The Washington state Department of Transportation plans on making Interstate 90-Medical Lake interchange improvements a higher priority when considering state fund disbursement due to an increase in business development near there, says Keith Metcalf, the agency's Eastern Region administrator.

The Medical Lake interchange has been moved up, behind the North Spokane Corridor on the funding importance list, jumping ahead of I-90 improvements between the Barker interchange and Liberty Lake, Al Gilson, spokesman for the Department of Transportation Eastern Region says.

The DOT chose to move the Medical Lake interchange up in priority for funding because of the growing aerospace effort and other new developments on the West Plains, near Airway Heights and Spokane International Airport, Metcalf says.

With those developments, Metcalf says the traffic demands on the Medical Lake interchange would be significantly higher than originally anticipated back in 2010 when a DOT study was completed for that interchange.

The initial plan called for realigning the westbound on- and off-ramps with Geiger Boulevard, bringing ramps to an intersection with Geiger, Gilson says. Original plans didn't address the overpass at all.

"We're only funded through partial design," Metcalf says, adding that the continuation of the project is dependent on potential funding from the state.

Gilson says the Eastern Region DOT office has submitted its budget to state DOT headquarters in Olympia. He says agency representatives there either are in the process of submitting the budget to the state Office of Financial Management, which is responsible for state budgeting and policy, or already have done so. The budget will be reviewed further by the Governor's office.

Metcalf says one option the DOT is considering for the Medical Lake stretch is what's called a divergent diamond interchange. That design allows traffic that typically would have to make a left-hand turn to exit or enter the freeway ramp the ability to do so without having to cross traffic. He says the traffic revision allows for more free-flow access on to ramps, without making motorists negotiate oncoming traffic. Gilson says there are no interchanges of that type in the Spokane area and he doesn't believe there are any in the state.

"We have some analysis to do first, but we see some advantages in that type of design," Metcalf says.

One new addition to the West Plains area is the large Caterpillar distribution center on Hallett Road. Caterpillar Logistics Services Inc., the Illinois-based subsidiary of construction and mining equipment behemoth Caterpillar Inc., built the 554,200-square-foot facility on a 72-acre site east of the Medical Lake interchange.

Along with Caterpillar, UTC Aerospace Systems, a company that makes carbon aircraft brakes is also located in the West Plains area, with Triumph Composite Systems Inc. in neighboring Airway Heights, which makes nonstructural aerospace products.

The DOT made improvements to the Medical Lake interchange in September 2008 that included extending the right-turn lane on the westbound off-ramp and allowed for an increased turn radius for large trucks on the north end of the interchange. The state agency says upgrades were needed to decrease congestion.

Metcalf says the DOT has identified needed improvements at the Geiger interchange as well. The interchange is in need of intersection improvements, and better on-ramp merging and lengthening to increase safety and allow for a higher traffic capacity. He says no plan has been solidified yet, but the agency is looking at the possibility of installing roundabouts.