Occupants of a car are protected by seat belts, airbags and dashboards devoid of sharp objects. A pedestrian's only defense generally is to get out of the way.
More than 4,000 people are killed and 70,000 injured each year in the United States when hit by cars. Typically they're struck in the legs and thrown onto the hood. Their bodies slide until their heads smash into the windshield-wiper arms, the windshields or both.
With U.S. regulators considering rules or incentives to make pedestrian accidents more survivable, Honda and Volvo have led automakers making design changes that bring safety advances to the outside of vehicles.
They include breakaway wipers, hoods with space between them and engines to absorb impact energy, and exterior airbags designed to keep a pedestrian's head from hitting the windshield.
"A pedestrian that's hit by a car, it doesn't have to be a death sentence," said Jacqueline Gillan, president of Advocates for Highway and Auto Safety.
The number of pedestrians killed in U.S. traffic crashes declined from 4,892 in 2005 to 4,109 in 2009 before rising again to 4,432 in 2011, the most recent year available from the National Highway Traffic Safety Administration. Fourteen percent of people killed in crashes that year were pedestrians.
In Japan, pedestrian deaths are about a third of traffic fatalities. That led Honda, based in Tokyo, to make design changes to vehicles that it has brought to the U.S., said Doug Longhitano, a U.S.-based Honda safety research manager.
Fenders on Honda or Acura models sold in the U.S. are offset from the frame, as are hoods from engines, to provide some limited cushion if a pedestrian is hit. Windshield wipers are designed to break away so they don't gouge or gore a person on impact, Longhitano said.
Those design changes have been standard on Honda and Acura vehicles sold in the U.S. since 2008.
Volvo, the Swedish carmaker owned by China's Zhejiang Geely Holding, introduced the windshield airbag as standard equipment on its V40, which isn't available in the U.S., for the 2013 model year, said Laura Venezia, a U.S.-based spokeswoman.
General Motors include space between the hood and engine to provide a buffer, said Heather Rosenker, a spokeswoman for the Detroit-based company.
Auto regulators are working on global pedestrian safety standards that could be adopted into a U.S. regulation, NHTSA Administrator David Strickland said, declining to give a timeline.
"It's a two-step process, but traditionally speaking, those global technical regulations are very close to what will ultimately result in a final regulation here in the United States," he said.
If regulators include pedestrian safety in their safety- rating system, they could choose to give an incentive to vehicles that perform well in crash tests or that include particular technologies or designs, Strickland said.
While they may also save lives of bicyclists, the studies and automaker design changes are specific to collisions with pedestrians.
Europe first set pedestrian-protection requirements in 2003. Last December, it added more stringent requirements for how vehicles perform in pedestrian crash tests for the bumper, hood and its edge and windshield.
The European Union has even stricter performance requirements set to take effect in 2015.
Japanese automakers changed hood designs to comply with required tests in that country for pedestrian head injury.
In the U.S., most research and government work has focused on preventing car-pedestrian crashes, rather than lessening their severity.
In January, NHTSA proposed a rule requiring electric and hybrid-electric cars to emit sounds to warn and protect bicyclists and pedestrians, particularly the visually impaired.
NHTSA said in April that it might evaluate pedestrian protection in the next revision to its five-star safety rating system, known as the New Car Assessment Program, or NCAP. Car buyers consult the agency's ratings, which help influence vehicle purchases.
Encouraging pedestrian-related design changes by offering higher safety ratings, instead of requiring them, would be the same approach NHTSA is using to induce automakers to install backup cameras throughout their fleets.
Even that approach would be too much for the Alliance of Automotive Manufacturers, a trade group whose members include American, Japanese and European automakers. Honda isn't a member.
"This is a really complex issue, and we believe it's best to address this through a universal, worldwide regulation before we consider adding this to NCAP," said Wade Newton, a spokesman for the Washington-based group.
Customers don't have much motivation to pay for pedestrian protection if it's sold as an option, said Jessica Caldwell, an analyst with auto-researcher Edmunds.com in Santa Monica, Calif.
"People are reluctant to pay for safety features that would benefit them or the other people inside the car," she said. "I don't think the willingness necessarily is there. Perhaps if it's packaged with other safety features more tangible with the consumer."