Which publication provides geometric design standards for roadways?

Which publication provides geometric design standards for roadways?

• A. HCM
• B. MUTCD
• C. NCHRP
• D. AASHTO Green Book

Answer: (D)

Geometric design standards for roadways come from the AASHTO Green Book. This publication, Geometric Design of Highways and Streets, provides the official criteria engineers use for roadway geometry—horizontal and vertical alignments, sight distance, stopping distances, lane and shoulder widths, cross-section elements, grades, and superelevation. It serves as the authoritative reference for setting design speeds, curve radii, sight lines, and overall roadway layout to balance safety and efficiency. The other items have different purposes: the Highway Capacity Manual focuses on capacity and operations; the MUTCD covers traffic control devices and signaling guidance; NCHRP publishes research studies, not the standard geometric design criteria.

Geometric design standards for roadways come from the AASHTO Green Book. This publication, Geometric Design of Highways and Streets, provides the official criteria engineers use for roadway geometry—horizontal and vertical alignments, sight distance, stopping distances, lane and shoulder widths, cross-section elements, grades, and superelevation. It serves as the authoritative reference for setting design speeds, curve radii, sight lines, and overall roadway layout to balance safety and efficiency. The other items have different purposes: the Highway Capacity Manual focuses on capacity and operations; the MUTCD covers traffic control devices and signaling guidance; NCHRP publishes research studies, not the standard geometric design criteria.