scope:

Purpose and Scope of Guide

The Guide for Pavement Friction provides highway pavement and safety practitioners with guidance in designing, constructing, maintaining, and managing pavement surfaces to help transportation agencies achieve safety performance goals. This version of the Guide, while published by the AASHTO Committee on Materials and Pavements, includes review and input by members of the AASHTO Committee on Safety.

This Guide contains recommendations and tools for upper-level administrators and policymakers, as well as frontline pavement and safety designers, managers, and practitioners. These recommendations are intended to supplement, but not replace, an agency's normal pavement structural or mix design practices and safety analyses. This Guide covers the following topics:

• characteristics of pavement materials and surfaces that contribute to friction (microtexture and macrotexture);

• friction-testing methods, equipment, and indices;

• analysis methods for establishing friction demand based on investigatory friction levels for the following applications: (1) design of new pavement surfaces, (2) increased potential for skid-related crashes, and (3) the need for adequate cost-effective friction restoration;

• consideration of pavement friction and safety performance; and

• guidance for aggregates, mixtures, and surface types that result in long-lasting, high-quality friction surfaces, with proper consideration of noise, economics, and other friction-related issues (e.g., splash and spray, hydroplaning, tire wear).

This Guide addresses both asphalt (i.e., flexible and semi-rigid) and concrete (i.e., rigid) pavements associated with both original construction (i.e., new construction and reconstruction) and maintenance and rehabilitation (M&R) treatments. It does not address winter maintenance issues (i.e., snow and ice removal or treatment), unpaved surfaces, or nonroadway pavements.