Author Description

TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 227: Design of Interchange Loop Ramps and Pavement/Shoulder Cross-Slope Breaks is presented in two parts. Part 1 presents design guidance for interchange loop ramps based on observational field studies and safety analyses and includes suggestions for the next edition of A Policy on Geometric Design of Highways and Streets published by the American Association of State Highway and Transportation Officials (AASHTO). Part 2 assesses AASHTO's current design policy for pavement/shoulder cross-slope breaks on superelevated horizontal curves.