For the performance-minded driver, the new Porsche Panamera has it all, from a 400-horsepower V-8 engine to a digitally controlled suspension system that helps it corner like a racecar. But it also has a special feature you'll discover only if the car happens to run you down: a pop-up hood designed to save pedestrians.
Known as an “an active front lid,” the Porsche's hood is mounted on struts actuated by the same sensors that fire the car's airbags. At the moment of impact, the rear of the hood instantly rises, creating a steel ramp that can spell the difference between life and death. The tilted hood absorbs kinetic energy when a pedestrian strikes it, and also creates extra space above the solid engine block.
For automotive engineers, lowering the risks posed to pedestrians is one of the last great safe-driving frontiers.
Innovations such as airbags and seat belts have resulted in dramatically improved survival rates for people inside a car when it crashes.
But what about people on the outside? The recent deaths of 14 pedestrians in the Toronto area have shown how far there is to go, but car designers are working on the problem.
“There has been a phenomenal improvement compared to where we used to be,” said Tom Baloga, vice-president of engineering for BMW North America.
Like Porsche, BMW now includes pop-up hoods on its new models. BMW also offers advanced technology, such as a thermal-imaging system that detects pedestrians and flashes a warning, and computer-linked brakes that make sure a driver doesn't back off on the pedal during a panic stop (studies have shown that this a common driving fault).
“Even if you only take 10 feet out of the braking distance, it can make a difference,” Mr. Baloga said. “It might mean that the impact doesn't happen. And if it does, it will be at a lower speed.”
Engineers have spent years studying what happens when a vehicle hits a pedestrian, and have come to several conclusions about how to minimize injury. Some of them, unfortunately, conflict with other objectives, such as fuel economy, structural strength and repair costs. A flat, relatively soft front bumper, for example, minimizes the force of an impact, but hurts fuel economy. This type of design is also opposed by insurance companies, because it's more costly to repair.
Experts say many older vehicles are particularly dangerous to pedestrians. Jeffrey Muttart, a University of Massachusetts professor and vehicle safety guru, saw this firsthand back in the 1980s, when he worked as a police officer specializing in accident investigations. He recalled a case where a retired barber was hit by a vehicle with pop-up headlights as he crossed the street. What might have been a survivable accident with a car built to then-current safety standards became an instant fatality when the headlights severed both of the barber's legs.
“Nobody was thinking about what happened to pedestrians back then,” Prof. Muttart said. “Car design has come a long way.”
Engineers who have studied pedestrian collisions support the idea of safer vehicles, but warn that injury-reduction technology can only do so much. Mike Araszewski, an engineer with Intech Engineering in Surrey, B.C., said inattentive drivers emerge as the biggest problem in any analysis of pedestrian fatalities. He said studies have shown that drivers tune out background objects, including pedestrians, and notice them only if they move into what's known as a “hazard position” – such as when they step in front of a vehicle.
“You can make the cars safer,” he said. “But this is really about the drivers.”
