A major barrier to human-scale, complete streets appears ready to fall. The Federal Highway Administration (FHWA) is proposing to drop 11 of 13 mandatory standards for streets under 50 miles per hour, which will help in the design of federally owned urban streets.
“It is definitely a step in the right direction that FHWA is finally responding to the overwhelming amount of research showing little safety benefit to most of their controlling criteria,” says Wes Marshall, associate professor in the Department of Civil Engineering at the University of Colorado.
Wider lane width is one of the crucial criteria for urban streets that has been shown to have no safety benefit. A series of studies (link, link) have shown that in urban places 12-foot lanes—which have been used on arterial streets since the middle of the 20th century, are less safe than narrower lanes because they encourage speeding. For comparison, Interstate lanes are 12 feet wide.
“We have made great strides in recognizing that urban conditions require more flexibility in design guidance, and the ITE/CNU manual as well as the NACTO guides have certainly given engineers the ability to design for context and walkability,” says Wade Walker, an engineer with Alta Planning + Design. “This proposal by FHWA can make the process much simpler by eliminating the need for design exceptions on many design proposals for these type streets.”
New urbanist engineers have long argued for “decision-making that encourages engineered solutions rather than relying on minimum, maximum, or limiting values found in design criteria,” notes Peter Swift, an engineer in Gold Hill, Colorado. “This, in itself, is a remarkable admission that competent engineers are finally taken seriously!”
But dropping these standards is no panacea. “It is also worth pointing out that they still expect design speed to be a controlling criterion for streets under 50 mph,” says Marshall. “Given that the selection of a design speed is often left to the discretion of an engineer, you could still theoretically end up with streets signed for 25 mph being designed for 45 mph design speeds.”
State DOTs, which determine design on key arterials, and local DOTs and engineers, will not be directly affected by this proposal. “Until the direction is embraced by not only the state DOT’s and local staffs we will continue to run into resistance for creating truly walkable urban streets,” Walker says. Yet state and local engineers may take their cues for the federal authorities. “I can definitely envision these benefits eventually extending to state DOT and local guidelines,” says Marshall.
This proposal is part of a culture shift that is taking place at FHWA, which long supported highway standards applied to urban places. A little over a year ago, the administration gave the seal of approval for engineers to use the National Association of City Transportation Officials’ Urban Street Design Guide, which shows dimensions and standards for tighter urban streets with bike lanes and pedestrian facilities. The proposed changes can be thought of as another domino that is falling.
As of yet, the changes are just a proposal. They must go through a comment period that ends December 7. Supporters of complete streets can read the details of the changes here and support them with a comment here.
Robert Steuteville is editor of Better Cities & Towns and senior communications advisor for the Congress for the New Urbanism.