Automotive innovators have tackled plenty of safety issues over the years from softening the impact of collisions to providing greater control during emergency braking. A satellite high above the Earth can pinpoint, within a matter of meters, the location of a stranded motorist.

Still, unless a driver turns his head at least 90 degrees, he cannot tell with any certainty whether a vehicle is in an adjacent lane. It surely contributes to road rage, as well as potential accidents. In one study, the National Highway Traffic Safety Admin. (NHTSA)estimates lane change and merging accidents account for 16% of all major collisions.

Today, suppliers are pursuing numerous technologies to eliminate the pesky blind-spot, from more easily adaptable aspheric side mirrors to advanced - and more expensive - cameras and sensors designed to detect any object behind or beside a moving vehicle.

The technologies are not terribly new, but they have been refined over the years - and costs are coming down. In addition, NHTSA, which allows only passenger side mirrors to be convex or aspheric, now considers allowing aspheric mirrors on the driver side.

Convex mirrors are bent, making objects appear smaller and farther away. Aspheric mirrors are flat, but the outer edge is angled outward. Both mirrors significantly expand a driver's field of vision. Convex mirrors cost slightly more than flat ones, while aspheric mirrors can be several times more expensive, depending on the curvature.

A Dutch research group is preparing a report for NHTSA, due this June, on how European drivers interact with aspheric and convex mirrors, which are used on both sides of vehicles in that region, says Stephen Kratzke, director of NHTSA's Office of Crash Avoidance Standards.

"If we get information that they (aspheric mirrors) will work, then we would allow them," Mr. Kratzke says. "We want to know if people will catch on quickly to how you use them to expand your field of view."

NHTSA doesn't take this stuff lightly. The agency currently requires that driver-side mirrors be flat, partially because motorists complained of headaches when NHTSA first allowed convex passenger-side mirrors in 1983. Mr. Kratzke says it's been a long time since NHTSA heard such complaints.

Suppliers are not counting solely on aspheric mirrors as the future in rear-vision automotive applications in the U.S. Many are investing in sensors and digital camera technology to tell a driver whether an adjacent lane is clear.

Donnelly Corp., which makes 95% of the prismatic mirrors used on U.S. cars today, is delivering a three-camera "panoramic vision" system to replace the mirrors in a concept vehicle being produced by a customer within the next year.

The system replaces the side mirrors with tiny digital cameras, about the size of a golf ball, and adds a third camera in the rear of the vehicle. All three images are converged into one, which can be displayed for the driver on a screen on the instrument panel.

The system provides full vision of everything behind and beside a moving vehicle. It nullifies the need to turn your head, for those people who don't trust mirrors.

Donnelly developed the system with Vision Group plc, its partner in Edinburgh, Scotland. Vision Group provides the CMOS imaging chip driving the system.

Are drivers ready for it? "We have the functionality," says Ken Schofield, Don-nelly's executive director of advanced engineering. "The question is price and application. It requires a change on the part of drivers."

If NHTSA struggled with convex mirrors, it surely will view camera vision with extreme caution because of the potential distractions for drivers.

"Camera vision is like having a TV on, to the extent that it's taking the driver's attention off the road," Mr. Kratzke says. Still, he concedes, drivers already are looking at mirrors in three different places. Combining the images into one central location could be an improvement.

But government acceptance isn't the only hurdle. Cost is a major consideration. Mr. Scho-field estimates the pricetag could be $1,000, going down to $350. Eventually, costs could be comparable to existing mirrors, depending on the features and configurations.

"It's just too expensive," says Ken LaGrand, executive vice president for mirror supplier Gentex Corp., which is developing rear-vision systems with its partner, Photobit Corp. of Pasadena, CA. "As a consumer, I would like it on my vehicle, but my feeling is it's probably got to come down in price to a few hundred dollars. That might be a little optimistic," he adds.

Mr. LaGrand says it will be several years before a U.S. vehicle is equipped with rear-vision cameras. Meantime, Gentex is pursuing aspheric mirrors, which started out in Scandinavia 10 years ago and are expected to outnumber flat and convex mirrors in Europe within the next few years.

Gentex recently announced it will supply the world's first aspheric exterior electro-chromic, or automatic-dimming, mirrors for several Mercedes-Benz luxury sedans.

Another method of eliminating blindspots is with sensors that beep to warn drivers that the lane they are moving into is occupied. Several suppliers, including Donnelly and Gentex, are developing such systems.

Autosense Ltd. of Denver, CO, has teamed with Siemens Components Inc. to develop SideMinder, which uses sensors located near the rear taillights to alert a driver, with a flashing warning light, if a vehicle is in the right or left blindspot.

Alirt Advanced Technology Products, a small Canadian company, is planning commercial delivery of a battery-operated aftermarket blindspot sensor this year.