Rockleigh, N.J.
THIS is only a test, I tell myself.
So I floor the gas pedal, fighting the instinct to hit the brakes, and aim straight at Bob, who is standing directly in front of me here in a North Jersey parking lot.
Before the front bumper of the Volvo I’m driving kneecaps the poor guy, there’s a warning beep, a flash of red lights above the dashboard — and in an instant, a lurch, as the car comes to a stop. I never touched the brakes.
Bob, you’ll be relieved to know, is a test dummy and my target in the trial run of a new pedestrian-crash-prevention system to be introduced on the redesigned 2011 Volvo S60. The system is the latest development in what promises to be a new generation of safety systems that go beyond simply warning drivers of impending disasters — it actually takes control of the car to prevent them.
In 2008, 4,378 pedestrians were killed, and some 69,000 were injured, in traffic accidents in the United States, according to the National Highway Traffic Safety Administration. That has provided a strong incentive for researchers to explore ideas like warning systems, external air bags and softer crumple zones that might lessen the consequences of cars striking people.
But the possibility of having a car actually stop itself before hitting a person has been mostly in the realm of science fiction.
The new feature, which Volvo calls the Pedestrian Safety System, identifies pedestrians (and bike riders) in front of a vehicle using a video camera similar to those of lane-departure warning systems. The camera and its computer controls are from Mobileye, a maker of vision-based safety systems based in the Netherlands.
A video camera mounted near the rearview mirror is used to detect pedestrians.
The camera sits at the top edge of the windshield, in front of the rearview mirror. It scans up to 160 feet ahead with a 45-degree-wide viewing angle, enabling it to pick out as many as 64 people. Coupled with a radar unit mounted behind the grille that looks ahead as far as 650 feet (with a 60-degree field of view) and software fine-tuned over 330,000 miles of testing, the system assesses the collision probability based on the direction of the car and expected path of the pedestrians.
“But the camera is no better than the human eye,” said Adam Kopstein, manager of automotive safety and compliance for Volvo North America.
However, the system does have advantages over humans: the software uses sophisticated algorithms to judge whether a person is likely to jump in front of the car, based on the individual’s gait and position. Also, it does not suffer some of the blind spots — like windshield pillars — a driver must contend with.
Furthermore, the reflexes of its computer will best those of an inattentive driver. Indeed, that’s the system’s main function — to avoid pedestrian accidents caused by distractions.
A radar unit is mounted behind the grille.
In later attempts to ram Bob with the test vehicle, a specially outfitted Volvo XC60, the car rudely jammed on the brakes, throwing the passengers and myself against our seat belts.
“When it engages it is very harsh,” confirmed Geno Effler, a Volvo spokesman. “And it’s meant to be harsh.”
Volvo says the system can prevent a pedestrian collision at speeds of up to 15.5 miles an hour. That seemed a conservative estimate; as long as I kept the speed below 25 m.p.h., Bob remained unscathed.
Unlike Volvo’s complementary City Safety system, intended to prevent low-speed fender benders, the pedestrian avoidance system works all the time, even at highway speeds. So I pressed on.
At the highest speed I tried, nearly 35 m.p.h., the car attempted to stop, delivering a much gentler deceleration, but failed to bring the car to a halt before I tapped Bob. This action is known among researchers as accident mitigation; the car can’t defy physics and go from 70 m.p.h. to zero on a dime, but it will slow down to lessen the impact.
For those worried that leaving such emergency situations in the hands of a computer could prove disastrous, there are ways to override the system. One tester discovered that if the driver steps on the gas to accelerate just as the system begins to stop the car, the automatic braking will release (with the result that Bob ended up flat on his back on the pavement).
A Volvo spokesman explained that the system will also disengage should you swing the steering wheel left and right. Both features are intended to make sure the driver retains control if he is actively trying to avoid an accident — say, preventing a collision with another car while simultaneously swerving around a pedestrian.
There are limitations, of course. There is no automatic braking when backing up. Drivers in wooded areas worried about wandering deer will be disappointed to learn that the system recognizes only bipeds; engineers are working on animal recognition.
Furthermore, I am concerned that if automatic braking engaged in snowy or icy conditions at high speeds, it could create a situation more dangerous than the one it sought to avoid. (A Volvo spokesman was uncertain whether drivers would be able to deactivate the system in such conditions.)
Recalling Mr. Kopstein’s remarks about the camera’s limitations, it should be noted that once the sun goes down the system can see only as far as the car’s headlights. Unfortunately, according to the safety agency, 70 percent of pedestrian fatalities occur at night.
There are existing systems for such situations, like the night vision available on the BMW 7 Series. That infrared system can detect people in the dark three times farther than your headlights illuminate, according to Autoliv Electronics, the developer of the system. However, the BMW system only warns the driver; it will not brake the vehicle on its own.
Nevertheless, just as lane departure warning and adaptive cruise control systems have become more popular, it is likely that active safety systems similar to Volvo’s pedestrian collision avoidance will become common in the future. Mobileye, co-developer of the Volvo system, says it is working with more than a dozen companies, including BMW and General Motors, on similar safety systems.
No doubt there are unforeseen driving situations that will arise when thousands of drivers put these systems to the test in the real world. And our experience revealed that crashes in which drivers mistakenly stomp on the gas rather than the brake would not be prevented by the Volvo system.
“It’s not absolute prevention,” said Skip Kinford, chief executive of Mobileye. “There will be a learning curve.”
