Impact of Alternative Project Delivery Systems on the International Roughness Index: Case Studies of Transportation Projects in the Western United States

Abstract

The impact of alternative project delivery methods (APDM) was compared with that of the traditional method of design–bid–build (DBB) on the long-term performance of transportation projects. The metric used to quantify long-term performance differences between projects is the international roughness index (IRI), which is an indicator of ride quality. Data were collected on four alternative delivery projects on the National Highway System in Arizona and Colorado, along with data on their comparable DBB projects. Two of the projects provided northbound and southbound data and their respective comparisons, so six pairs of projects were investigated. In the study of the IRI time series, five of the six APDM projects were found to perform better than their traditional counterparts. This exploratory study contributes to the body of knowledge by starting to quantify the impact of APDM on the actual long-term performance of transportation projects.