Connectivity barriers: When is it worth breaking them?

Portland's Reedway Street at the Union
Pacific railroad. Try crossing this! Actually,
don't. Image: author.

Why did the chicken cross the road? You know the rest. But what if that road is a 16-lane freeway, or the busiest railroad in the state? Or, what if it is a natural “road” – a river, gulch, canyon, arroyo, cliff or hillside?  To get to the other side, the chicken would need to somehow avoid dismemberment or drowning. More probable is that our feathered friend would stay on its side of the road, or take a circuitous route that increases the length and time of its trip by a large factor. As such, the chicken may be encouraged to get in its chicken car and drive two miles to a destination that is really just 200 feet away for a more flight-capable bird.

Transportation facilities – linear features intended to provide mobility – sometimes reduce it instead. Much has been written about mid-century freeways severing urban neighborhoods that, due to their disenfranchised minority populations and blighted housing stock, were deemed disposable. And most Americans have heard the expression that someone “grew up on the wrong side of the tracks.” While we have enjoyed the economic benefits of freeways and railroads, they came with a steep social price that we are still paying today.


Sometimes, if a community gets sufficiently annoyed about the gulf separating them from where they want to go, they organize and ask their leaders for a crossing. If they’re lucky, someone listens, finds a few million bucks, and gets it built.

This presents a series of policy questions. When is it worth spending millions to connect two sides of a freeway, railroad or river with a grade-separated crossing? What are the density thresholds or other criteria that make it worthwhile? How far apart should these crossings be spaced in urban, suburban and rural contexts? Should a new crossing be just for people on foot or bike, or should it be a complete street, or even a new interchange? How about just peds, bikes and emergency vehicles? Conversely, when is it okay to say, “No, you people don’t need to get from point A to point B in any sort of direct fashion”?

The answer is usually, “It depends.” But that’s not very helpful. Short of a doctoral thesis project, we can at least take an anecdotal look at how transportation planners have responded to these questions in practice.


Think of a freeway that passes through different parts of a major American city. Downtown, you’ll often see an overpass or underpass at every street – I think of the Vine Street Expressway in center city Philadelphia or Interstate 5 in downtown Seattle. In the first ring of pre-World War II neighborhoods, you may have a freeway crossing every quarter to half mile, some including interchanges. This is the case in most Chicago neighborhoods outside The Loop, and in north Portland along Interstate 5. In the suburbs, crossings may be limited to freeway interchanges spaced one to two miles apart or more. In rural areas, the barriers created by interstate highways have necessitated 20th century inventions like frontage roads and ranch exits.

Darlene Hooley Pedestrian Bridge at Gibbs Street.
Image: galvanizeit.org

Where mid-century highway builders created significant hardships, later planners have occasionally mitigated matters. Portland last year finished the $6.7 million Darlene Hooley Pedestrian Bridge at Gibbs Street, connecting two southwest Portland neighborhoods that had been sliced and diced by decades of highway infrastructure. Tacoma’s ongoing revitalization has been aided by the 2001 Chihuly “Bridge of Glass,” spanning six lanes of Interstate 705 and three main line railroad tracks to connect downtown with the waterfront and namesake glass museum. And we can’t forget Boston’s “Big Dig,” which despite its infamous cost and schedule overruns, managed to completely eliminate an egregious connectivity barrier and provide acres of new parkland.

New river crossings are less common. Portland is building an entirely new span over the Willamette River just for light rail trains, buses, bicyclists and pedestrians. When the bridge opens in 2015, downtown Portland will have nine river bridges over the course of three miles. But to the south in suburban Clackamas County, there are no bridges over the Willamette River for nearly nine miles. We’re not talking about the Amazon Delta here – the Willamette is in several places just 400 feet across. Significant towns and neighborhoods line the shores, apparently content to be isolated from one another. This issue is not nearly as severe in other riverine metro areas like Pittsburgh and Minneapolis/St. Paul. Eugene, Oregon has seven ped/bike bridges to supplement its four road bridges over the Willamette River, which in this stretch is similar in width to the Clackamas County segment.

So why build ped/bike crossings? Can’t people just get in a car and drive around the offending barrier, or find somewhere else to go? Sadly, that is the mindset in some places. But beyond the obvious equity arguments about people who can't afford cars, I would posit that any effort that gives walking and bicycling an edge over driving, but does not worsen operational conditions for vehicles, is a good thing. Awarding pedestrians and bicyclists a connectivity advantage by means of a bridge is one way to incentivize active transportation. If the distance between point A and point B is all of the sudden reduced from five miles to one quarter mile, you have potentially moved a whole set of trips from car to ped/bike. Furthermore, connectivity projects like ped/bike overcrossings are typically less controversial than projects that reduce vehicle capacity (like road diets), and they’re often cheaper than building a full-on road bridge or adding bike lanes and sidewalks to an existing bridge.

For six years I have been pitching a potential ped/bike overcrossing project to city officials and neighborhood leaders: connecting two stubs of Reedway Street over Highway 99E and the Union Pacific railroad in southeast Portland. Support for the idea has ebbed and flowed over the years, most recently cresting when Portland-Milwaukie Light Rail planners proposed a station here. Ultimately, the Harold Street station was mothballed due to a combination of federal budget cuts, travel time concerns, alleged sub-par density, and - here's the Catch 22 - a need to build a ped/bike overcrossing. But despite the death (or dormancy) of the Harold Street station, I think the crossing is still a great idea.

Mapping geekery: distance between crossings.

With the aid of Google Maps, I discovered that the east side of Portland has an average spacing between railroad or freeway crossings of about a third of a mile. But here at Reedway Street, the nearest crossings are separated by over a mile. The crossing to the north, Holgate Boulevard, is a high-speed four-lane viaduct with narrow sidewalks obstructed by light poles and utility boxes. This prevents me and my neighbors from safely and conveniently walking or bicycling to destinations on the east side of the railroad, such as Reed College, two very nice parks, and several industrial employers (one of which happens to be a fantastic microbrewery). Similarly, the "Reedies" and other folks on the east side of the tracks are hampered from directly accessing services in my neighborhood, including a grocery store, restaurants and medical offices. But that hasn't stopped people from trying - several years ago a transient was hit and killed by a train while trying to cross the tracks at Reedway Street.

Building a ped/bike overcrossing would solve these problems. But it’s a mere speck in America’s 23rd largest metro area, in a nation where even basic infrastructure maintenance needs are going unmet. Similar connectivity challenges exist in Los Angeles, Omaha, Philadelphia, Miami, and pretty much anywhere else that has a transportation network. Who knows if anything will come of my crossing proposal, or the tireless efforts of countless other advocates for similar projects around the country. But someone has to call attention to these frustrating, sometimes lethal barriers to connectivity, or else we will remain a disjointed world where chickens want to cross the road but end up as ground meat.