NACTO’s design guide family — the Urban Street Design Guide (street and intersection design elements, lane widths, curb extensions, signal strategy for urban contexts) is readable free in full on nacto.org; Transit Street Design Guide content is on the site too. The Urban Bikeway Design Guide 3rd ed. (2025) is not yet free online — NACTO has announced free posting, so check back.
Why: AASHTO/FDOT cover the state system; NACTO is the urban/complete-streets design language City of Tampa and St. Petersburg increasingly reference in scopes, Vision Zero work, and plan comments — you need the vocabulary even when FDM controls.
When: local-street and downtown projects, curb extension/crossing/transit-stop concepts, writing justification language an urban agency will recognize.
NACTO is guidance, not an adopted standard — on the SHS, FDOT Design Manual (FDM) criteria and MUTCD compliance control. Use NACTO for context framing and treatment vocabulary, never as a criteria override.
See also: FDOT Context Classification · FDOT Design Manual (FDM) · MUTCD