MIAMISBURG — A major portion of the multimillion overhaul of Interstate 75 through the region is nearing completion.

The section, in Butler County, has vexed drivers between Dayton and Cincinnati for three years and been the site of hundreds of injury crashes.

The overall project also includes rebuilding of Interstate 75 through downtown Dayton and ongoing work through Hamilton County and is meant to straighten and widen the region’s main artery for commuters, travelers and truckers.

The interstate work in Butler County is expected to be completed this week, according to the Ohio Department of Transportation. Another section, in Warren County, is slated to be done next summer. Renovation of those sections cost $216.8 million. Montgomery County’s portions don’t finish until next year and in 2013.

“When you add up all the work that’s going on in Dayton, in the Middletown area, then some in Hamilton County and further south to the Brent Spence Bridge across the Ohio River, those are huge investments,” said Bob Koehler, deputy executive director of the Ohio Kentucky Indiana Regional Council of Governments.

“The I-75 corridor is a significant corridor because it connects Detroit to Miami and all the trade that comes through there, and all the commuter traffic that it carries...”

The work, Koehler said, will help spur economic development near the corridor — from Butler County’s Liberty Way in the south to Montgomery County’s Austin Boulevard.

“I think it’s obviously providing the connections between those areas that are growing together anyway and it’s opening up an enormous trade corridor and economic development corridor,” Koehler said.

Since the project was announced, three hospitals have opened within two miles of the highway in Butler and Warren counties and a 400,000-plus square foot outlet mall opened off I-75 in Monroe between the three health care facilities.

In the past three years, the four-mile stretch of interstate between Ohio 63 and Ohio 122 has seen nearly $1 billion in investment, according to Chris Dobrozsi, vice president of real estate development for Al. Neyer Inc.

“That whole I-75 corridor ...is really a catalyst for a lot more to come,” he said. “You need that investment of infrastructure and transportation to be able to make these things happen.”

The area is already experiencing job growth from the I-75 road improvements, said Martin Russell, director of the Warren County Office of Economic Development.

In 2010, he said, 1,709 jobs were created in the two-county I-75 corridor.

Of that total, Russell said, 1,427 jobs were in the retail sector and 49 percent of those jobs were along Ohio 63, in Lebanon and parts going north in Warren County.

Twenty-six percent of those jobs were created in Franklin, he said.

Meanwhile, navigating through the ongoing lane closures, temporary lanes and the sometimes narrow roadway enclosed by concrete barriers has been a daily headache for the tens of thousands of motorists.

While transportation officials say completion of the construction will make the highway safer, there have been more wrecks along the interstate in Butler and Warren counties when compared to the years before construction began, according to the Ohio State Highway Patrol. There have been five killed in accidents in that section during the construction, two involving vehicles that rear-ended dump trucks.

The Butler County section of I-75 has up to 119,000 vehicles traveling it a day while the Warren County portion handles in excess of 97,000 daily, according to ODOT.

Work on the Warren County portion of I-75 is set to be completed next summer. The $113.7 million project calls for work on eight miles of pavement and the addition of one lane of traffic in each direction on I-75 from Ohio 122 to the Montgomery County line.

Motorists traveling much of the section now must contend with three lanes of traffic enclosed with concrete barriers on each side.

The project, which began in March 2009, also includes reconfiguring the Ohio 122 interchange, and replacing the I-75 overpasses at Ohio 122 and Ohio 73.

In Montgomery County, several road projects are under way:

• The modernization of I-75 through downtown Dayton project, which includes I-75 and Ohio 4 Phase 1A and Stanley Avenue, is a $157 million project that is scheduled for completion this fall.

New interstate lanes have been relocated and widened over the Great Miami River, and the capacity of the interstate has been increased with an additional lane in each direction.

The existing I-75 northbound lanes crossing the river have been reconstructed and utilized as ramps. Dayton’s Main Street is also being widened its entrance and exit ramps to the interstate are being improved.

Access is being provided to Ohio 48 from southbound Ohio 4 and Grand Avenue ramps are being combined with improved Main Street ramps.

In addition, the $17 million Stanley Avenue project includes removing circle ramps and ramps at Neva Drive and Leo Street, signalization at Stanley Avenue and constructing a standard ramp at Stanley to northbound I-75.

• Phase 1B of the project, which includes I-75 and U.S. 35, will decrease congestion and replace aging pavement and bridges along I-75 just south of the downtown area, officials said.

The $71 million project, scheduled for completion in June 2013, also will create three continuous lanes of traffic on I-75 in both directions from just north of the Edwin C. Moses exit to just north of Fifth Street in Dayton.

• The I-75 and South Dixie Drive and Central Avenue Interchange is under construction.

This interchange was originally designed as the northern border of a north-south limited access highway from Cincinnati to Dayton, ODOT officials said.

When I-75 was later extended to the north, the current partial interchange at Central Avenue and Dixie Drive remained.

The current configuration of the I-75 interchange with Central Avenue and Dixie Drive is missing four direct ramp movements and the intersection of Central Avenue, and Dixie Drive and Dryden Road is missing left turn movements, ODOT officials said.

These configurations require existing traffic to use complex and lengthy routes to reach businesses and residential areas, ODOT officials said.

Staff Writers Nick Blizzard, Kareem Elgazzar, Rick McCrabb and Justin McClelland contributed to this report. Contact this reporter at (513) 483-5219 or dewilson@coxohio.com.