Technology makes everyday driving situations safer.

By Bill Machrone

Every year, an estimated 826,000 accidents related to blind spots occur. Every car has a blind spot, and you've probably missed seeing a car that's driving in yours — or vice versa. Additionally, you've probably drifted out of your lane on occasion. So how can blind spots and lane drifting be overcome?

Automotive engineers have been hard at work on both problems, with technology that can warn you if the lane beside you is occupied or if you're beginning to drift out of your lane. Many manufacturers now offer detection systems as options or build them into their higher-end models.

The simplest blind-spot solutions rely on the oldest detection system: you. These simple and affordable gadgets use you as the main detection system:

• Domed Mirror – The easiest and least expensive by far, this small stick-on mirror greatly increases your field of view, more like the convex mirror on the passenger side. Driver's side mirrors must be flat in the U.S. to aid distance-judging, even though they restrict your view, so you must reconcile what you see in the two mirrors.
• LaneFX – The next step up, this system sweeps your mirror when you signal so you can see what's next to you as well as what's behind you. Of course, you have to look, or the assist is wasted. LaneFX is available through aftermarket installers.

Automotive manufacturers use several technologies for blind spot detection, such as:

• Radar – Buick's radar-based system has warning lights mounted in each of the outside mirrors, so when you check your mirrors, you'll know whether it's safe or not.
• Dash-mounted Displays – Some manufacturers, such as Mercedes-Benz, use dash-mounted displays with optional audio tones to signal a car in either rear quarter. Volvo mounts warning lights on each of the front pillars.
• Cameras – A number of automakers are adding optional cameras that give drivers a view of blind spots particularly of objects directly behind the car. The images are typically displayed on a video monitor in the dashboard or behind the driver's sun visor.
• Thermal Imaging – To aid drivers at night, infrared detection systems are being included as an option on some trucks and in a number of car models from Volvo, Mercedes-Benz and others. These systems typically look ahead of the vehicle and project images of cars, animals, tress and other objects onto dashboard video display systems.

 According to driver reports, the technologies are equally effective and need not be a reason for choosing one car over another. Drivers are very positive about the systems, typically saying that all cars should have them.

Lane Departure Warning Systems

Lane departure warning systems (LDWS) are inherently more complex than blind spot detection because they must determine the edges of the lane (whether you're approaching them purposely or not), your car's position relative to them and even your driving style.

Lane departure systems use video cameras and infrared sensors, usually located behind the rear-view mirror, sometimes in the front bumper. They look for divider lines and lane dots, continually building a predictive map of where the road is going, then watch to see if the car is following it. The system sounds an alarm and flashes if the car drifts too close to a lane edge without sensing intention from you, such as steering wheel input or a direction signal.

Some systems are specifically attuned to rousing an inattentive or sleepy driver and will vibrate the steering wheel or the driver's seat, as though you had hit a rumble strip at the side of the road or had crossed "Botts dots," the round raised lane markers used on many roads. Safety engineers are still studying the most effective human interactions and alert systems, looking for ways to alert drivers without alarming them.

While driver feedback on LDWS is quite positive, they report that the systems can be confused by areas with complex lane markings or in construction zones, where the stripes have been repainted. Winding roads can also be a problem, but the systems can be switched off when drivers are perplexed.

Despite the occasional glitches, users like lane departure warnings, especially if they regularly drive long distances on highways. The European Union will make LDWS mandatory for trucks in 2013 and the U.S. Department of Transportation is asking for voluntary compliance on trucks heavier than 10,000 lb. gross weight. At least 12 commercial fleets in the U.S. are currently using LDWS and another 35 are testing them. LDWS is available on many premium cars today as well, including models from BMW, Buick, Cadillac, Infiniti, Lexus, Mercedes-Benz and Volvo.

What's Next for LDWS and Blind Spot Detection

The next step in the evolution of LDWS is to actually provide corrective action. Infiniti's system applies gentle braking if the car drifts out of a lane to give you additional time to react. The Lexus Lane Keeping Assist, currently available in Europe, literally steers the car for you, keeping it centered in the lane. It requires that your hands be on the wheel, however, and switches off if you remove them. It is anticipated that this type of technology will become available in U.S. cars as the technology matures and demand grows.

LDWS is still a complex, expensive technology. Integration with braking and steering drives up the price, so expect to pay a premium for it.

Blind spot detection systems, however, are relatively straightforward technology and should be available on many more models in the next several years.

Bio: Bill Machrone, a writer for Ziff Davis Media, is the former Editor in Chief of PC Magazine. He has written numerous articles about automotive technology topics, including onboard performance monitoring devices, automotive upgrades, remote camera/backup systems and sonar parking systems.