Abstract
The results of a study of noise barrier costs in the United States are presented. A survey was made of each state highway agency and the FHWA to codify all barriers constructed through 1987. Costs associated with the construction of the barriers were then made current through the fourth quarter of 1988 using FHWA quarterly price trends for federal-aid highway construction. New curves correlating cost per linear foot were then developed using standard statistical techniques. The new curves have been incorporated into the OPTIMA code. In addition, other changes to OPTIMA have been made and are described.