Designing Walkable Urban Thoroughfares
The context sensitive solutions (CSS) approach keys thoroughfare types with place types that reference aspects of the roadside context. An implicit goal of CSS is to reduce the dominance of roadway capacity in roadway design decisions by more directly integrating other modal and community design considerations particularly those design details critical to supporting non-auto modes in the urban context. The approach also strives to maintain an optimal balance between desired roadway operations and the roadside context.
Basic elements of the approach are as follows:
Seven context zones are defined in a transect that categorizes land use contexts according to character, density of activities and intensity of development, ranging from natural to urban core or assigned district as shown in Figure 1.
Thoroughfares are categorized into types using functional class to determine role, and using design characteristics tailored to each roadside context that they pass through. The thoroughfare type is governed by design elements and features that fit within a particular context, such as sidewalks, planting strips, medians, bike lanes, on-street parking, and access location.
The context zone and community vision are matched to desired characteristics for a thoroughfare. This may result in tradeoffs between automobile capacity and multimodal design elements.
The report emphasizes the importance of network planning for access management as follows:
The need for rigorous access management in compact urban areas can be lessened by proper network planning, because traffic distributed to a grid of streets reduces the concentration on any one thoroughfare.
The following principles define access management techniques:
Classify the street system by function, context and thoroughfare type;
Establish standards or regulations for intersection spacing (see Chapter 3 for guidance);
On streets that serve an access function (the focus of this report), minimize curb cuts in urban areas to reduce conflicts between vehicles, pedestrians and bicyclists, locate driveways and major entrances away from intersections and away from each other to minimize effects on traffic operations, minimize potential for crashes, provide for adequate storage lengths for turning vehicles and reduce conflicts with pedestrians using the streetside;
Use curbed medians and locate median openings to manage access and minimize conflicts; and
Use cross streets and alleys to provide access to parking and loading areas behind buildings.
Chapter 3 of the report addresses network planning and Chapter 8 addresses streetside design.
The CSS transect approach provides one framework for organizing access management techniques according to context. It is especially applicable in the context of corridor management planning, but could potentially be adaptable for use in statewide access classification systems. One impediment to accomplishing the CSS approach for access management is its dependence on effective network planning, which is often absent at the local government level. Most communities in the US continue to achieve network primarily through the development process, with ad hoc and inefficient results. Nonetheless, more effective network planning is essential to access management and should be actively promoted in the AMM2.
Design parameters for a thoroughfare are provided for each context zone with a row dedicated to access management. Virtually all of the items listed under the Traveled Way heading are pertinent to access management and several could be expanded to cover other access management parameters, such as, signalized and unsignalized access spacing, spacing of median openings, and auxiliary turn lane use.
Institute of Transportation Engineers. Designing Walkable Urban Thoroughfares: A Context Sensitive Approach, ITE Recommended Practice, (2010)