Impact of Utilizing Construction Engineering and Inspection Consultants on Highway Construction Project Cost and Schedule Performance

State transportation agencies (STAs) are tasked with constructing and maintaining complex transportation networks while facing changes in agency construction staff with respect to age, experience level, turnover, retirement, and increasing levels of consulting services that are used to manage STA construction operations. To keep up with the increasing demands of projects, STAs are utilizing Construction and Engineering Inspection (CEI) consultants to fill the demand for construction-related human resources. However, the impact of using CEIs on project cost and schedule performance has not been quantified. The current work addresses this knowledge gap by analyzing a database of 305 completed highway construction projects across 16 STAs. The analysis found that projects that utilized CEI consultants had higher levels of full-time equivalent construction staffing than projects that utilized only agency staff. The use of CEI consultants had no impact on project cost compared with projects that relied solely on agency staff. Projects that used CEI consultants had an average cost overrun of 20.2% compared with agency-staffed projects, which experienced average schedule overruns of −7.7% (i.e., the project, on average, finished early). The schedule difference was statistically significant.