Measurements of pavement condition and performance for Texas highways using sampling techniques

Abstract

Cost-effective, objective performance information obtained on a highway network better enables highway maintenance managers to make informed decisions. Three methods which can be used to obtain such objective information are: mass inventory, partial, and sampling surveys. Of the three, sampling surveys and a mass inventory of data available from District 21 are examined in depth. Five types of sampling surveys are described including examples for each. Of the five, a stratified two-stage sample survey was elected for use in Texas. The sample was obtained by first randomly selecting counties within each highway district, then randomly selecting two-mile highway segments within each county. Approximately one percent of the total statewide centerline mileage was sampled using this technique. Various kinds of data were obtained for each of the sampled highway segments with Serviceability Index, Pavement Rating Score, and Surface Curvature Index examples used to demonstrate the kinds of inferences which can be made. Sampling and year-to-year variations of these data types are discussed and recommendations are made which will improve the consistency of the data obtained with the visual condition evaluation procedure. The questions of what kind and how large of a sampling survey which should be used are examined. ...