New urbanists hold summit on streets

Experts debate alternatives to conventional thoroughfare design and street networks. December 10 and 11, 50 CNU members met in Oakland, California for a groundbreaking meeting about planning and designing streets. The gathering included architects, planners, urban designers, landscape architects, engineers, and transit operations experts. This Transportation Summit had two main topics, the street network and street design. Participants were left with a common language, new ideas, and a raft of new questions to answer. The most productive part of the meeting was the discussion of reforming the street classification system. For years, new urbanists have dismissed the conventional classification of “local, collector, or arterial” as the enemy of walkable streets. Meeting participants suggested new terms that more accurately describe the size, function, and design of streets. Their terms were intentionally linked to the types of place in which different street types function best. The goal was to outline design guidelines for regional streets — what topics would be included, and how to present the information. Early in the meeting, Peter Calthorpe urged attendees to focus on issues beyond the neighborhood. “We’ve done well at the neighborhood scale,” he said, but regionally urbanists have not had a clear message. “We treat existing arterials as unchangeable elements of the landscape.” Participants agreed, and did not spend much time discussing local streets or interurban roads. For regional roads, Calthorpe suggested eliminating the term “collector” and replacing it with “connector.” Participants suggested that other types of streets CNU needs to address were avenues and boulevards. There was interest in guidance for rural or suburban areas, and for districts like industrial zones. However, participants agreed to leave those items out of the scope of this initiative, focusing on the kinds of arterials that exist in the centers of villages, towns, and cities, and in walkable neighborhoods. agreement on design There was broad agreement on several topics related to design. Starting with three matrices, participants developed a matrix with street types on one axis and urban context on the other. Street types are defined by maximum size and maximum speed. The definition of urban context is still vague, but there is some agreement that an adapted Urban Index could incorporate Transect zones as well as more site specific land-use criteria. For each matrix cell, participants decided on a set of criteria to be defined. Participants spent hours determining how to describe urban context. At the previous day’s meeting with the Institute of Transportation Engineers (ITE) (see sidebar), CNU initiative leader Fred Dock and ITE’s Brian Bochner presented a three-dimensional matrix. It combined the street type (regional, community, or local) and adjoining land uses. They refined this proposal after meeting attendees criticized it as too complex. Rick Hall, Peter Swift, and Rick Chellman introduced another matrix, theirs relying explicitly on the Transect to describe both regional context and surrounding land use. Calthorpe created a matrix that used the Urban Land Institute’s categories for job and commercial centers — neighborhood center, town center, and city center. Late in the meeting, participants seemed attracted to using a modified Urban Index, a rating that measures how likely an urban design is to attract pedestrians. Some characteristics that could be included are anticipated employment density and intersection frequency. The precise description of context is still up for discussion. Participants came up with 19 design specifications that will vary depending on street type and context. These include bicycle facilities, intersection treatments, and lighting. With limited time, participants did not discuss actual specifications for any of the street types in their matrix. Network design Street networks, a topic introduced by Milwaukee Mayor John Norquist, produced more questions and fewer conclusions than street design. Norquist kicked off the discussion by highlighting an opportunity for replacing expressways with more human-scale surface streets in cities. Freeway structures are reaching the end of their design life, making removal or reduction a real option. Transportation system modeler Jerry Walters demonstrated that there are methods for making regional arterials more bearable where they pass through downtowns. Multi-way boulevards were popular among participants, though people recognized that they are expensive to build and maintain, and that they call for relatively intense urbanism. Thus, they will not replace very many miles of arterial. Walters showed how two-lane, one-way couplets can provide narrower streets through a town while maintaining regional traffic capacity, but participants were skeptical of whether such streets could be kept to safe speeds. Several issues still need to be better understood before new urbanists can even describe their goals for the regional scale, much less develop strategies for implementation. First, we need to define what a new urbanist network is. Examples of good regional networks are also needed. We need standard names for different types of places. While CNU members have followed Andres Duany’s lead in developing the Transect of regional contexts, the Urban Land Institute has a taxonomy of retail and job centers, and Hall, Swift, and Chellman have developed a set of “context zones,” Summit attendees were unwilling to create new jargon, hoping to be able to describe places without new terms. An item that is very much up for debate is the best frequency of through-streets. Planner Kevin Klin-kenberg has called for through streets at least every half-mile. Calthorpe recommends larger arterials every mile, with more frequent small connector streets. The state of Oregon now allows municipalities to set maximum spacing of connector streets, and Calthorpe said he had heard of the rule being used to create streets every 800 feet. The retrofit of existing networks is a tremendous challenge, in both suburban and rural situations. Fred Dock, Carol Swensen, Phil Erickson, and Kevin Klinkenberg brought to the summit real-world problems that they are working on in their practices. The problems, from Minneapolis, Kansas City, and Boise, demonstrated to participants that adding connectors to meet regional needs, support walkable neighborhoods and centers, and make mass transit viable was difficult at best.