23 U.S.C. § 217 — Bicycle transportation and pedestrian walkways

(a) STP and Congestion Mitigation Program funds: With the Secretary's approval, a state can use funds it receives under sections 104(b)(2) and 104(b)(4) to build sidewalks, bike lanes, and shared micromobility facilities, and to carry out projects that improve safety for bicyclists and pedestrians. (b) National Highway Performance Program funds: With the Secretary's approval, a state can also use funds under section 104(b)(1) to build sidewalks and bike facilities on land next to a National Highway System road. (c) Federal Lands Highway funds: Money set aside for forest highways, forest roads and trails, public-lands roads and trails, park roads, parkways, Indian reservation roads, and public-lands highways can also fund sidewalk and bike-facility construction, at the discretion of whichever department administers that money. (d) State bicycle and pedestrian coordinators: Each state receiving money under sections 104(b)(2) and 104(b)(4) must use part of it to fund up to two "bicycle and pedestrian coordinator" positions in its transportation department, to promote and facilitate more walking and biking — including developing facilities and running education, promotion, and safety programs. (e) Bridges: If a federally funded bridge-deck replacement or rehabilitation is on a highway where pedestrians or bicyclists are allowed at both ends of the bridge, and the Secretary decides safe accommodation for them is affordable as part of the project, the bridge must be replaced or rehabilitated to provide that safe accommodation. (f) Federal share: Building a sidewalk or bike/micromobility facility counts as a highway project, and the federal share is figured under section 120(b). (g) Planning and design: (1) Metropolitan planning organizations and states must give bicyclists and pedestrians real consideration in their comprehensive transportation plans, and must consider bike facilities and sidewalks in new construction and reconstruction, except where biking or walking isn't permitted. (2) Transportation plans and projects must provide for the safety and connected routes of bicyclists and pedestrians, including — where appropriate — audible traffic signals and signs at street crossings. (h) Motorized vehicles: Motor vehicles generally can't be allowed on trails and walkways built under this section, except for: (1) maintenance; (2) snowmobiles, when snow conditions and state or local rules permit; (3) motorized wheelchairs; (4) electric bicycles, when state or local rules permit; and (5) other circumstances the Secretary decides are appropriate. (i) Transportation purpose: No bicycle project can be funded under this section unless the Secretary has determined it will be principally for transportation, not recreation. (j) Definitions: (1) "Bicycle transportation facility" means a new or improved lane, path, or shoulder for bicyclists, and a traffic control device, shelter, or parking facility for bikes. (2)(A) "Electric bicycle" means a bicycle with fully working pedals, a seat, and an electric motor under 750 watts, that can safely share a bike facility with other users, and that fits one of three classes. (B)(i) "Class 1" assists only while the rider pedals and stops assisting at 20 mph. (ii) "Class 2" has a motor that can propel the bike on its own, but can't assist at 20 mph or more. (iii) "Class 3" assists only while pedaling and stops assisting at 28 mph. (3) "Pedestrian" means anyone traveling by foot, and any mobility-impaired person using a wheelchair. (4) "Wheelchair" means an indoor-usable mobility aid, manual or motorized, designed for and used by people with mobility impairments.