Exploring the impact of project size on design-bid-build and design-build project delivery performance in highways

Abstract

The highway construction industry has been increasingly using design-build (D-B) project delivery because of its documented benefits. Only limited studies, if any, have compared D-B and traditional design-bid-build (D-B-B) project performance based on the size of projects. The existing gap was addressed by investigating the cost growth, schedule growth, and construction intensity of highway projects delivered under D-B-B and D-B with the project sizes ranging from $2 million to greater than $100 million. These projects were collected from six state departments of transportations in the U.S. with mature D-B programs. Several statistics tests including t-test, Welch’s test, and Mann–Whitney U-test were used to analyze 3888 completed highway construction projects. The results show that D-B produced a lower cost growth than D-B-B in the project size of over $10 million while D-B-B projects had lower cost growth than D-B projects in the project size from $2 million to $10 million. D-B projects also produced less schedule growth than D-B-B projects across all groups of project size. D-B-B projects had a faster work pace than D-B projects in the project size from $2 million to $10 million. The findings contribute to the project delivery body of knowledge by reporting statistically empirical comparisons between D-B-B and D-B project performance controlled by the project size. The findings may help highway agencies better understand how D-B performs under the different sizes of projects in terms of cost growth, schedule growth, and construction intensity.

Keywords:

• Highway project delivery methods
• cost performance
• schedule performance
• construction intensity
• project size

Acknowledgements

The authors would like to sincerely thank the members of the Florida DOT, Indiana DOT, North Carolina DOT, Ohio DOT, Oregon DOT, and Utah DOT for their participation in garnering all project data used for the study. Without their willingness to participate, the current study would not have been possible.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Data generated or analyzed during the study are available from the corresponding author by request.