It sounds simple and appealing. Your city has a major road with a lot of traffic, but city planners and citizens want to make it more pedestrian-friendly, encouraging more walkable stores in place of purely big box strip development. How about pedestrian overpasses? With a walkway, people can cross in complete safety and not interfere with the existing traffic. You can even build new stores with entrances on the second level, so that people can walk directly from stores on one side of the street to the other. What could be wrong with that?

Vision of the future from GM’s “To New

Horizons” exhibit at the 1969 World’s


A lot, actually. This was a topic of discussion and disagreement at Wednesday’s Rockville Pike community meeting. One member of our table, a former urban planner, felt very strongly that new development should not impede the existing traffic, and heavily used at-grade crosswalks would indeed slow down traffic. The solution, he argued, was a system of pedestrian overpasses.

But skybridges connecting retail above the street simply don’t work, and many cities are actually removing the ones they built in the 1970s. Elevated walkways as an urban design (or even suburban design) element are one of those 1960s ideas that, like ubiquitous freeways criss-crossing the city center and single-use zoning, we now realize to be detrimental to a well-functioning city. In fact, elevated sidewalks were one of the centerpieces of the “To New Horizons” film by General Motors at the 1939 World’s Fair that inspired a generation of Americans toward a shiny future that ended up destroying their cities. (Fast forward to about 20 minutes in to hear about the skybridges.)

Freeways, skybridges follow a similar principle: we should separate uses. “Put the people with the people. Put the business with the business. Put the industry with the industry.” Separate the cars from the people so the cars can go fast and the people stay safe. But as we now know thanks to Jane Jacobs and others, separation is dangerous. Separation means there are fewer “eyes on the street” in any one place. Pedestrian overpasses in Minneapolis make the sidewalks more dangerous. Overpasses themselves can be dangerous, keeping people enclosed in a small space that may be empty much of the day and an appealing spot for crime.

Skybridges also foster less public investment in the street. After all, if people are supposed to cross upstairs, we don’t need those crosswalks any more. Maybe we can get rid of this light. How about an extra turn lane in front of this new complex? Wouldn’t traffic move better with a flyover ramp in addition to the walkway? And before you know it, the street that was formerly a suburban arterial has practically turned into a freeway—the exact opposite of the boulevard citizens want. Once you take away pedestrians, there’s no reason to engineer what remains for pedestrians, and the cycle of auto dependency gets deeper.

That’s particularly bad because people often don’t use skybridges even when they are there. Pedestrians generally don’t want to climb two flights of stairs on each end just to cross a street; they will take the shortest path. When leaving the meeting, I crossed the Pike at Bouic Avenue, where there is no crosswalk, instead of trekking a whole (long) block north, out of my way, to Halpine Road which is farther from the Metro. After all, I only had to cross three lanes, then wait at the island, and cross three more.

A 1960s city planner would say that means we need a fence to keep pedestrians off the street. A 21st century city planner would say that means we need a crosswalk, a traffic light, and a better pedestrian refuge in the median. People will walk across the street whether there are elevated walkways or not. The best thing we can do is design the street for it, balancing the pedestrians with the traffic so neither is unduly inconvenienced.

Right now, Salt Lake City is grappling with a proposed skybridge across Main Street. Denver’s are almost completely deserted and many are neglected. Des Moines’ Skywalk has caused 60 percent ground-floor retail vacancy rates. As Rockville tries to make its Pike into a low-density urban environment, similar to the density of some of the mid-size Midwestern and Mountain West cities, it should turn away from GM’s 1939 vision and toward true new horizons without skybridges.

David Alpert is Founder and President of Greater Greater Washington and Executive Director of DC Sustainable Transportation (DCST). He worked as a Product Manager for Google for six years and has lived in the Boston, San Francisco, and New York metro areas in addition to Washington, DC. He lives with his wife and two children in Dupont Circle. Unless otherwise noted, opinions in his GGWash posts are his and not the official views of GGWash or DCST.