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NEW CASTLE, Pa. (KDKA/AP) — Drivers planning to use parts of the Pennsylvania Turnpike this weekend are going to want to make some alternate plans.

A major closure is underway this weekend, and if you forget, you could be sent on an 80-mile detour that will add at least an hour to your drive.

“Please plan accordingly, and if at all you can avoid that route and that travel this weekend, we’d appreciate it,” said Turnpike CEO Mark Compton.

The detour will run from 9 p.m. Friday and 4 a.m. Monday as crews close the toll road between the New Castle and Cranberry interchanges. That’s being done so crews can demolish and replace the Brush Creek Bridge in New Sewickley.

Turnpike spokesperson Carl DeFebo tells the “KDKA Morning News” that the Accelerated Bridge Construction technique they are using will drastically reduce construction time.

“Crews will demolish the old bridge and then slide the new bridge sections into place, and basically, we end up with a new bridge in one weekend instead of a year to a year-and-a-half,” said DeFebo.

Listen to the full interview here:

But the closure also means motorists who try to use that stretch of turnpike will be detoured onto Interstates 376, 80 and 79 to get around it.

The detour routes are marked for through and local traffic, but drivers are urged to pay close attention to the orange and black directional signs.

Motorists are urged to avoid that stretch of turnpike this weekend, but especially during peak travel hours, because major delays are expected. The detour could add more than an hour to travel time.

The New Castle interchange, Exit 10, and Cranberry, Exit 28, are about 18 miles apart.

For more information, visit the Pa. Turnpike’s website here.

(© Copyright 2017 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)