Despite wobbling fuel prices, thickening waistlines and an avalanche of evidence lauding the benefits of active travel, Americans have been slow to embrace walking and cycling.
Research shows that walking has increased only slightly and cycling has stagnated during the past decade. Both activities have decreased among women, children and seniors.
Dr. John Pucher, a professor at Rutgers University in New Brunswick, New Jersey, said the increases have been among men, the employed, well-educated and people without a car.
"What struck me was the social inequity," said Pucher. "Most of the increase is in middle-aged men. That says we're doing something wrong in the United States."
He believes American resistance to active travel has more to do with safety concerns than suburban sprawl.
Pucher, who works at Rutgers' Edward J. Bloustein School of Planning and Public Policy, has been studying transportation and ways to make walking and cycling feasible for 15 years.
In a recent study he and his team analyzed government data on active travel from telephone interviews in 2001 and 2009 with tens of thousands of Americans.
He said data from 2009 shows that 25% of all trips in American cities are a mile or shorter, and 40% are two miles or shorter.
"Those distances are easily covered by walking and biking," Pucher said. "Children, women and seniors are just not going to cycle on a busy arterial street."
He said other studies have shown that women cyclists tend to make huge detours to get to safer facilities, even if it takes longer, whereas men are more likely to take the most direct route, even if it is a busy street.
Better sidewalks for pedestrians and separate and protected lanes for cyclists would encourage active travel among what he calls risk-averse groups.
"It's done all the time in Danish, Dutch and German cities," he said. "Some American suburbs don't have any sidewalks at all."
In residential neighborhoods, he said, traffic-calming measures such as narrowed streets and lowered speed limits would make roads less threatening to children, seniors and women.
Pucher cited northern Europe, where cyclists and walkers comprise a 50-50 mix of men and women as well as many seniors and children, as a good example.
"We also looked at earlier surveys that were not directly comparable," he said, "and we saw a continual decline in walking and cycling over two to three decades."
Danger, both real and perceived, is the main, and very fixable, reason walking and cycling levels are lagging in America, Pucher said.
"It's very clear how to do it, we just don't do it," he said. "Getting from point A to point B is a really daunting experience in many American cities because of such lousy pedestrian and cycling facilities."