Impact of Quantity on Bid Cost of Unit Price Items in Design-Bid-Build Public Road Projects

Design-bid-build (DBB) projects are procured by government agencies typically through the competitive bidding process. The decision of the contracting authorities regarding which projects proceed to the bidding stage depends, in part, upon the early estimates of probable cost. Efforts are made to make this estimate as realistic as possible. Irrespective of the estimate of probable cost, the actual project cost is established by the amount of the winning bid and the cost of change orders during construction phase. The change order costs generally are known during the construction phase of the projects. However, the bid cost of projects can be estimated by analyzing the bid data of historical projects. This study will develop a method to predict the future projects’ bid cost of unit price items based on quantities of items. The regression models for various unit price items will be developed by analyzing historical bid data of 151 DBB road projects undertaken by the Clark County Department of Public Works in southern Nevada from 1991 through 2008. The total value of construction was equivalent to $841 million when converted into a June, 2011 base cost. Statistical models were developed to improve the methodologies for estimating bid-item unit pricing and to reduce variances that result in large discrepancies between engineers’ estimates and actual bid-award amounts. These regression models can be used to predict the actual bid cost of the unit price items based on quantity of the unit items.


  • English

Media Info

  • Media Type: Digital/other
  • Features: Figures; References; Tables;
  • Pagination: 13p
  • Monograph Title: TRB 91st Annual Meeting Compendium of Papers DVD

Subject/Index Terms

Filing Info

  • Accession Number: 01372564
  • Record Type: Publication
  • Report/Paper Numbers: 12-0618
  • Files: TRIS, TRB
  • Created Date: Feb 8 2012 4:56PM