36 CFR Part 1190, Proposed Accessibility Guidelines for Pedestrian Facilities in the Public Right-of-Way; Shared Use Paths: Supplemental Notice of Proposed Rulemaking (SNPRM)

R302.5.5 Regulatory Constraints. Where compliance with R302.5.1 or R302.5.2 is precluded by federal, state, or local laws the purpose of which is to preserve threatened or endangered species; the environment; or archaeological, cultural, historical, or significant natural features, compliance is required to the extent practicable.

As proposed in the NPRM, R302.5 would require the grade of pedestrian access routes contained within a street or highway right-of-way, except at pedestrian street crossings, to not exceed the general grade established for the adjacent street or highway; and the grade of pedestrian access routes not contained within a street or highway right-of-way to be 5 percent maximum. R302.5.1 would require the grade of pedestrian access routes contained within a pedestrian street crossing to be 5 percent maximum.

The SNPRM would renumber R302.5 to include a general provision in R302.5; the specific provision for the grade of pedestrian access routes contained within a street or highway right-of-way in R302.5.1; the specific provision for the grade of pedestrian access routes not contained within a street or highway right-of-way in R302.5.2; and the specific provision for the grade of pedestrian access routes contained within a pedestrian street crossing in R302.5.3.

The SNPRM would add new provisions at R302.5.4 and R302.5.5 that would require compliance with the grade provisions in R302.5.1 or R302.5.2 to the extent practicable where compliance is not practicable due to physical constraints and where compliance is precluded by regulatory constraints. We propose to add these new provisions in response to public comments on the ANPRM, which included draft technical provisions for grade similar to those proposed in the R302.5. The comments noted that physical or regulatory constraints may prevent full compliance with the grade provisions. Physical constraints would include existing terrain or infrastructure, right-of-way availability, a notable natural feature, or similar existing physical constraints. Regulatory constraints would include federal, state, or local laws the purpose of which is to preserve threatened or endangered species; the environment; or archaeological, cultural, historical, or significant natural features.

The proposed provisions are consistent with the AASHTO Guide. The AASHTO Guide recommends that the grade of a shared use path should not exceed 5 percent; but, where the path is adjacent to a roadway with a grade that exceeds 5 percent, the grade of the path should be less than or equal to the roadway grade. The AASHTO Guide notes that grades steeper than 5 percent are undesirable because ascents are difficult for many path users, and the descents can cause some path users to exceed the speeds at which they are competent or comfortable. See AASHTO Guide, 5.2.7 Grade.