In centralized cities like New York City and Chicago, transit is thriving and walking and bicycling levels are significantly higher than in other cities and towns across the United States.

This should come as no surprise. After all, walking and transit are a complementary pair. The two go hand in hand. In centralized metropolitan areas, walking conditions are generally more favorable. It's simply easier to reach the bus stop on foot or by bicycle.

But in a country whose growth is dominated by suburban sprawl, providing reliable and efficient transit service is a real challenge. Although most walking and bike trips are one or two miles long, although the suburbs feel the crush of traffic congestion perhaps most painfully, areas like these do not have the necessary population density to support good transit.

So is there a way out of the transit Catch-22? Why, sure there is. By successfully combining transit with bicycling and walking, we create great potential for reduced car trips� provided people can realistically walk and bicycle to the transit service.

It's already happening in places like Amsterdam, Zurich, and Copenhagen, where a quarter to one half of all trips are made by bicycle. And the early success of the Caltrain rail in the San Francisco Bay area is paving the way for the effective combination of bicycling and walking access to public transit.

But before this kind of success spreads to the smaller cities and suburbs of America, we've got a few stops to make. We've got to consider special transit concerns of women and issues pertaining to the disabled. We need to take a closer look at successful transit models before walking to the transit stop becomes a realistic option for the public at large.