Graying of U.S. drivers

A coming surge in the number of older women driving. A steep decline in the percentage of people who walk to work. An embrace of carpooling by Hispanics. A sharp increase in the portion of black households that own cars.

These are the key findings of the most exhaustive study of Americans' driving habits in the past 10 years, cited in a report released today by the Transportation Research Board, an arm of the National Research Council.

In "Commuting in America III," Virginia transportation expert Alan Pisarski examined Census data from 1990-2004 more than 2 1/2 years. Pisarski also published "Commuting in America" reports in 1987 and 1996.

Among his findings:

• The number of older female drivers will increase dramatically as baby boomers continue to work past age 65. Currently, 75 percent of women over 55 have drivers' licenses, but 90 percent of women under 55 drive. As the percentage of the population over 65 rises sharply after 2010, a key question will be how many continue to work — and commute.

"Retired (people) tend to be very careful drivers — no freeways, no after-dark driving," Pisarski says. "But if you're working, you don't have that choice. That's a safety question we'll have to address."

• The percentage of Americans who walk to work dropped from 5.6 percent in 1980 to 3.9 percent in 1990 and 2.9 percent in 2000.

"(Walking has) been replaced by transit, been replaced by the automobile," Pisarski says. "If you think of the number of jobs one can get to walking, no matter where you live, it's very limited. But if you add a 10-minute commute time, you multiply many times over the number of jobs available."

John Norquist, president of the Chicago-based Congress for the New Urbanism, which promotes the development of communities where jobs and stores are close to housing, predicts that the decline of walking will slow.

Norquist says that while developers increasingly are building homes in mixed-use, "live-work-play" neighborhoods and getting premium prices for them, "most of the stuff that's built is still in the sprawl form. (But) I think we will see a dramatic effect on the walking numbers five years from now."

• Hispanics carpool at a rate double that for non-Hispanics — 23 percent vs. 11 percent. "It's an extraordinary phenomenon," Pisarski says. "These might be car pools of four, five or six people. It tends to be very early morning starts. It may be a cultural thing, where you tend to know your neighbor, or it might be out of necessity."

• The "most significant trend regarding auto ownership" is the sharp drop in the percentage of African-American households without vehicles, from 31 percent in 1990 to about 24 percent in 2000.

• Commute times are getting longer. The percentage of workers who reach their jobs in less than 20 minutes dropped to 47 percent in 2000 after hovering around 50 percent for decades. Commutes in 40 states increased two to four minutes; Kansas was the only state with an increase of less than two minutes. Georgia and West Virginia led all states with increases of five minutes or more.