Feature article

What are driver assistance systems?

What are driver assistance systems and why are they so important? We break down all of the key information.

We may be a few years away from cars that can drive themselves, but many vehicles on the market feature increasingly advanced forms of driver assistance – giving us an insight into where car technology is heading.

Using the same cameras that help with Autonomous Emergency Braking, many vehicles can predict what’s ahead. Software identifies the edges of the road, and intervenes to keep your car within them. This can be done via a warning with a system called Lane Departure Warning (LDW), or by automated steering intervention with the Lane Keeping Assist (LKA) system.

How do these work?

The systems use one or more cameras mounted to the top of the windscreen, and sensors attached to the front and underneath the vehicle. The camera scans the road ahead in a 40-degree radius, picking up the lane dividing dotted white lines on a motorway or dual carriageway. When active at motorway speed, the car's computer management system recognises that the driver is following a particular lane.

Usually, the system will notify the driver it’s done this via a light or graphic in the instrument cluster.

The Lane Departure Warning system activates a warning buzzer, and in some cases even vibrates the steering wheel or driver's seat, if the vehicle moves out of its lane on motorways or roads, unless the indicator has been turned on in that direction.

If a Lane Keeping Assist system is fitted to the car, it’ll issue an audio and visual warning when the vehicle departs the lane and use the Electric Power Steering system to steer the vehicle back into its correct position.

If the Radar Cruise Control system is engaged, the Lane Keeping Assist function works to help reduce the driver's steering burden by assisting with steering. However, the driver must be holding onto the wheel or the system will deactivate – after sending a warning signal.

Not autonomous driving

Lane Departure Warning, Lane Keeping Assist, and Active Cruise Control are very much driver assistance features. They use the same base technology as autonomous systems, but are no more than an early form.

Even though the system can reduce the car speed to a standstill or intervene in situations such as lane departure, the car driver ultimately still has control of the vehicle. These systems shouldn’t be used at the expense of being a good, attentive driver.

How can I tell if my car has LDW or LKA?

You can check your car for a button showing parallel dotted lines with a small car veering out of them. When starting the car, the same symbol should illuminate on the dashboard momentarily and disappear once the engine is running. If the symbol remains alight, there may be an issue with the system.

When buying a newer car, ask whoever you’re buying the car from. It’s also often listed in the Trade Me Motors listing or in Trade Me car reviews.