Accuracy Analysis of Selected Tools for Estimating Contract Time on Highway Construction Projects

In many highway construction projects, the time available to complete construction is set by the contract documents. Most transportation agencies have developed tools to assist project planners in estimating the amount of time required to complete the project but how accurate are these systems in estimating project duration? The current work examines the accuracy of integrated scheduling systems from two state transportation agencies in estimating contract time for previously completed Kentucky highway construction projects. The accuracy of the systems where tested against project data from 66 completed Kentucky Transportation Cabinet Projects. The analysis revealed that the average accuracy of both systems in predicting project duration was greater than ±200% across a variety of projects. A pilot study of the use of multivariate regression analysis of the data from 66 completed Kentucky Transportation Cabinet projects was performed to identify specific combinations of work item quantities with the engineer's cost estimate that produce the most accurate estimate of project duration. The accuracy of the developed regression equation in predicting highway construction project duration was ±25%. The current work contributes improved understanding of the accuracy of integrate scheduling systems in predicting highway construction duration.