What Does an Interstate Removal Study Look Like?

How does one go about removing a highway? Cities across the country are addressing possible highway removal and working to rebuild and reconnect their urban cores. In St. Louis that effort is being aggressively tackled by City to River. Every city is different: here, the new Mississippi River Bridge has made the conversation regarding highway removal possible. The ongoing Framing a Modern Masterpiece design competition has brought the issue to the fore as it attempts to address connectivity issues between the central city, Arch grounds and riverfront. While no two highways are identical, there are common threads to a successful effort.

First, a community must recognize the damage being done by a limited access urban highway and understand that connectivity, roads and access directly impact livability, economic vitality and are a community concern, not numbers on an engineer's spreadsheet or the imposed wish of distant commuters. That community must then speak out, challenge assumptions and ask others to join. From that core group of advocates, the message must reach the skeptics, those not inclined to move one way or another, and those who want more evidence.

The effort in New Orleans to remove I-70 has just received that evidence. Smart Mobility, a firm specializing in travel demand modeling and analysis of transportation systems, has produced a report entitled "Restoring Claiborne Avenue." The full report is below, but here are the chief findings as reported by the Congress for the New Urbanism:

  • A small fraction of drivers — less than 20 percent — use the Claiborne Expressway as a through route between the east and west portions of the region and beyond. With most through traffic using I-610, the Claiborne I-10’s “use does not match the intended function of an interstate highway,” concludes the report. 
  • The average trip length on the Claiborne Expressway is a mere 1.6 miles, according to the DOT’s regional model, suggesting many drivers use it as a short-cut between nearby neighborhoods. 
  • For the minority of users traveling the full length of the elevated expressway over  Claiborne, trips would lengthen by two to three minutes (off-peak and peak) under an alternative that would convert the freeway segment between Canal and St. Bernard to a boulevard, according to a review of the region’s travel-demand base model. Under an alternative involving removal of the freeway from Canal to Elysian Fields, travel times would lengthen by 3 to 6 minutes. 
  • For the larger number of users connecting to destinations such as Louis Armstrong Park, the French Quarter and downtown, connectivity would improve with a boulevard and improved street connections. 
  • Although a highly connected surface street network is a hallmark of the New Orleans system, street closures in the area over the years have actually reduced street connectivity. Removal of the Claiborne Expressway could be a catalyst to reconnect streets such as Galvez across the Pontchartrain Expressway, relieving Claiborne Avenue of its role as a primary connector between uptown and downtown. 
  • Traffic on both the Claiborne Expressway and nearby streets are substantially below pre-hurricane levels, “indicating that the capacity is available to absorb redistributed traffic” resulting from the freeway’s removal, say the study’s authors. 
  • The Claiborne Expressway is not a hurricane evacuation route designated for contra-flow traffic. It serves a role as a collector during times of evacuation but this function could be served better by a surface boulevard.