Traffic on Interstate 84 through Ladd Canyon will be slowed by a rock blast early Wednesday evening.

The rock blast, set for 6 p.m. Sept. 3, will be conducted as part of the Oregon Department of Transportation’s $30 million Ladd Canyon Freight Improvement Project.

Traffic in both directions, from the west side of Ladd Canyon and for about 2 miles east, will be impacted by the blast work, according to Mike Remily of ODOT, manager of the Ladd Canyon project.

“A ‘rolling slowdown’ will take place on both directions of I-84 starting at 5:40 p.m. to create a 20-minute gap in traffic for the blast to be safely conducted and the freeway cleared of any debris,” Remily said. “The freeway will not be closed, but (traffic) may be backed up for a short time period.”

The motorists affected will be those driving eastbound from the Perry exit and westbound from the Clover Creek exit, 9 miles east of the Reynolds Rest Area. These drivers will have to follow pilot cars traveling 30 miles per hour between 5:40 p.m. and 6:10 p.m., according to ODOT.

The blast will be part of the work being done to replace a bridge with a concrete box-like structure. The box will be large enough to accommodate log trucks and semi trucks. Those driving on it, after it’s finished, will feel like they are driving under a tunnel, Remily previously told The Observer.

Eliminating the existing bridge will be beneficial because it tends to get icy which has long posed a problem, according to ODOT. The concrete box is being installed as the bridge is being taken out and should be in by the end of October.

Two portions of the Ladd Canyon Freight Improvement Project have already been completed this year.

One, finished in June, involved widening the fast lane shoulders from La Grande to Ladd Canyon, a distance of about 7 miles.

The expanded shoulders, which are now 7-feet wide, provide more space for drivers to pull over during emergencies and make it less likely they will accidentally roll off the freeway. Remily said the expanded shoulders will be a big help when ODOT has to close the east and westbound slow lanes to do maintenance work. All slow-lane traffic will be diverted to the fast lane, where the additional space will accommodate more vehicles. This will also make things less hazardous for maintenance workers.

The second portion of the project that has been completed is the repaving the Exit 265, about 5 miles east of Ladd Canyon. Remily said the Exit 265 roadway was badly in need of repair because it was cracked and rutted.

ODOT will conclude work on the Ladd Canyon Freight Improvement Project in late October and resume it in 2020 on April 8. The spring work will include the addition of a 1.5-mile third lane on I-84 from Milepost 269.5 to Milepost 271. The new lane will be meant for trucks. The expanded space should reduce the number of times Ladd Canyon has to be closed due to trucks blocking lanes, Remily said.