It only takes a second. You take your eyes off the road to check your navigation system, or reach for a CD, or spill coffee in your lap, or any one of dozens of other things that can cause you to lose orientation on the road, and your vehicle drifts the tiniest bit out of its lane, just enough to cause an accident that could end up in tragedy. It was in 2003, in Los Angeles, California, that a motorist dropped his cell phone and took his eyes off the road for just a moment, drifted slightly, and struck and killed a jogger on the side of the road. That accident, and several others like it, are the main reason automotive manufacturers designed lane departure warning systems. Just in case you haven’t driven a vehicle with one of these systems, or don’t know much about them, we’ll take the time to explain a little about what they are, how they keep you safe, and give you some examples of vehicles that now come equipped with this new safety technology.

There are two main types of lane departure warning system. There is the standard “warning” system, which warns the driver via audible sound, steering wheel vibration, or some form of visual warning when the vehicle begins to drift from its lane. Then there is the Lane Keeping System (LKS). This system first gives a warning that the vehicle is leaving its lane, and if no action is immediately taken, it takes steps to ensure that the vehicle stays in its lane. It does this through a series of sensors that utilize laser, video, and infrared technology.

The most common of these sensors are laser sensors mounted on the front of the vehicle, and a video sensor typically mounted on the rearview mirror. There are other types of sensors used by various manufacturers, but they all exist to accomplish the same task – keeping the vehicle where it’s supposed to be. These sensors pick up the dotted white lines and road reflectors on the road to determine what lane you’re in. The rearview mirror cam usually scans a forty-degree radius and sends the signal back to the computer, which then uses the laser sensors mounted on the front of the vehicle (or optical sensors mounted on either side in some models) as tools for directional guidance. The vehicle scans the road for a certain distance ahead; it then determines the proper path the vehicle should be taking. If it senses a stray from that path, it will issue a warning. Most of the time these warnings include some form of audio sensor and a light vibration in the steering wheel, similar to what a driver would feel when driving over rumble strips.

In many new model vehicles the warning system is also accompanied by the correctional system. In this system, once the audio and steering wheel warning sound, if no action is taken by the driver, the computer can use light torque in the steering to correct the line of travel. The most common question among new users of the system is, “What if I actually wanted to change lanes? Is this system going to fight with me?” The answer to that is, as long as you follow traffic laws and use your turn signal for lane changes, no, the vehicle will never interfere with your driving.

If this is a new safety technology that you’d be interested in, here are a few of the better-model vehicles that are now coming equipped with it:

2011 BMW 5 Series

2011 Mercedes-Benz E-Class

2011 Cadillac STS

2011 Kia Cadenza

Some models that don’t possess the full LDWS, but do share the same technology by possessing its cousin, the blind-spot warning system are:

2011 Ford Fusion

2011 Audi A4

2011 Buick LaCrosse

2011 Ford Taurus

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