RENO, Nev. - The Federal Highway Administration has approved plans for $1.5 billion in improvements to a major interstate interchange and more than a dozen highway exits in Reno and Sparks over the next 20 years.

The agency issued a final environmental impact statement and record of decision selecting the alternative preferred by state transportation officials to reconfigure the Spaghetti Bowl intersection where I-80, I-580 and U.S. 395 meet east of downtown Reno.

The project is intended to improve safety and reduce travel times in the metro area where the population is expected to grow 27% the next two decades.

The highway administration said the project's biggest downside is that 326 residences and 22 commercial businesses eventually will be displaced.

But it said the alternative selected is "environmentally preferred," received the most support from the public and improves freeway traffic speeds and delays as well or better than the other twos.

It "strikes the best balance of satisfying the project needs while maintaining freeway access and minimizing impacts," the administration said.

Nevada Department of Transportation Director Kristina Swallow said the 28 months it took NDOT to complete the impact statement was the fastest in the agency's history and one of the fastest in the nation for a project of this size.

"Working alongside the community and our partners, NDOT is dedicated to making interstate improvements that will keep the community safe and connected for decades to come," she said.

The Reno-Sparks population has quadrupled since the interchange was originally constructed in the 1960s and 1970s.

The 260,000 vehicles that passed through the Spaghetti Bowl daily in 2016 is expected to grow to 330,000 in 2040. Without future improvements, travel delays are expected to increase by 53%, NDOT said.

The interchange and connecting highway segments have higher crash rates than similar urban freeways in Nevada, the department said.

The plans call for higher-speed, direct-connect ramps with speed limits up to 50 mph (80 kph) to help improve the flow of traffic and minimize merging and weaving.

Overall, NDOT plans to construct, replace or widen more than 60 bridges that are at or approaching the end of their planned service lives. The agency says many of the existing bridges are not wide enough to meet its standards for traffic lane and shoulder widths.

The project will be completed in phases, beginning next year with realignment and widening of eastbound I-80 lanes between downtown Reno and the Spaghetti Bowl. That's expected to take two years and cost $150 million. No residences or businesses will be relocated in the first phase.

The second phase slated for 2023-25 includes the acquisition of property in Sparks for work on I-80 east of the Spaghetti Bowl to East McCarran Boulevard.

News from © The Associated Press, 2019