Expect some big delays and closures if you need to take Interstate 25 through the north part of the Denver metro area during the evening hours next week.

The Colorado Department of Transportation is doing night work on the highway between 136th and 120th Avenues starting Monday night – and it will require some full closures.

Southbound I-25 will be closed at 136th Avenue Monday and Tuesday nights, CDOT said in a news release.

Also on Tuesday night, the left two lanes of the northbound stretch of the highway will close at 120th Avenue. That means only one lane will be open.

Then, on Wednesday and Thursday nights, CDOT says crews will close northbound I-25 at 120th Avenue. Also on Wednesday night, expect the left two lanes of southbound I-25 to be closed at 136th Avenue.

This is all part of a $97.5 million project aimed at extending the Express Lanes from 120th to E-470.

All of this week’s road work will occur between 10 p.m. and 5:30 a.m., according to CDOT. Here are the detours, which will have an estimated 25 minute delay:

-For southbound I-25 traffic: Head west on 136th Avenue to southbound Huron Street, then left onto eastbound 120th Avenue back onto I-25.

-For northbound I-25 traffic: Take eastbound 120th Avenue to northbound Washington Street, then turn left onto westbound 136th Avenue before getting back on I-25.