Nevada State Route 439

As the plans for TRIC were realized with many large companies moving in,[7] greater plans were made for USA Parkway. As early as 2004, the road was proposed to connect with US 50 near Silver Springs, for a total distance between I-80 and US 50 of about 18 miles (29 km).[8] The connection to Silver Springs would increase regional mobility and provide air-freight shipping possibilities at nearby Silver Springs Airport.[9] Proponents of the USA Parkway southern expansion proposed the idea of having USA Parkway accepted into Nevada's state highway system as State Route 805, but NDOT did not take such action.

In 2012 and early 2013, the road network was found to fall short of TRIC's future needs. Expansion for 2017 was calculated to have a network-wide benefit–cost ratio of 9.1 (with 30-year benefits of $600 million for costs of $66 million),[10][11] and a travel reduction time of 38%,[12] as the increased traffic could use the shorter 439 for TRIC and avoid the congestion around Reno.

Tesla announced plans to locate its "Gigafactory" battery production facility at TRIC in September 2014.[13] By 2015, NDOT had officially recognized the northernmost 6.259 miles (10.073 km) of USA Parkway as State Route 439.[14] Inadequate traffic management on SR 439 sometimes caused traffic to back up out on the freeway, and the Walmart trucks struggle to operate on time.[15] At the end points of the future SR 439, the combined traffic of I-80 and US 50 was around 30,000 vehicles per day in 2015.[16] The interchange between I-80 and SR 439 had a low level of service as of 2016, causing congestion. The Regional Transportation Commission of Washoe County views the improvements as insufficient for the expected area development.[17]

To support the projected travel demand of 6,000 vehicles per day, the Nevada Department of Transportation's Board of Directors approved a design-build project to complete the southern extension of USA Parkway in an expedited manner, two years earlier than projected.[18] The project, which involved NDOT taking over USA Parkway for $43 million and upgraded to highway standards, was planned for completion in December 2017 and was expected to cost between $65 million and $70 million. The funds to fast-track the USA Parkway build-out were obtained by deferring maintenance projects on seven low-priority northern Nevada highways.[19][16] The contract price was $75.9 million.[20] 80 workers were on site 24/6 building the road in stages,[21][22] with paving started in October 2016.[23] A two-lane roundabout was built at US 50.[24][25] The I-80 ramps were also improved due to heavy traffic.[26][27]

At a ribbon cutting ceremony held on August 28, 2017, in anticipation of the completion of construction, Nevada Governor Brian Sandoval bestowed the honorary name of "Infinity Highway" upon USA Parkway.[28] The extension opened for access on September 8, 2017, on budget and three months ahead of schedule.[29]