Impossible! Photo by Thomas Hawk.

Has a civil engineer ever looked up at the Golden Gate Bridge and thought, “Nah, a suspension bridge could never work?” How many elected officials say, “our city could never be like San Francisco, so let’s not try to bridge our similar strait?”

We have plenty of working examples of bridges, and therefore we know we can build more. But when it comes to cities, the science of traffic engineering seems to deny their very existence.

The math seems simple. If you build new houses, stores or offices, they will generate a certain number of trips. Roads have set capacities. The added trips will therefore increase congestion and decrease Level of Service (LOS). To avoid congestion, many areas have Adequate Public Facilities ordinances requiring developers to widen the roads.

That’s a straightforward formula for adding suburban sprawl. It’s the system that built Tysons Corner. But strangely, when a plan comes up for building a real city, people balk. It could never work. It’d generate way too much traffic.

Yet the bridge is right in front of us. Downtown Washington, DC has that density. Somehow it does work. So do all the other similarly-sized cities, and the smaller cities. We used to build cities without worrying so much about adequate public facilities, and here they are. If your bridge model says that the Golden Gate would fall down, but it doesn’t, there’s something wrong with the model. If a traffic model says that a growing part of the region can never have densities like DC, it’s just as flawed.

And when elected officials balk at a proposal because of the flawed model, that’s a failure of imagination and a failure of leadership. Every time they say, “we’re not DC,” “we’re not Bethesda,” or “we’re not Reston,” it’s their vision that’s lacking. Where would we be today if Pierre L’Enfant said, “Washington could never be like Philadelphia,” and insisted on laying out a pattern of farms instead of a city? Why could we design cities in 1791 but not 2010?

The Montgomery County Council recently rejected a Planning Department proposal to relax the County’s Adequate Public Facilities law. The proposal would have let traffic models project a LOS of E instead of D as long as transit had LOS B — in other words, you don’t have to obsess quite as much over traffic if transit provides an adequate alternative. Yet they turned down the change, and did so unanimously.

Ben Ross of ACT criticized the APFO in a recent Gazette op-ed. Friends of White Flint point out some of the flaws: the White Flint plan adds more parallel roads next to Rockville Pike, creating a grid and moving more cars outside of the Pike; but if it slows down traffic on the Pike even while moving cars in other ways, it fails the AFPO traffic test. That forces County planners to widen intersections while still keeping the intersections pedestrian-friendly as the White Flint plan demands.

This plan still pales in comparison to the size of, say, NoMA, yet the builders of NoMA aren’t being forced to widen North Capitol Street to six lanes each way. Even though there is a whole city full of examples just to the south, Montgomery’s leaders can’t bring themselves to see past the restrictive rules.

Montgomery isn’t the only place missing a little vision. In Herndon, the Connection quoted Councilmember Connie Hutchinson preferring a lower-density vision for the town because she wanted streets widened. Plans suggested more housing, but she said, “Our traffic studies will show whether that’s feasible.”

If more housing isn’t feasible in Herndon, how could it have been feasible in Old Town Fairfax when that was built, or Arlington when Rosslyn-Ballston was built, or Washington, DC throughout its history? If the traffic studies say that all of these places with more housing aren’t “feasible,” then there’s got to be something wrong with the study methodology, not with the area itself.

Leaders across the region are grappling with growth. The suburban pattern of development is conservative and seemingly safe, it’s extremely expensive in infrastructure, harmful to water quality, tree canopy, and more, and most of all, increasingly less popular than walkable urban patterns.

Most leaders now agree that creating at least some new urban places in areas with existing infrastructure, like White Flint, Prince George’s Metro stations, or along the future Silver Line, is desirable. But fear and uncertainty from traffic modeling holds them back. Arlington didn’t let it stop them and now they’re a model for growth. DC became what it is today because we didn’t have those models at the time. It’s time for our leaders to trust their eyes instead of their computers and take the leap.