CABAZON -

Caltrans says it's still investigating the road project that triggered delays and a massive traffic jam that stretched for more than 20 miles and left travelers stranded for hours in the San Gorgonio Pass last Sunday.

The department also continues to apologize for what happened.

"We're sorry. We're doing everything we can to ensure this never happens again," said Caltrans spokeswoman Terri Kasinga.

But Caltrans also lays blame on Robertson's Ready Mix in Cabazon, accusing the company of failing to deliver concrete to the construction site on time.

"There were some issues at the batch plant with getting the correct product and having it be the correct portions for what was needed to backfill these holes," said Kasinga.

News Channel 3 tried to talk with someone at the Robertson's plant in Cabazon, but was told no one would be available for an interview.

Instead, Robertson's released a statement that read, in part, "The project was put on hold and our drivers stood on standby for six hours waiting for the okay to deliver concrete."

As the blame game plays out, Caltrans admitted its lines of communication failed and should have alerted drivers about the delays.

"So it's important to continue with these projects, but we do need to notify people. That's going to be first and foremost, and any other issues we can address to make it better for everyone -- that'll happen," said Kasinga.