State Route 439 (SR 439) is a four-lane state highway in Lyon, Storey and Washoe Counties in Nevada. Better known as USA Parkway, the route connects U.S. Route 50 (US 50) in Silver Springs to Interstate 80 (I-80) in Clark via the Tahoe Reno Industrial Center (TRIC). The northern portion of USA Parkway was initially constructed by the industrial center's developers; however, the Nevada Department of Transportation (NDOT) agreed to assume control of the road after Tesla announced plans to build its Gigafactory at TRIC in 2014. NDOT opened the extension of SR 439 south to US 50 in Lyon County on September 8, 2017. Route description SR 439 serves as a four-lane highway connector of I-80 and US 50. The south end of the highway is at a roundabout with US 50 west of Silver Springs, near Silver Springs Airport in Lyon County. From there, the road heads northwest into mountainous terrain, providing access to the Tahoe Reno Industrial Center and the Tesla Gigafactory. The highway continues to its end at a modified diamond interchange with I-80 located approximately east of Sparks, in Washoe County. History The owners of the Tahoe Reno Industrial Center constructed the 6-mile USA Parkway between I-80 and TRIC for $60 million in 2001 specifically to provide access to TRIC (touted as the largest industrial park in the United States) in Storey County. As of August 2009, it was reported that of roadway had been completed—the southernmost to the Lyon county line had only been graded and were still awaiting pavement—while roughly of the route to reach US 50 remained unconstructed. Expansion plans As the plans for TRIC were realized with many large companies moving in, 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 . The connection to Silver Springs would increase regional mobility and provide air-freight shipping possibilities at nearby Silver Springs Airport. 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