At a crossroads: Complete streets and functional classification

By Mary Ebeling
As the demand for more complete, multimodal streets increases, so does the push to alter the functional classification system to allow for greater local flexibility in roadway design.  Principal arterial roadways commonly run through the heart of downtowns, and often serve as the main street in the business district. The functional classification system, not revised since 1989, restricts communities seeking flexibility in roadway design and can effectively hobble transit planners attempting to advance livability initiatives supported by the residents of the cities where they work. This is particularly true for urbanizing suburban areas as well as for cities and urban centers that seek to transition neighborhood and urban streets into a complete-street model.
Because the current system forces federal aid arterial roadways into one of two boxes—urban or rural— the system is unable to respond to the needs of communities that are actually neither of the two. Available categories do not capture the context for arterials in a metropolitan region that are not part of the urban core, but are also not rural. These roadways then default to “suburban” standards, which prioritize automobile throughput at the expense of creating a walkable, multimodal corridor through the community. Essentially, the system fails to allow communities that are not quite urban, but wish to create a policy supporting walkable and bikeable streets, the flexibility to design a complete-street arterial that prioritizes other modes as well as single occupancy vehicles.
Compounding the concern over the functional classifications and restrictions on a community’s ability to develop complete streets, MAP-21 expands the National Highway System to include principal arterials. Many roads now captured under the NHS have segments that serve as local main streets or other local links that would be amenable to bike and pedestrian facilities, perhaps through narrowing motor vehicle lanes. The NHS classification, however, may limit a community’s ability to make context-sensitive infrastructure improvements that increase multimodalism, livability, and generate local economic benefits. States such as Vermont have put forward proposals for a functional classification system for multimodal corridor planning.
Changes to how roads are classified under MAP-21 have drawn renewed attention to design standards. The transportation bill reclassifies principal arterials into the NHS, which mandates high-capacity roads and limits a community’s flexibility. While state DOTs and communities managing these roadways can always petition to reclassify the street, this action solves the problem for a single roadway but does not address the overall system need. The more proactive approach is to work to implement a revision to the functional classification system.
Mary Ebeling is a Transportation Policy Analyst at SSTI.