DENVER - Xcel Energy says an emergency repair will temporarily delay traffic even more on one of Denver's busiest streets.

Crews are working to replace a concrete steam vault under downtown Denver that could pose a dangerous problem for drivers.

Xcel's Michelle Aguayo says the underground vaults are old and deteriorating. The emergency situation was discovered on Wednesday.

Two lanes on Speer Boulevard and one lane on Stout Street will stay closed until repaired are completed.

According to Aguayo, the road could collapse if the vault isn't repaired. The repair is expected to last until next Wednesday with crews working throughout the weekend. The vault under Speer is one of the larger ones in Denver.

Crews have to build a concrete building of sorts underground which is extending repair times.

Many drivers noticed an even longer commute but did not understand why.

"I thought it was just more construction," says driver Leo Cobb.

9NEWS journalist Brooke Way's commute from Speer and Logan to the Highlands took an hour Thursday night.

Xcel says drivers should be patient and understand there are no alternatives.

"It makes their commute much longer and we know that is frustrating," Aguayo said.

Drive times are often doubling and sometimes tripling, according to drivers.

Xcel says this is a routine process and around 10 vaults are repaired in a similar way every year. Aguayo adds, this repair may be extra frustrating considering the location and size of the vault.