At-grade intersection design covers channelization, turn lanes, corner radii, and sight triangles. Left-turn lanes are warranted per AASHTO guidelines when the design hourly volume exceeds 100 left-turning vehicles or the through volume exceeds 300 vph. Right-turn deceleration lanes are warranted when the turning volume exceeds 50 vph on roads with design speed ≥50 mph. Corner radii: minimum 25 ft for residential, 30-40 ft for collectors, 50 ft for arterials serving trucks/buses.
All work under this section shall comply with FDOT current standards and applicable AASHTO, ASTM, and federal requirements. The Engineer has authority to accept or reject materials and workmanship that do not conform to the specifications.
Source: FDOT Highway Design Manual, 2024 Edition. Pages 15–16 of 37.