1  INTRODUCTION

Pavement performance is a function of its relative ability to serve traffic over a period of time (Highway Research Board, 1962).  Originally, a pavement’s relative ability to serve traffic was determined quite subjectively by visual inspection and experience.  However, experience is difficult to transfer from one person to another, and individual decisions made from similar data are often inconsistent.  In the late 1950s, systems of objective measurement (such as roughness meters, deflection and skid test equipment) began to appear that could quantify a pavement’s condition and performance.  These systems, along with visual distress surveys, were used to aid in making maintenance and rehabilitation decisions, which, over the years have been refined and upgraded to provide rapid, objective means to (Hicks and Mahoney, 1981):

  • Establish maintenance priorities.  Condition data such as roughness, distress, and deflection are used to establish the projects most in need of maintenance and rehabilitation.  Once identified, the projects in the poorest condition (low rating) will be more closely evaluated to determine repair strategies.
  • Determine maintenance and rehabilitation strategies.  Data from visual distress surveys are used to develop an action plan on a year-to-year basis; i.e., which strategy (patching, surface treatments, overlays, recycling, etc.) is most appropriate for a given pavement condition.
  • Predict pavement performance.  Data, such as ride, skid resistance, distress, or a combined rating, are projected into the future to assist in preparing long-range budgets or to estimate the condition of the pavements in a network given a fixed budget.
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    Today, pavement performance is largely defined by evaluation in the following categories:

  • Roughness (often called "smoothness")
  • Surface distress
  • Skid resistance
  • Structural evaluation
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    This section does the following: