Phase 2, NDOT EA 73320, will be the portion of the project that extends from Silverline Road to the western limits of the overall project. The west end of Phase 2 will tie into the Nevada interchange which was completed in October of 2010 as part of the FHWA Hoover Dam Bypass Project. Phase 2 will run around the south and east sides of Boulder City. As the alignment moves northeast towards Lake Mead, it will crest the Eldorado Mountains and then descend down through the Lake Mead National Recreation Area to the Nevada interchange. The overall Phase 2 project length is approximately 12.5 miles.
Due to the mountainous terrain and environmental constraints associated with the Eldorado Mountains and Lake Mead National Recreation Area, the design criterion for the project has been split into two sections. The eastern section from the US 95 interchange to the Intertie Access Road overpass utilizes a design speed of 70 mph and a 42 foot median between northbound and southbound travel lanes. The remaining portion of the project from the Intertie Access Road to the Nevada interchange has a 55 mph design speed and utilizes a concrete barrier divided section. Phase 2 is anticipated to have an average Year 2031 daily traffic volume of 11,200 vehicles per day.
Phase 2 is being administered by the RTC as a single Design-Build contract. The RTC and NDOT have been working together since the passage of AB413 to procure a design-builder to bring the design to a 100% level as well as constructing the entire Phase 2. Upon project completion, the entire Boulder City Bypass Phase 2 will be relinquished to NDOT in perpetuity for ownership and maintenance responsibilities. Phase 2 right-of-way requirements have been established and will require property to be acquired from the city of Boulder City, the Western Area Power Administration (WAPA) and the National Park Service for right-of-way within the Lake Mead National Recreation Area.
Phase 2 consists of numerous environmental mitigations that were listed as part of the Record of Decision. Several key mitigations exist that need to be addressed in more detail as the project progresses.
A final biological assessment, consultation and clearance with the Nevada Division of Wildlife and US Fish and Wildlife Service is currently under way. This consultation will include discussion on the treatment of the proposed wildlife crossings for both large bridge structures and smaller culvert/RCB crossings.
As part of the Environmental Impact Statement, an overlook vista was identified as part of the Record of Decision. The preliminary location identified the vista be located at the summit of the Eldorado Ridge. Several concerns with this location include vehicles exiting and entering from the vista into mainline traffic, pedestrian conflicts and additional excavation required. One alternative location recommended for further investigation is a vista overlook on the Eldorado Ridge within Boulder City boundaries, near mainline station 745+00.This would allow for the vista to be located on shallower grades, require less excavation and provide additional funding resources such the Southern Nevada Public Land Management Act funds.
Additional construction and design mitigations are listed in the Record of Decision for the project.