Softening the punch of motor vehicles when they hit a pedestrian or cyclist is the next step in automotive safety, but U.S. pedestrians will benefit as an afterthought. This fall regulators in Europe will require that all new vehicles sold in Europe pass crash testing designed to mitigate head and leg injuries in accidents with pedestrians or bicyclists.
In 2010, much stricter regulations will go into effect. U.S. pedestrians can expect the initial pedestrian-friendly designs to carry over to this market; but, in the absence of comparable U.S. regulations, the more sophisticated pedestrian-friendly technology geared to meet Europe's 2010 regulations may not be packed under U.S. hoods.
Statistics.
Pedestrian deaths in other parts of the world are a bigger problem than in the States. In India, more than 40 percent of traffic fatalities involve pedestrians. Each year 8,000 European pedestrians are killed and 300,000 injured. In the U.S., 5,000 are killed and 70,000 injured each year.
When a pedestrian is hit by a car, their legs are knocked out from under them and the upper body is thrown down-very hard-onto the hood of the car. Today's cars are aerodynamically designed to glean extra miles per gallon. A consequence of this fuel-efficient design is minimal space between the outer body panels and the hard structural components. Serious or fatal head injuries often result because just below the hood, in most cars, is a heavy, rigid engine. In almost all collisions, the pedestrian falls onto the road after the accident has occurred. The exact influence of this on the seriousness of the injury has not been fully investigated, but modifications to the vehicle cannot overcome this aspect of pedestrian accidents.
Soften the Blow.
Automakers are focusing on two areas in pedestrian safety: The first step is absorbing impact in a collision, and the more sophisticated second step will be avoiding the accident altogether.
Honda has been in the lead in pedestrian safety, developing the first pedestrian crash test dummy, Polar II, to measure the dynamics of car-pedestrian accidents. The dummy mimics the performance of the human leg, chest, and shoulders in a collision with a car. Utilizing feedback from the dummy, the 2001 Civic was designed with a 3-inch gap between the hood and engine block to cushion impact and bendable hinges that allow the hood to collapse more easily.
Mazda redesigned the hood of its RX-8 with pedestrians in mind. Instead of being made of a flat sheet of steel with a few widely spaced supports, the RX-8's aluminum hood has a deeply dimpled structure underneath, designed specifically to provide extra cushion.
These hood systems would not work with SUVs because the head impact would be at the front of the hood. SUVs are more likely to employ passive protection like eliminating sharp edges, and softening front ends. For instance, rhino bars have virtually disappeared from European SUVs.
Outer Airbags.
Researchers at the Ford's German center, in collaboration with the Cranfield Impact Centre in England, developed a family of pedestrian computer models to test vehicle/pedestrian crashes. The family includes a six-year-old child, a small female, an average and an above average sized man. Based on this research, Ford is developing two air bags designed to protect pedestrians during an impact.
An over-the-hood airbag deploys from just above the bumper. Activated before impact by a pre-crash sensor, it inflates in 50-75 milliseconds to a 54-inch wide and 22-inch high pillow covering the headlights, the top of the bumper and several inches above the hood. The grill and hood areas are a source of abdominal and hip injuries for medium or large adults, and chest and head injuries for smaller stature adults or children. A second airbag design offers head protection when the pedestrian is thrown over the hood toward the base of the windshield.
The system consists of two air bags triggered when a sensor detects the pedestrian's initial impact with the bumper. The airbags deploy in the time it takes the pedestrian to travel across the hood area toward the windshield-about 100 milliseconds. When fully inflated, the two airbags cover the full width of the vehicle along the windshield base, from A-pillar to A-pillar. This covers the critical "hard points", such as the windshield wiper spindles and hood mounts, as well as the base of the windshield glass. However, the bag does not completely block the driver's view. The latter airbag is closer to production because it does not require sophisticated pre-impact detection.
Newer Technology.
Still in development to meet stricter regulations in 2010 are driver assistance technologies that would alert drivers to pedestrians in their path and apply braking quicker than is humanly possible. For instance, Mazda is testing laser radar that can detect pedestrians 50 yards in front of the vehicle. The system sets off a warning bell and dashboard light to alert the driver and applies the brakes if the system detects an imminent collision. A strip of fiber-optic detectors spanning the front bumper can tell whether the vehicle has struck a person and then deploys a bumper airbag to minimize leg injury and at the same time raises the hood slightly up and straight back, providing a few crucial inches of extra cushioning above the engine. Airbags housed at the base of the windshield also instantly inflate, providing a protective cushion over the wiper blades and windshield.
Honda's pedestrian-sensing night vision technology will be an option this year on the Honda Legend luxury sedan sold in Japan. The infrared system identifies pedestrians from an indistinct blur of dark images, wraps them in an orange frame and displays the image on a 3x8-inch color display screen that pops up above the instrument cluster and sounds a warning.
Pedestrian safety is a major challenge since additional safety systems also increase vehicle weight and raise fuel consumption and exhaust emissions. Protective measures can also influence design and European niche makers like Morgan and Lotus argue that the design adjustments needed to meet the regulations will destroy their distinctive looks and the additional costs will run them out of the market. That remains to be seen.
