Extra eyes: Automotive lane departure warning/keeping technologies

Volvo lane departure warning system

Volvo’s lane departure warning system scans the road ahead to identify lane markings.

We’ve all been there: we start a drive with too little sleep, thinking that a full tummy and some good tunes will keep us awake on our trip. Unfortunately, reality sets in as we are jolted awake when the car hits the Botts dots on the road. Not good.

With today’s technology, manufacturers are working hard at keeping us awake and alive. One way is through technology that alerts drivers if they wander out of their lanes, usually due to inattentiveness or drowsy driving.

While these lane-departure warning systems were introduced in Japan almost a decade ago, they’ve finally migrated to the United States, and not a moment too soon. According to statistics from the AAA Foundation for Safety, more than 40 percent of Americans say they have nodded off or fallen asleep behind the wheel — a scary statistic.

There are now several manufacturers selling vehicles in America with these potentially life-saving devices. While the majority of them are on luxury vehicles (Audi, BMW, Mercedes-Benz, Infiniti, Lexus and Cadillac), Ford recently announced it would offer its version of this technology on upcoming – more affordable – vehicles.

Audi’s Lane Assist feature uses a forward racing camera to detect whether the vehicle is drifting toward a lane marking, and will vibrate the steering wheel to alert the driver. This system will not intervene if the vehicle does drift over the line, and works at speeds above 60 km/h, or about 37 mph.

Mercedes-Benz offers Active Lane Keeping Assist, which also uses a camera to watch for lane departures. It will vibrate the steering wheel as well as gently apply braking to the wheels on the opposite side of the drift area of the lane to help keep the vehicle in line. A warning symbol also is posted in the instrument cluster to alert the driver.

Infiniti lane departure warning system view

How Infiniti’s lane departure system “sees” the road ahead.

Infiniti introduced its Lane Departure Warning and Lane Departure Prevention systems in the new M sedans. Again, a forward camera scans the road to watch for lane departures. If it recognizes signs the driver is drifting out of the lane, it will provide a visual display on the dash along with an audible buzzer. If the vehicle correction is not made, the prevention system kicks in by applying the brakes to help move the vehicle back into its lane.

Volvo, Lexus have similar systems to Mercedes and Infiniti, while BMW’s system will vibrate the steering wheel like Audi, without any other intervention. Cadillac’s system will flash an amber light and provide an audible warning when the vehicle comes close to or crosses the line.

With all of these systems, regardless of manufacturer, if the driver is using the turn signal to indicate an lane change, the systems will not activate as they can recognize the intention to cross the lane marking.

Early next year, Ford will introduce its Lane Keeping System in the 2012 Ford Explorer. This technology offers three unique features that will help Explorer owners (and soon after other Ford vehicles) arrive safely at their destinations.

Driver Alert System
As you start to get drowsy, obviously your attention to the road fades and your grip on the steering wheel lightens, which in turn allows the car to drift outside the center of the lane. The Driver Alert System is constantly monitoring the vehicle’s movement compared to lane markings via a camera on the windshield. The forward-facing camera is mounted at the vehicle’s centerline, and the camera module is integrated into the rearview mirror. Electronic messages are relayed back and forth with the steering system. Once the system determines that the vehicle is following a driving pattern consistent with a drowsy driver, the warnings begin. First, a chime will sound, and then a pictograph of a cup of coffee appears in the instrument panel cluster to suggest the driver pull over and take a break, in addition, a visual warning comes on the message center alerting the driver to stop and rest. If the vehicle continues to move or doesn’t respond to the chime, a second warning chime will be issued. The warnings stop if the driver pulls over and either opens the door or shuts off the engine.

Lane Keeping Alert
Ford’s Lane Keeping Alert feature is great for drowsy drivers, but also for those who are distracted and allow the vehicle to wander across the line. If the system detects the vehicle drifting closely toward the lane markers, it will send a vibration to the steering wheel to remind the driver to pay attention and maneuver the vehicle back into the proper lane. This system uses the same camera and technology from the Driver Alert System, but also provides a display in the instrument cluster to let the driver know the system is working, as many roads sometimes are not well marked.