The Arizona Department of Transportation (ADOT) maintains and operates several freeway corridors in the Central District with parallel one-way frontage roads. These frontage roads offer local circulation/access as well as alternate capacity during mainline incidents. There are specific guidelines and standards regarding control of access in the area of freeway ramps and crossroads when frontage roads are present but there is little guidance on traffic control – specifically the use of yield versus stop-control versus no control on the frontage road approach to the junction point. Phoenix has several frontage roads along different various freeway segments and there are differences in traffic control due to geometry and traffic volume. A formalized study is warranted to establish some guidance for current conditions and future needs.
By establishing a set of guidelines based on traffic volume, lane configuration, sight distance, speeds, distance from the Off ramp/frontage road Junction to the cross street, crash history, and/or other factors, ADOT will have a more consistent application with which to make future decisions.
Nationwide Survey of Best Practices
Working Paper 1: Existing Conditions