City police said the 63-year-old mayor was pulled over Wednesday night after an officer saw a vehicle cross the center line and then move into a designated bicycle lane.
An officer reported a breath test produced a blood-alcohol level of 0.12 percent, exceeding the state's threshold of 0.08 percent. Estes was held in the county jail until he was released after posting a $100 interim bond.
Estes' next court appearance is Nov. 4.
Estes is seeking a second two-year term in the Nov. 5 election. He said he "really screwed up," and hasn't decided whether to remain in office or continue his re-election bid.