West Mesquite Interchange Design-Build Project
Project Information
The Nevada Department of Transportation and the City of Mesquite, in cooperation with the Federal Highway Administration and the Regional Transportation Commission of Southern Nevada, is improving the I-15 interchange 120 in west Mesquite.
The West Mesquite Interchange Design-Build Project will improve travel, safety and access by reconstructing the existing I-15 west Mesquite exit to include improved interstate exit and on ramps, modern traffic roundabout intersections and reconstructed bridges. Falcon Ridge Parkway underneath I-15 will also be realigned and widened, as well as extended to the southwest to connect with Leavitt Lane. In addition, the project will enhance drainage, lighting and landscape and aesthetics.
Project Schedule/Cost
The West Mesquite Interchange Design-Build Project has received all necessary approvals and has been awarded to W.W. Clyde & Co. Construction. W.W. Clyde’s contract is for $14,350,513.00 and has a total duration from notice to proceed to substantial completion of 365 calendar days. This project cost and schedule represent a significant savings from what was estimated and are indicative of the innovation and value that the design-build process and this contractor have brought to the project.
Official notice To proceed was given to W.W. Clyde on May 6, 2011. Final design began shortly thereafter with major construction elements of the project to begin in August and peak during the winter of 2011-2012. The project is scheduled to be substantially complete in May 2012 with all roads fully functioning and only minor items of work to remain.
Modern Traffic Roundabouts
Additional Roundabout Information
Roundabouts are one-way circular intersections in which traffic flows around a center island without stop signs or signals.
Vehicles entering the roundabout yield the right-of-way to traffic already in the roundabout. Because roundabout traffic enters and exits through right turns only and speeds are reduced, the occurrence of severe crashes is substantially less than in many traditional four-way intersections. In fact, the Insurance Institute for Highway Safety reports that motor vehicle crashes involving injuries have declined by up to approximately 80% in intersections where roundabouts have been installed.
The lower speeds within roundabouts also allow entering traffic to access smaller gaps between circulating vehicles, increasing traffic volume and decreasing delays, congestion, fuel consumption and air pollution.
Benefits of Roundabouts
- Safer than signalized intersections
- Reduces frequency and severity of crashes
- Reduces traffic delays / increases traffic capacity
- Can slow excessive traffic speeds while still improving traffic flow
- Reduced long-term operational costs
- More environmentally-friendly than traditional intersections due to less vehicle emissions, fuel use and noise
- More aesthetically-pleasing
Design-Build Projects
The West Mesquite Interchange improvements are planned to be built as a design-build project. In design-build projects, design and construction often progress at the same time; reducing project costs and the time it takes to complete the project. In addition, both design and construction are contracted with a single contractor. This system is used to minimize project risk. The design-build process also offers greater project innovation and collaboration between the Nevada Department of Transportation, affected local agencies, project stakeholders and the construction partner contracted to build the project. NDOT has used the design-build method in the past to great success. The Department’s first design-build project, the I-15 North Design-Build in Las Vegas, completed eight months ahead of schedule in late 2009.