Sampling method for cost estimation of highway noise barrier infrastructure

A methodology for system-wide estimation of environmental mitigation costs based on a stratified random sampling technique is presented, and its application is illustrated using the highway noise barrier needs of a large metropolitan area. The system-wide highway noise barrier infrastructures cost figures are usually based on rough estimates. A methodology is needed to systematically estimate the cost of the entire system using the cost data from a representative sample of sites. Random sampling and stratified random sampling were not appropriate. A balanced stratified random sampling methodology for selecting a small number of representative sites when the sample size is smaller than the number of combinations of strata was developed. A representative sample of sites was selected, and the cost data from the sites were used to estimate the construction cost for the entire noise barrier system. This paper discusses criteria for selection of the representative sites, development of a procedure for selecting the sites, and three approaches for estimating the noise barrier construction cost for the entire study area using the balanced stratified random sampling technique. The methodology is generic for system-wide estimation of environmental mitigation costs, and noise mitigation is simply used as a sample application.