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What is lane assist?

Buying a new car doesn’t have to be difficult – after all, that’s why we started carwow. But sometimes just choosing the equipment for your new wheels can be tough, thanks to indecipherable acronyms and new technologies.

To help, we’re here with a series of guides to help explain some of the more modern technologies that you might not have seen on a car. This week, we’re looking at lane assistance systems.

Variously called Lane Assist by Audi and Volkswagen, Active Lane Keeping Assist by Mercedes, Lane Departure Warning by BMW or Lane Keeping System by Ford.

What is it?

Covering seemingly endless motorway miles can take its toll on drivers. Many accidents on the open road happen because of drivers being tired or temporarily distracted and drifting out of their lane. Lane assist systems, available on most new cars, monitor the car’s position on the road, detect if the driver is unintentionally leaving their lane and react either through warnings or by actively steering the car back into its lane.

How does lane assist work?

Lane assist is simply the next step towards cars becoming more self-aware and more able to stop an accident before it happens. The American National Highway Traffic Safety Administration (more snappily known as the NHTSA) suggests that about 5 per cent of reported crashes occur when driver are merging with fast-moving traffic or changing lanes.

Lane assist systems warn the driver if they are unintentionally straying out of lane in an effort to reduce this figure.

Using a variety of sensors, most commonly a wide-angle camera placed in front of the rear-view mirror, the systems identify where the lanes are and monitor the car’s position in them, commonly at speeds above 40mph. If the system detects the driver is about to leave their lane it alerts them with an audible warning and, on some models, a vibration through the steering wheel.

How does active lane assist (lane keeping) work?

The problem with lane assist is that particularly inattentive drivers might still ignore the warnings they receive, meaning they just get notified about the impending accident rather than saved from it. Active systems physically intervene and, in the event of a lane departure, will gently steer the car back into its lane.

Don’t get excited about hands-free motoring just yet: the system generally deactivates if it detects you are not holding the wheel.

Systems that can steer the car, such as those on Audis and Volkswagens, typically use the electronic power steering system to apply a steering input to drag the car into line again. Other systems, like those on the Mercedes C-Class (shown above), operate using the brakes to steer the car back into its lane.

The systems deactivate when you’re indicating, assuming that you are intentionally changing lanes, though blind spot warning systems can still keep a watch over your shoulder. The very latest systems have intelligent programming that can tell if the driver is driving enthusiastically so will not warn the driver in this case.

Who uses it?

Almost every mainstream manufacturer will offer some form of lane assist on most of their cars. VW, Audi and BMW all offer systems that will warn the driver if they drift out of lane. Mercedes and Ford are just some of the manufacturers to offer active lane keeping which actually steers the car back into its lane.

Any drawbacks?

Most systems have been tuned not to warn the driver at low speeds where crossing lanes is common practice. However, no system is infallible and they can get confused by unusual road layouts or faded or obscured road markings, meaning the driver can be falsely warned of a lane departure.

Anything else I need to consider?

Many manufacturers, such as BMW and Audi only offer lane assist when purchased in conjunction with other driver assist systems such as blind-spot indication, adaptive cruise control or collision-avoidance braking. So if you’re set on having this safety system expect to have to purchase some other ones, too.

Is it worth it?

As mentioned, lane assist typically comes as part of a safety pack, meaning that it’s bundled up with other options, which pushes up the price. Of course, if safety is your most important concern then it’s an invaluable option that helps reduce the chance of an accident happening in the first place.

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