Engineering judgment must be applied when developing designs for roadway improvement projects. The American Association of State Highway and Transportation Officials’ (AASHTO’s) guidance about providing for flexibility in design encourages agencies to incorporate the objectives of CSS principles such as substantive safety performance into project development. Flexibility in design (as discussed in AASHTO’s A Guide for Achieving Flexibility in Highway Design and the Federal Highway Administration’s [FHWA’s] Flexibility in Highway Design) helps agencies deliver solutions that balance safety and mobility for all users with the preservation and enhancement of community and environmental resources. That concept of “flexibility in design” is encouraged through use of an open, collaborative, and creative thinking process by which flexibility is exercised in (a) design approach, (b) use of standards and criteria, (c) implementation of solutions, and (d) consideration of the context of the area in which the project is being implemented, such as improvements to the street side or multi-modal considerations that provide integration of land use, transportation, and infrastructure needs.
– From Integration of Safety in the Project Development Process and Beyond: A Context Sensitive Approach – ITE 2015
