After a Monday morning meeting, leaders with the California Department of Transportation issued an apology to the thousands of drivers who were stuck in a massive traffic jam on Interstate 10 near Palm Springs.

"CalTrans extends their apologies to the motoring public for the lengthy traffic delays that were encountered on westbound Interstate 10 in the Eastern Desert on Sunday, February 12," according to the news release.

The back-up started Sunday morning when a project underway to repair broken concrete on the freeway took longer than the cement company estimated.

"The concrete being utilized to make the repairs requires four to five hours to cure before traffic can be permitted to drive on it," CalTrans said in their public statement. "A breakdown at the nearby batch plant contributed to delays in completing (the) project and reopening lanes before the work schedule ended at 7 a.m. Unfortunately, the various slabs targeted for replacement had been removed and prepared for the material before the breakdown at the batch plant occurred, resulting in the continued closure of lanes outside the work schedule."

All lanes weren't opened on the freeway until 9:30 p.m. by CalTrans' estimates. Local media weren't notified until shortly before 11 p.m.

Drivers complained after they waited upwards of four hours to drive 20 miles from Indian Canyon in Palm Springs to Hargrave Avenue in Banning, especially when some of them said they saw no activity in the work zone.

"The crews were awaiting the delivery of the material to finish the work and then for the new pavement to set," CalTrans explained.

CalTrans leaders said they are investigating the chain of events that led to the backup.

They also said they're taking measures to ensure another crippling backup doesn't happen again, although they didn't provide specifics.