SALT LAKE CITY — An audit into the state's transportation agency over the controversial awarding of the billion-dollar-plus contract for the I-15 CORE project has been delayed.

Initially scheduled to be complete by the end of November, State Auditor Auston Johnson said he needs more time to get it done and that interviews of the large number of people who were involved in the I-15 CORE selection process are taking longer than initially expected.

"The interviews take a while," Johnson said. "I really think we're looking more at the end of December."

Gov. Gary Herbert requested the audit of UDOT in late September as controversy raged over revelations about the bid for the $1.7 billion I-15 CORE project — Utah's biggest-ever road contract.

He specifically asked the auditor to examine UDOT's processes for awarding contracts, technology usage and human resource management practices.

"I'm confident the audit will show things as we've described them," said UDOT deputy director Carlos Braceras. "I'm hopeful that the audit is able to help us find opportunities to improve processes, to make things better in the future."

Johnson has assigned four investigators who are all CPAs and certified fraud examiners.

They're interviewing dozens of people, including the technical team, the oversight review committee, UDOT executives, and the winning and losing bidders.

"Was this bid handled differently?" Johnson asked. "If it was, was it because of pressure, or was it because it was just a new way of bidding jobs, which this one was?"

Another question the process raised was why a UDOT selection review committee picked Provo River Constructors — by one point — when the technical team favored second-place bidder FSZ?

"We're not going to try and duplicate the selection process," Johnson said. "What we really want to look at is the adjustments that management made at the end, and see if those stand up."

Also, why did UDOT pay out a $13 million settlement to a losing bidder, doing it without notifying top state leaders including the governor?

"I personally think if I had a request to write a check for $13 million, I'd probably want to run it by somebody," Johnson said, while noting UDOT was exempt from a state requirement that agencies notify the top levels of state government about large legal settlements.

Johnson's office has subpoena power.

"We're always ready to use it," he said. "We haven't used it yet, and I don't anticipate we will use it, because they've been very cooperative."

Johnson said his office has not uncovered anything illegal to date but has uncovered some surprises he won't yet reveal.

"We're going down some trails we didn't know that were there before," Johnson said.

The audit will examine any impact on the bid process of an "improper relationship" between road builder Guy Wadsworth, a leader of the PRC team, and a senior female UDOT staffer.

But it will not be looking into $87,500 in contributions to the governor's campaign by PRC.

The auditor says election complaints are the responsibility of the Lieutenant Governor's office.