Approach for Estimating Inspection Staffing Needs for Highway Construction Projects

Construction inspectors are the primary workforce in the highway construction industry who ensure that the work on infrastructure projects meets or exceeds the quality standards set. However, there is a growing concern in state departments of transportation (DOTs) about the inspection process because of the declining availability of experienced inspectors. This study proposes an approach for estimating inspection staffing needs for highway construction projects. Data from 157 construction projects completed between 2017 and 2021 were used to evaluate project inspection staff size based on the project type, cost, and duration. A total of 35 core inspection items were identified by carrying out a content analysis of construction inspection documents. Then, a focus group of 18 experts from the Kansas DOT was conducted to verify the list of 35 cost inspection items and evaluate the number and experience of inspectors required for each item. The four project types included in the analysis are as follows: grading/surfacing; sealing; surface recycling and overlay; and bridge repair. The analysis showed that the inspection staffing needs depend on project type, duration, and size. The grading/surfacing and bridge repair projects require more inspection staff than the sealing, and surface recycling and overlay projects. The result of a Spearman's correlation analysis indicated that there is a significant association between the risk level of an inspection item and the number and experience of inspectors required for that item. The findings from this study may help state DOTs identify their needs for inspection staff and improve the quality of highway construction projects.