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1 Roadway designers strive to provide for the needs of highway users while maintain- ing the integrity of the surrounding context, community values, and environment. Unique combinations of design requirements, controls, and constraints that often conflict among different roadway users require unique design solutions. The guidance supplied by NCHRP Research Report 880: Design Guide for Low-Speed Multimodal Roadways (the Guide) is based on established best practices and is supplemented by recent research where possible. The U.S.DOT encourages public agencies, professional associations, advocacy groups, and others to commit themselves to fully integrating bicycling and walking into their trans- portation policies and programs. The U.S.DOT also recommends that the design manuals commonly used by highway designers and that cover roadway geometrics, roadside safety, and bridges should incorporate design information that integrates safe and convenient facilities for bicyclists and pedestriansâincluding people with disabilitiesâinto all new highway construction and reconstruction projects. The intent of this Guide is to provide best practice guidance to the designer by refer- encing a range of acceptable elements, criteria and values for critical dimensions in the design of low- to intermediate-speed (45 mph and lower design speed) roadways with a mix of users. Good design involves balancing safety, mobility, and preservation of scenic, aesthetic, historic, cultural, and environmental resources. The Guide provides extensive information and guidance for multimodal design, but it is not intended to be a detailed design manual that eliminates the need for the application of sound principles by a knowledgeable design professional. Sufficient flexibility exists in national design policy (such as AASHTOâs A Policy on Geo- metric Design of Highways and Streets, called the Green Book) and its use is also encouraged throughout this Guide to create independent designs tailored to particular combinations of travel demands, context and community goals and values. When ranges of dimensional values are presented, additional information is often provided to assist the designer in deciding whether the upper, lower, or intermediate values are most appropriate for a particular situa- tion. Engineering judgment is necessary in any design process to select the best combination of geometric controls, criteria and elements that best balances the safety, accessibility and mobility of all user travel modes. The Green Book emphasizes the joint use of transportation corridors by pedestrians, bicyclists, and public transit vehicles. It also recommends that designers recognize the implications of this sharing of the transportation corridors and are encouraged to consider ânot only vehicular movement, but also movement of people, distribution of goods, and provi- sion of essential services.â S U M M A R Y Design Guide for Low-Speed Multimodal Roadways
2 Design Guide for Low-Speed Multimodal Roadways This Guide is intended to assist designers in establishing a balance between the operational efficiency, comfort, safety, and convenience for modes on the low- and intermediate-speed roadways. Context sensitivity and environmental quality are also key considerations in the design process and should result in aesthetic consistency with the surrounding terrain or urban setting as appropriate to create roadways that are safe and efficient for users, acceptable to non-users, and in harmony with the environment.
