Two Highway 12 intersections east of Pasco with a history of injury and fatality collisions will change drastically by spring 2012.

Preparatory work to replace the Highway 124 and Humorist Road intersections with bridges started this week.

The $22.2 million project is part of widening Highway 12 to a four-lane corridor between Walla Walla and the Tri-Cities.

Jim Kuntz, Port of Walla Walla executive director, said the stretch of Highway 12 through Burbank has been the site of too many serious accidents.

"As far as I am concerned, the interchange can't be built soon enough," he said.

After construction, Highway 124 will go over Highway 12 on a bridge and connect to Highway 12 with ramps, forming a new interchange, said Moe Davari, state Department of Transportation project engineer.

The ramps will connect to Highway 124 on the north and to Fifth Street to the south using single-lane roundabouts, he said. Humorist Road no longer will connect to Highway 12, he said. Instead, an overpass will route traffic over the highway.

Jantz Road will be extended west to connect to Fifth Street, Davari said, to provide access to Highway 12 for traffic on Humorist Road.

About 16,000 vehicles, including 1,000 trucks, travel Highway 12 daily in that area, Davari said.

The project is designed to reduce collisions and fatalities, he said, on roadway widened to four lanes in 2005. The revisions will mean that vehicles will no longer cross traffic at the two intersections.

There have been two fatal collisions at each intersection in the last decade, said Washington State Patrol Lt. Roger Wilbur. Those collisions include the 2008 death of two Burbank teens, the 2007 death of a Walla Walla sheriff's deputy and fatal collisions in 2002 and 2010.

Each intersection had seven collisions last year, Wilbur said. And there were 23 collisions on Highway 12 between the Snake River bridge and the signals at the Highway 124 intersection.

Those 37 collisions aren't many compared with the 1,758 collisions the state patrol responded to in the Tri-City area last year, Wilbur said, because that part of Highway 12 doesn't get much traffic. But with traffic crossing the roadway, there is potential for tragic accidents, he said.

Although safety was the prime reason for the project, Kuntz also expects the work to improve the region's economic draw.

Kuntz said the four-lane corridor will make it easier to attract businesses because they consider highways when evaluating where to move.

The Port of Walla Walla owns 150 acres south of Highway 12 between the two intersections. "Right now, all it is is an open field," Kuntz said. "But the port has big plans."

It wants to open a business park there and attract commercial, light industrial and warehouse businesses, he said.

The port has led lobbying efforts of 30 public agencies and private businesses in the Highway 12 Coalition, winning $127 million in state and federal money for Highway 12, Kuntz said.

The group formed in 2001 wants Highway 12 to be four lanes between Walla Walla and the Tri-Cities to improve safety and boost the economy, Kuntz said. So far, 18 miles have four lanes, with 24 miles still two-lane highway.

Kuntz said collisions in the four-lane segments dropped by 13 percent in the last four years.

The interchange and bridge project will be paid for with state gas tax revenue, Davari said.

Highway 12 will remain open during construction, with the existing intersections removed when the project is done, he said.

Lane closures will occur during construction but not during peak traffic times of 5 to 7 a.m. for eastbound traffic and 3:30 to 6 p.m. for westbound traffic, he said.

Lead contractor Selland Construction of Wenatchee will work at night to minimize the impacts, Davari said.

There will be five closures requiring detours, he said. They include closing part of Fifth Street, Highway 12 eastbound and westbound when bridge girders are installed in July at Highway 124 and Humorist Road, Davari said. The bridges will be built simultaneously to speed the project.

Most work is to be completed this year, with the last part finished next spring.

Kristi Pihl: 582-1512; kpihl@tricityherald.com