Night driving is dangerous - in fact it's more than three times more likely to end in a fatality than daytime driving, safety experts tell us.

Since the first autos crept out after sundown with their acetylene lamps glaring, automakers have looked for ways to make night driving safer.

Borrowing heavily from the military, both General Motors Corp.'s Cadillac Motor Car Div. and Ford Motor Co.'s Jaguar are ready to offer night-vision systems using infrared or other light-amplification technology in some 2000 model year cars.

Night vision conjures visions of James Bond, covert military exercises and surveillance technology at its finest. However, the idea of thermal imaging is nothing new to the military and has been used in some form for the past four decades. During the Gulf War, thermal-imaging systems helped U.S. military forces successfully carry out their missions under cover of darkness.

A version of night vision, known as NightDriver, also was in use in the Baja 1000 in November 1996, the first public demonstration of the system. NightDriver is Raytheon Systems Group's family of driving applications. NightSight (thermal imaging solutions) is the Raytheon brand name. The NightDriver system is based on the same thermal-imaging technology used by the military, detecting heat emitted from objects, giving users a new level of information useful for driving in hazardous conditions.

That same thermal-imaging night vision technology used in the Baja 1000 is now ready for everyday drivers. Cadillac will be the first automaker to offer a night vision system. It uses infrared technology and a "head-up display" (HUD) to alert nighttime drivers to potential danger that lurks well beyond headlight range. The system will be an option on the 2000 DeVille.

Night vision is not intended to be a drive-by system. The HUD projects a monochrome virtual image that appears to the driver as a superimposed brick-sized projection to the right of the driver's peripheral vision. The driver can view the normal road scene unobstructed by the virtual image, while still able to look at the virtual image without taking his or her eyes off of the road.

The system allows the driver to preview the road well beyond the headlights, making people and animals easy to spot due to their high thermal contrast with the background. Having the HUD image projected below the driver's line of sight helps the driver deal with headlamp glare from oncoming vehicles. The system also improves "visibility" in rain or snow.

Night vision incorporates four key technologies: an infrared sensor, optics, processing and head-up display. In the future, information from radar-based sensors could be added for collision-avoidance and blind-spot warning. But these enhancements are fairly expensive, and may not be necessary to help drivers see objects of interest down the road. Research into object recognition using contrast and edge enhancement also will continue.

Stuart Klapper, director of Automotive Programs at Raytheon Systems Group, says Texas Instruments began development of the night vision system for automotive applications 14 years ago.

In 1993 the Organized Crime Narcotics Task Force used the NightSight system developed by Texas Instruments in policing applications in Harris County, TX. The Task Force used the NightSight model 200 with 3601/2 visibility. Its display was a bit more cumbersome, using a dash-mounted separate screen like a television monitor, rather than the current system's HUD.

Craig Miller, a Task Force investigator, says the system "was great for detecting heat sources. It was a useful tool for law enforcement, but practicality prohibited its use on a regular basis. If there were a child lost in the woods, thermal imaging would be the ideal system to use to find that child," he says. But its use was limited in other applications such as for purposes of identification.

In July 1997 Raytheon acquired the Texas Instruments defense business, which included the NightSight technology. A Raytheon spokesman says the cost of a system in 1996 was about $10,000.

The Raytheon system selected for Cadillac uses infrared imaging with an uncooled focal plane array (UFPA) detector for the sensor and an active matrix liquid crystal display for the HUD. It differs from the old concept of thermal imaging that was based on quantum mechanics, which required cooling the sensor.

Raytheon developed the night vision sensor, while Delphi-Delco Electronics developed the HUD for the night-vision system.

The thermal-imaging sensor is placed behind the center of the front grille, a place that offers an unobstructed view of the road and where it can be kept reasonably clean by car washes. The sensor "sees" the world in grades of temperature rather than light, producing a picture that looks like a photographic negative, with highly contrasted blacks and whites.

Temperature-controlled for peak performance, the sensor is equipped with a window to protect the optics and an internal heater to prevent snow and ice buildup on the window. The system only operates at night, when headlamps are on and the Twilight Sentinel photocell indicates darkness.

The driver can control image position and intensity from a single switch that dims or brightens the display and tilt a mirror in the HUD, allowing the driver to move the image up or down, similar to adjustments for current HUD speedometer displays.

Normal visibility in an automobile at night is about 100 yards (91 m), but Mr. Klapper says peripheral information and visibility range is up to five times that - 500 yards (450 m) - which increases reaction time. He says Cadillac hopes to offer the system to consumers at the cost of a high-end stereo system. GM expects about 5% of DeVille buyers will order the system.

Cadillac is not the only automaker considering night vision. Jaguar is also working with Raytheon's European TI Systems to develop an image-intensification system that amplifies light, unlike the Cadillac system, which senses heat. The Jaguar system works in conventional high-beam lamps using near-infrared (NIR) illuminators and picks up low light visible by a 680x500-pixel charge-coupled device (CCD) monochrome digital camera. It enhances the road view that is within headlight range. The camera mounts above the driver's head to gather a nearly driver's-eye view of the road ahead.

Jon Harmon, manager of public affairs technology at Ford, says the Jaguar approach "is to make the information as intuitive to the driver as possible while maintaining the driver's comfort level with the system. This technology has a lot of promise for the future to be in a large range of vehicles as electronic technology becomes more refined."

The Cadillac system may have some advantages. It works in the far-infrared range and offers considerably more range beyond the headlights. Cadillac's system is passive, sensing temperature differences between objects in its view, which eliminates the need for separate illuminators. And because the infrared system detects only heat, ambient light or oncoming headlights do not induce glare in the HUD image.

Jaguar and Cadillac are both looking at significant costs initially, Mr. Harmon says, "but if the costs of electronics in recent years are indicators, cost should go down within a few years on both systems." A Ford spokesman hints that the price range for the Ford system will be comparable to the system in Cadillac's DeVille.

And what about Chrysler Corp.? A spokesman says it has no plans to institute such a system. "You can't just add features to vehicles and jack up the price," he says. "We're trying to direct the electronics industry to model nature, in that appendages serve more than just the one function. That is really the message of Convergence '98," which is scheduled for Oct. 19-21 in Dearborn, MI. - with Herb Shuldiner