The stated objectives of this project are as follows: a) determine the specific design configurations when a median barrier is justified b) determine what slope and width combinations should be considered for conditions where a median barrier is not justified, and c) develop improved guidelines for the use of median barriers and for the selection of median widths and slopes on new and existing high-speed, divided highways. As a fundamental condition, these guidelines should be suitable for inclusion in the next editions of Americal Association of State Highway and Transportation Officials AASHTO's Roadside Design Guide and/or AASHTO's Policy on the Geometric Design of Highways and Streets. This project involves the determination of median slope and width based on safety investigations and considerations. In final roadway design, however, slope and width must be considered along with other factors, particularly drainage, which is outside of the scope of this research effort. The focus of this investigation is limited to roadway segments and excludes intersections. Median intersection design was the subject of a recently completed NCHRP study, which was published as NCHRP Report 375. Therefore, efforts will be made to eliminate intersections during data collection and analysis. (A)
Abstract