New Approach for Developing an Asphalt Concrete Overlay Transition Standard

Abstract

Smooth transitions are necessary to ensure the desired ride for the traveling public. Transitions are used within projects as new pavement approaches a bridge to avoid adding unnecessary dead load on the bridge. As roadways pass beneath bridges, transitions are used to avoid encroaching on the existing vertical clearance. This paper describes Virginia Department of Transportation (VDOT) efforts to develop an effective standard for transition details. An in-depth analytical model considering the vehicle dynamics was developed to establish the transition lengths for various overlay thicknesses and speed limits. Virtual profiles using these lengths and overlay thicknesses were generated to assess the ride over the transition. Simplified methods to calculate transition lengths were introduced.