Petrino acknowledged that he had a "previous inappropriate relationship" with the passenger, Jessica Dorrell, who was was hired last month as the student-athlete development coordinator for football.
Through a statement released by university officials, Petrino had initially claimed that he was alone when he had crashed. Petrino is married and has four children.
"My concern was to protect my family and a previous inappropriate relationship from becoming public," he said in a statement. "In hindsight, I showed a serious mistake in judgment when I chose not to be more specific about those details. Today, I've acknowledged this previous inappropriate relationship with my family and those within the athletic department administration."
After a police report was released Thursday that confirmed that Dorrell was on Petrino's bike, Arkansas Athletic Director
"I'm at the beginning of the review. I don't know what I'm going to find," Long said. "I hope to have a resolution soon. I certainly don't have all the answers here tonight, as we meet. But again, I have an obligation and responsibility to obtain the information and then act appropriately on that information."
In his four seasons with the Razorbacks, Petrino has amassed a 34-17 record and helped turn the team into a national contender. Arkansas finished last season ranked No. 5 after losing only to national champion Alabama and runner-up LSU.
In his statement, Petrino made clear that he would like to remain the team's coach.
"I will fully cooperate with the university throughout this process and my hope is to repair my relationships with my family, my athletic director, the Razorback Nation and remain the head coach of the Razorbacks."