If motorists who might use Interstate 70 haven't done so yet, they should start making detour plans for this coming weekend.

In order to drop a pair of bridges as part of the two-year reconstruction project at I-70 and Interstate 435, the Missouri Department of Transportation plans to close I-70 from the Missouri 291/I-470 interchange west to the I-435 interchange beginning at 9 p.m. Friday. That stretch of the freeway is scheduled to reopen by approximately 5 a.m. Monday.

Crews will be demolishing two ramps – the left-exit bridges from southbound I-435 to eastbound I-70 and from northbound I-435 to westbound I-70.

Those ramps will be closed beginning at 7 p.m. Thursday. They will be replaced long flyover ramps that exit from the right, opening approximately in the spring of 2020.

At about 7 p.m. Friday, I-70 will be reduced to one lane in both directions, and about 8 p.m. crews will begin closing all on- and off-ramps along that stretch of I-70.

Entrance ramps of eastbound I-70 to close include Manchester Trafficway, northbound I-435, Blue Ridge Cutoff, U.S. 40, Blue Ridge Boulevard, Noland Road and Lee's Summit Road.

Entrance ramps to westbound I-70 to close include northbound and southbound M-291/I-470, Lee's Summit Road, Noland Road, U.S. 40, and Blue Ridge Cutoff.

MoDOT spokesperson Lairyn McGregor said crews did discuss the possibility of allowing local traffic on westbound I-70 to exit at Lee's Summit and Noland roads, etc., and they were concerned about traffic overloading the system.

“Crews are concerned that through traffic would follow suit of the local traffic and take I-70 all of the way up to the closure and realize all too late that they couldn’t get any further down I-70,” McGregor said. “This would cause large backups along Lee's Summit Road, Noland Road or U.S. 40.”

Also, McGregor said, a complete closure allows crews to plenty of needed maintenance work on the highway, including lighting, drainage, median and pavement work.

Last year, when MoDOT closed I-70 for the same distance to drop the Crysler, Phelps and Pittman road bridges over the highway, crews finished quickly enough that the highway was reopened about a half-day earlier than scheduled.

Motorists shouldn't count on that this time, though. In addition to demolishing and cleaning up the ramps, crews will be doing drainage work that requires a saw cut across all of I-70 and then additional excavation and concrete work, McGregor said.

For long-term detours, motorists who need to access eastbound I-70 from southbound I-435 should take the westbound I-70 exit ramp, immediately take the U.S. 40 exit and then turn back east. Motorists who need to get onto westbound I-70 from northbound I-435 should exit at Raytown Road/Stadium Drive, turn north and follow Raytown Road as it becomes Manchester Trafficway, then turn west onto U.S. 40 and follow the detour to the westbound I-70. On Chiefs game days, through traffic should instead go to 23rd Street, exit and U-turn under the bridge and get back onto southbound I-435 to westbound I-70.