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Nissan's Brave New World of Auto Safety

Computer technology advances active safety

Computer technology is shaping the future of auto safety, according to Robert Yakushi director of Product Safety at Nissan North America. Government and industry in the past focused on passive safety features to reduce injury in an unavoidable crash. The seatbelt still remains the single most important safety feature in a vehicle, but occupants must buckle the belt for it to work and only 75 percent of Americans buckle-up. Auto safety in the future will rely on the quicker reflexes of computers to steer better, brake quicker, wake drowsy drivers and even keep vehicles in the middle of the driving lane.

Advanced Airbags

Advanced airbag systems in the Nissan Quest, Titan and Armada can detect an unbelted passenger, a child or a belted passenger and, using weight and seatbelt tension, deploy at varying degrees of speed, depending upon the passenger configurations the system has detected. The Nissan system employs a crash zone sensor, which allows for an early detection of the crash and a prediction of the crash severity.

Nissan's curtain airbags deploy along all seating positions when a rollover or side impact is detected. The Armada has a rollover sensing system that senses the roll rate and the angle and deploys the air bag accordingly. The system stays inflated from 6 to 10 seconds to prevent ejection of vehicle passengers during a rollover.

Preview Braking

Nissan introduced a new system called preview braking on the FX45, which uses a laser system to detect the relative speed between two vehicles and pre-pressurizes the brake at a certain point. When an emergency is detected, the typical human being takes about 100 milliseconds to decide that something is happening and then takes action after another 100 milliseconds delay. The brake assist system pre-pressurizes the brake system and gets the pads in contact with the rotor to cut out those critical milliseconds. That helps reduce braking distance by about 9 feet at 50 mph, which could avoid a crash or lessen the severity of the crash.

Driving well depends upon how well we process visual information—lights, other vehicles on the road, the lay of the road ahead, etc. What Nissan calls information safety is the ability of the driver to properly assess the environment around the vehicle. Coming in future Nissan models is a camera that monitors the driver for drowsiness or inattention and sets off sound alerts to get the driver's attention. It is currently under study at Nissan in Japan. One obstacle is varying facial patterns, and the need for the computer to be able to learn how to differentiate in order to properly respond. Wearing glasses can also confuse the camera/computer with glare.

Changing Lanes

NHTSA estimates that 58 percent of accidents are caused by lane departure. A system that warns the driver of lane departure could cut that accident figure. Nissan has a prototype system that is being developed using a camera system mounted in the rear view mirror to detect lane markings. It was introduced in Japan, but the lane markings there are very distinctive. "They are so distinct, I sometimes think there is somebody out there painting the lines every night," Yakushi said. In the U.S., lane markings vary from state to state and vary in upkeep. The system disregards lane departure warnings if the turn signal is activated. The next step is to override lane departure and bring the vehicle back into the lane without driver input. That system is also in use in Japan on one test vehicle. There are liability issues to be considered in this country—what if the driver decides to read a book and let the vehicle take over steering?

Smart Brakes

About 29 percent of collisions in Japan were rear end crashes, and that is about the same in the U.S. The intelligent brake assist, a step beyond Nissan's current brake assist, uses a laser system, which warns drivers that they are coming up on an object. If the driver doesn't respond, it will apply a half a g of brake, and will continue to do that if the driver still fails to respond. The next step is a system that will brake to a full stop, but that system in Yakushi's view is "way out there."

Tied in with the new brake technology is a pre-crash seatbelt. Nissan holds the basic patent, but is providing the license to competitors to promote safety technology. Seatbelts are retracted automatically when sudden braking is detected and/or the intelligent brake assist goes into action. The system is a motorized retractor that pulls the passenger back in the seat. Early restraint prepositions the occupant making the seatbelt and air bags systems more effective in a crash. By keeping the occupant firmly restrained, the system helps drivers maintain control of the vehicle in the same way that racecar drivers are strapped firmly into their vehicles to maximize driver control. It is being applied to the Q45 in the U.S.