Traditional Neighbourhood Development Street Design Guidelines

This report is an ITE Proposed Recommended Practice. It includes discussion of the concepts of Traditional Neighbourhood Development (TND) (also referred to as The New Urbanism) as they relate to the role of streets in TND communities, a discussion of the community design parameters under which the Guidelines would apply, presentation of the design principles underlying the Guidelines, specific guidance on geometric street design, and an appendix that summarizes some recent findings on the relationship between urban design and travel demand.

Objectives and Background

The neighbourhood street standards embodied in the development codes of many communities (based, in large measure, on work by ITE, ASCE and other professional organizations) are intended to provide the transportation facilities appropriate for conventional suburban development patterns common over the past 40 years. Those development patterns featured separation of land uses (e.g. residential, retail, office), assumed that each household would have one or more autos available for use and that all travel, other than visits to nearby neighbours, would use a motorized vehicle. The street layouts and streets deemed appropriate under these conditions featured minimization of connectivity, in order to channel traffic to major streets and geometric designs that permitted rapid auto movement.

Architects, urban planners and developers are now proposing and building communities designed in accord with the principles of The New Urbanism. These communities feature integration rather than separation of uses with the intent that a significant proportion of trips will be retained within the community and that walking or biking rather than a car will be used for many of these trips. Even where a car is used, the shorter trips make lower speeds acceptable.

The street layouts and geometric features appropriate under these conditions are different than those appropriate for conventional development. These Guidelines are intended both to educate traffic and transportation engineers and public works professionals about design of streets for The New Urbanism and to provide an accepted professional document that can be used by engineers to support their designs and by public officials to support design approvals.

Concepts

Streets are the most visible and most important public spaces in neighbourhoods. Streets in New Urbanism communities are designed to encourage and support use of non-motorized modes for travel to local destinations. The street network and individual streets are considered to be shared spaces in which the needs of pedestrians and bicyclists are given equal or greater priority than those of auto drivers. The street layout is intended to provide many alternative paths from origin to destination. The street design is intended to require slow auto speeds and to give clear notice to drivers that these are places where slower speeds are required. The street plan features connectivity and small-blocks, but not necessarily an orthogonal grid. Streets are designed to serve the most frequent users pedestrians, bikes and local traffic. Necessary, but infrequent users (e.g. moving vans, emergency vehicles), are accommodated but their requirements do not control the street design. The use of alleys for access to parking and as utility corridors is permitted and encouraged. On-street parking as a buffer between pedestrians on adequate sidewalks, and moving traffic is encouraged.