Drivers heading through Interstate 70’s mountain corridor into Idaho Springs on Monday night should expect delays as construction reduces the highway to one lane in each direction.

Westbound I-70 will shrink to one lane on the east side of the Veterans Memorial Tunnels starting at 5 p.m. while one lane of eastbound I-70 will close near mile marker 240 at 6 p.m., according to a Colorado Department of Transportation news release.

Westbound I-70 drivers will shift into the eastbound lanes and travel up the exit 241 on-ramp to cross over the highway on Colorado Boulevard and re-enter westbound I-70, the release said.

Eastbound I-70 drivers will exit onto the new off-ramp at Colorado Boulevard and proceed down the ramp to re-enter the highway.

All lanes are expected to reopen by 7 a.m. Tuesday, but the eastbound lane closure might be in place longer “to make the highway safe for travel,” the department said.

The detours are due to construction crews setting the girders for a new bridge under construction at exit 241, the release said.

Elizabeth Hernandez: 303-954-1223, ehernandez@denverpost.com or twitter.com/ehernandez