Urban thoroughfares project moves into high gear

Supporters of traditional neighborhood design have long wished for an industry-approved manual that gives transportation engineers the tools – and the permission – to design major context-sensitive streets for urban settings. Now hope is on the way. In August, the steering committee for Context-Sensitive Design for Major Urban Thoroughfares, a joint project of CNU and the Institute of Transportation Engineers (ITE), met in Orlando. The meeting drew prominently from the different worlds of New Urbanism and transportation engineering. New urbanist designers such as Andres Duany and Marcy McInelly sat down to work next to people such as Kenneth Kobetsky of the American Association of State Highway and Transportation Officials (AASHTO). Joined by those who bridge both worlds — engineers friendly to New Urbanism such as Rick Chellman and Norman Garrick — the group reviewed and advanced a framework for the design of major urban thoroughfares. Now project consultants are at work creating detailed guidelines for the design of several urban thoroughfare types. After further review, these guidelines will take the form of a “proposed recommended practice” issued by ITE, perhaps as early as fall 2005. At that time, it will be hard for anyone to make the case that only wide arterials meet industry standards for major roads, even in traditional city and small town neighborhoods. “A proposed recommended practice has some real industry strength behind it,” says Jim Daisa, a senior project manager at Kimley-Horn & Associates and leader of the consulting team. interest growing fast The new urbanists and transportation engineers quickly found common ground at the meeting. Interest in context-sensitive design is growing fast among mainstream transportation specialists, in part because the public has become more forceful in rejecting road designs that are viewed as context insensitive. “There are lots of pressures moving the engineering community toward broadening how they look at design,” says Garrick, associate professor of transportation engineering at the University of Connecticut and the initiative leader for CNU’s Transportation Task Force. “Currently they waste money since opposition makes project development take much longer. Or the projects just don’t get done. That’s another frustration.” Despite these common interests, creating road design standards that are acceptable to both the new urbanist and engineering communities is no small feat. The AASHTO “green book” has driven road design for decades and it is primarily concerned with the “efficient, safe, and fast movement of cars and trucks,” says Daisa. Traditional urban design assigns a more complex role to roads, insisting that they serve pedestrians, bicyclists, and transit riders as well as drivers, and that they help create an urban sense of place. So where AASHTO recognizes two contexts – urban and rural – and uses the distinction primarily to set speed limits, the new framework for urban thoroughfares recognizes seven contexts ranging from natural areas to urban cores and districts. By recognizing the correct context, engineers can determine the appropriate thoroughfare options. The AASHTO manual is also based on a system in which traffic follows one expected route – from cul-de-sacs and collectors to the major arterials serving them. Therefore, arterials need to be big enough to handle sizable peak loads. The new guidelines recognize that urban thoroughfares function as part of grid systems that send traffic filtering in many directions and provide lots of travel options. “One of the things we’ll be making clear to the practitioners is that if the network can accommodate the traffic demands, you don’t need to worry about the individual street so much,” says Daisa. To promote greater acceptance of the new guidelines, members of the project steering committee agreed on a key compromise: They agreed to use standard AASHTO terminology in naming the urban street types. As a result, types such as boulevards and avenues will be treated as sub-categories of arterials. “To maintain credibility with the people who design roads, we determined that we had to be consistent with AASHTO,” says Daisa. “Otherwise, the guidelines would probably be pushed aside and ignored.” The resulting manual won’t replace the AASHTO manual, just “fill in its gaps,” says Garrick. “We want this document to drop into state DOT design manuals,” adds Daisa. When that happens, new urbanists will certainly be cheering. “It’ll give us another tool in our tool box,” says Garrick. “And cities and towns need the support. They get beaten up by the states that say there is no national imprint that says urban streets are OK.” u