CHEYENNE - The Wyoming Department of Transportation is proposing a major reconstruction of the I-80/I-25 interchange in Cheyenne.

With an estimated cost of $220 million, the improvement would be the most expensive single roadway project in state history, according to WYDOT.

WYDOT officials released a study Wednesday outlining the need to increase safety and make room for anticipated traffic growth on the interstates. The cloverleaf interchanges were built in the mid-1960s, when standards were different than they are today, a WYDOT official said.

Between 2001 and 2006, there were 562 reported crashes resulting in 202 injuries and one fatality on the interstates in the Cheyenne area - a rate double the state average.

Both I-80 and I-25 are major national freight routes and are important for regional economic development.

Semi-trailers, meanwhile, were involved in 39 percent of the total accidents and truck traffic is expected to increase in the future.

The next step will be public hearings on the plan and a year long environmental study.

The earliest the project could begin is 2012 or 2013. It will take five or six years to complete, officials said at a press briefing Wednesday afternoon.

The department will need money from federal, state and local development sources, said Kenneth McHenry, associate project manager with CH2M Hill, which conducted the study.

The response from the business community, he said, has been positive.

Jay Gould, the department's engineer for district one in southeast Wyoming, said the federal transportation bill is coming up for continuation in Congress, which will offer an opportunity to request earmarked funds for the project.

"The critical next step is to try to identify those funding sources to move ahead," Gould said.

Factoring in an 8 percent inflation rate, the project will cost $350 million in six years, officials said.

The department, meanwhile, needs $250 million more than the current budget to keep up the current highway system. The Legislature last winter allocated $200 million for highways and roads for the two-year biennium.

"So we're still looking for special funding," Gould said.

Local interchanges at Lincolnway, Roundtop Road and Missile Drive are included in the plan.

Plans for improvement need to be secured before the land along the interstate is developed for other purposes.

The goal of the project is to provide the best infrastructure for development.

"In Cheyenne, the open areas to the west and the east appear to have the greatest potential. We need to coordinate with developers before that begins so we aren't stepping on each other's toes," Gould said.

WYDOT will hold the first public meeting on the proposed interchange improvements on Sept. 18 from 5 p.m. to 7 p.m. at the Hitching Post in Cheyenne.

Contact Joan Barron at (307) 632-1244 or joan.barron@trib.com