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