Percent Base Design and Initial Award Performance in Design-Build Highway Projects

The project influence curve postulates that planning efforts conducted early in a project can influence project success more than later efforts. Although front-end planning has been shown to influence project performance, the impact of involving the contractor in design-build (DB) of highway projects starting at different points of percent base design has not been tested empirically. This paper reports on a study of 31 DB highway projects with base design ranging from 10% to 95%. This research is significant because it empirically tests whether initial award performance is enhanced at lower percent base design as implied by the project influence curve. The F-statistic indicates that, for this set of DB highway projects, years of agency DB experience is significantly related to initial award performance, while percent base design is not. This research addresses the misconception held by many transportation agencies that procuring a DB entity with lower percent base design will result in more innovation, leading to more agency cost savings. Additionally, an analysis of alternative technical concepts (ATCs), the primary tool for innovation in DB, indicates that project savings are attributed to multiple ATCs rather than one ATC - and the innovations adopted tend to be incremental rather than systemic, disruptive, or radical.