane departure in addition to its radar road scanner. To learn more about the RD-140, contact Safe Drive Systems today.

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