•  2003 Project Highlights
•  Evaluation Criteria

I-405 - Coal Creek Parkway to SR 522

King County

Design: Construction Management: Schedule: Cost: Engineers Estimate: $2,900,073 Contract Award Amount: $2,545,684 Final contract cost:  $2,877,260 The final cost of the project is approximately 13% higher than the bid amount. A good portion of the cost overrun is associated with reconstructing the shoulders and underestimated traffic control costs. Although the cost growth is less than 15%, the main issues that caused the growth, as stated above, should have been anticipated during project design.

This Interstate 405 project extends from south Bellevue near Factoria to the SR 522 Woodinville interchange. Crews installed permanent high occupancy vehicle (HOV) lane stripes, safer law enforcement pullout areas, and improved drainage and signing. The plastic HOV lane striping enhances safety as it is more readily visible than paint stripes. It's also more durable, which reduces maintenance costs and minimizes costly lane closures and related traffic delays. Law enforcement pullouts were removed and new pullouts that meet Federal safety guidelines were constructed. Drainage improvements help reduce the risk of accidents and keep traffic moving by keeping water off of the freeway when it rains. Variable message signs were also installed to help provide drivers real-time traffic information.

Construction Summary

This project was completed on time, but 13 percent over the contractor's bid amount. This cost overrun was largely due to underestimated traffic control and an unanticipated need to reconstruct the highway shoulders. These could have been addressed during project design.

There was very good teamwork and communication between WSDOT and its contractor, Tri-State Construction. This helped keep this project on-schedule and near budget despite the problems that arose. To complete the work, traffic was directed away from the median at three locations on heavily traveled I-405. As a result, traffic on the outside lanes drove on highway shoulders. These shoulders deteriorated rapidly as they were not originally built to handle constant traffic. The shoulders were rebuilt at considerable cost.

Traffic impacts were severe given the significant amount of vehicles using I-405. Tri-State Construction proposed weekend HOV lane closures to complete the work. This aggressive approach reduced traffic congestion significantly and saved the state more than $100,000 in traffic control costs. Press releases and variable message signs were used to keep drivers apprised of construction activities and schedules.

Contractor:
Tri-State Construction, Bellevue, WA.

WSDOT Contact:
David Lindberg, Project Engineer
Phone: 425-739-1750
E-mail: lindbed@wsdot.wa.gov

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