Revision of Thirteen Controlling Criteria for Design and Documentation of Design Exceptions
The geometric design standards for projects on the National Highway System (NHS) are incorporated by reference in FHWA regulations in 23 CFR 625 and apply regardless of funding source. These design standards are comprehensive in nature, covering a multitude of design characteristics, while allowing flexibility in application. Exceptions may be approved on a project basis for designs that do not conform to the minimum or limiting criteria set forth in the standards, policies, and standard specifications. The FHWA is updating its 1985 policy regarding controlling criteria for design, applicable to projects on the NHS, to reduce the number of controlling criteria from 13 to 10, and to apply only 2 of those criteria to low speed roadways. The FHWA is also issuing guidance to clarify when design exceptions are needed and the documentation that is expected to support such requests. The FHWA's guidance memorandum, which is available in the docket (FHWA-2015-0020), transmits this policy to FHWA field offices.