If more commuters are setting their alarm clocks to beat the morning rush, others seem to be sleeping in. Commuting between the hours of 9 and 11 a.m. also has increased significantly. Pisarski's findings, published recently in the book "Commuting in America III," are more evidence of a phenomenon that many drivers already know all too well: "Rush hour" as we know it is dead. That's not true everywhere. But in the most traffic-clogged regions, the notion of distinct periods of congestion in the morning and afternoon has morphed into heavy traffic from before sunrise until after sunset. Call it "rush day."
If that sounds awful, the consequences aren't entirely bad. Rush-day traffic means that additional capacity is being squeezed out of the existing transportation network. That's possible only because commuters are very adaptable and will sometimes go to amazing lengths to avoid getting stuck in traffic. Pisarski says he hears more and more stories of road warriors arriving at the office by 6 a.m., then catching an hour of winks in their parked cars before heading inside to work. "The genus 'Commuter Americanus' is a very resilient creature," Pisarski says, "but we're pushing them beyond the range of their flexibility."
There are other factors fueling the rush-day phenomenon. Beltways that were initially conceived as express routes for through traffic have become suburban arteries serving office parks and shopping centers. Homebuyers searching for sizable but affordable homes are pushing farther and farther into the exurbs. Technology and telecommuting are also starting to affect work and travel patterns. Pisarski found that more workers now telecommute than walk to work. "In some cases, they will work at home in the morning, avoiding that long commute, but then get on the highway and drive to work at 10," says Tim Lomax, a congestion expert with the Texas Transportation Institute.
The emergence of rush day bends traditional ways of thinking about transportation infrastructure. Planners are trained to design road networks and transit schedules around peak-hour trips. As commuting patterns become more diffuse, however, that's becoming harder to do. "It's not as tidy as it used to be," says Robert Cervero, a planning professor at the University of California, Berkeley. "It's getting more difficult to model commuting patterns and use that as a platform to predict the future."
Those patterns may become less predictable. The reason why planners weigh commuting data so heavily is because trips to work account for a large number of overall trips. But as baby boomers retire, a huge demographic bubble of nine-to-fivers will start moving around more in the middle of the day.
And the change is coming sooner, rather than later. In the Atlanta region, for example, one-third of the people over the age of 60 fall between the ages of 60 and 64. In other words, the retirement wave is upon us. "There's an enormous shift about to happen in standard circulation patterns," says Scott Ball, an Atlanta-based community design consultant. "But no one is doing well at surveying the transportation needs of seniors."
