2009 - USA - Estimating Unit Costs for Construction

Availability of historical unit cost data is an important factor in developing accurate project cost estimates. State highway agencies (SHAs) collect data on historical bids and/or production rates, crew sizes and mixes, material costs, and equipment costs, including contractor overhead and profit. The goal of this synthesis is to identify how state highway agencies develop unit prices for construction and maintenance projects. The synthesis approach consists of a comprehensive online survey, covering every aspect of unit cost development, to identify the state of practice in state highway agencies and interviews with several representative SHAs to gain a better understanding of the practices followed for unit cost development. This study finds that even though SHAs collect and store historical cost data, they do not have a formal and documented process for adjusting unit costs for project characteristics and market conditions.