On Tuesday, Gov. Scott Walker announced plans to try to turn state Highway 41 from Milwaukee to Green Bay into a new interstate.

The upgrade would need a green light from the Federal Highway Authority, which would also determine the number of the new highway.

Until then, the Wisconsin Department of Transportation would begin work on upgrading the 142-mile section to interstate standards, at an estimated cost of $15 million to $20 million. The improvements would involve installing cable guardrails along some mediums and widening shoulders.

The new highway would run from Milwaukee’s Mitchell Interchange on I-94 to where Highway 41 connects with I-43 in Green Bay. The state hopes to have interstate signs up on the highway in 2015.

Upgrading Highway 41 would provide economic benefits to the state, Walker said in a press release.

“US 41 connects crucial regions of Wisconsin with economic impacts that benefit local, state and regional economies,” Walker said. “Converting the corridor to an Interstate highway will provide enhanced safety, mobility and economic development potential.”

Plans for the upgrade have been in the works at the Department of Transportation since 2005, when U.S. Rep. Tom Petri (R-Fond du Lac) added a provision to a transportation bill designating the segment as an interstate once federal requirements were met. Petri represents much of the area the highway runs through.

“The Milwaukee to Green Bay corridor and the Fox Valley are major centers for economic growth and employment in Wisconsin, and the entire area deserves the infrastructure necessary to support the businesses there,” Petri said in Walker’s release.

Environmental group 1,000 Friends of Wisconsin criticized the plans in a Milwaukee Journal Sentinel article, saying the widened shoulders could be costly. Walker’s move allows for the completion of the required Environmental Impact Statement, which will take several years. The study process for the statement allows the public to share views on the project.

At a time when budget cuts are the primary focus in light of government deficits, the project is a necessary investment, said Richard Robinson, an associate professor of marketing.

“Clearly, in this era of budget cuts, transportation warrants our attention as a top priority in a state that depends so heavily on tourism and ‘through-travel,’” Robinson said in an e-mail. “This project provides employment and other economic value added to a state sorely in need of positive steps.”

Expansion and reconstruction efforts on sections of US 41 in Winnebago and Brown counties are already underway, and are scheduled to continue into 2017. Walker’s release said the project is an investment of about $1.5 billion in Wisconsin’s transportation system. The new highway will be Wisconsin’s first interstate since 1996, when Highway 51 between Portage and Wausau was upgraded to I-39.

But the interstate designation may not mean all that much, said James Crovetti, an associate professor of civil and environmental engineering and director of the Transportation Research Center. Crovetti said US 41 already meets many of the standards for an interstate.

“It will give a more efficient flow of people and goods, less interruptions,” Crovetti said. But it’s essentially at an interstate level of service (already).”