TAMPA — One February afternoon two years ago, a Tampa police officer pulled over Ronald Ayers on Gandy Boulevard.

The traffic stop led to a DUI arrest after the officer decided that Ayers, who was 73 at the time, had alcohol on his breath, slurred speech and performed poorly on field sobriety tests. But when Ayers got to the county jail, records show, a breath test put his blood alcohol level at 0.000. A urine test turned up no intoxicants.

Prosecutors eventually dropped the DUI charge. Now the Lakeland resident is suing the city, accusing the officers and the Tampa Police Department of false arrest and malicious prosecution.

The lawsuit, filed April 29 in Hillsborough circuit court, claims Tampa officers pressured to meet annual DUI arrest quotas make unconstitutional arrests without sufficient probable cause. Those same allegations form the basis of an ongoing lawsuit by prominent Cuba activist Al Fox, who was arrested and charged with DUI in February 2013 despite clean urine and breath tests.

"We are in no way, shape or form against DUI enforcement, but the problem we've seen repeatedly is that DUI (officers) are going way overboard to enforce the law," said Joseph Lopez, a Tampa attorney representing both Ayers and Fox. "And this is a perfect example of that."

Tampa police spokesman Steve Hegarty said the department does not comment on pending litigation.

According to an arrest report, Officer Matthew Belmonte saw Ayers make a right turn from Manhattan Avenue to head west onto Gandy Boulevard about 3 p.m. on Feb. 3, 2014, causing westbound traffic to "take evasive action."

Belmonte wrote that Ayers was slurring his speech, had red and glassy eyes and the odor of alcohol on his breath. When the officer asked Ayers if he had been drinking, Ayers said he'd had one beer. He said he felt fine and had no physical disabilities but was diagnosed with dementia and was not taking medication for it, according to the report.

"He was able to tell me what day it was, that he was by the old Winn Dixie on Gandy (a correct statement) and that he was going to the dog track in St. Petersburg," Belmonte wrote.

There's no way he could have had alcohol on his breath "from the very small amount of alcohol he had consumed much earlier in time," the lawsuit states. Ayers had one beer at Brick House Tavern on N Dale Mabry Highway about two hours earlier, said William R. Gower III, another attorney representing Ayers.

A recording of the stop shows his speech was not slurred, according to the complaint. But Belmonte and Officer Jacquelyn Zambito made Ayers perform field sobriety exercises despite his age and the fact that Ayers told Belmonte he has dementia, according to the suit.

Ayers staggered, swayed and failed to follow instructions during walk-and-turn, one-leg-stand and finger-to-nose exercises, Belmonte wrote.

The suit claims the officers should have known that research shows those exercises are not a reliable way to determine if someone Ayers' age is intoxicated. Belmonte, who is now a detective, and Zambito could have called for a portable breath testing device but did not, according to the complaint.

"His failure was the result of his inability to appropriately maintain his balance and understand the instructions due to his age and physical and mental disability," the suit states.

Despite that assertion, Gower said Ayers was in the early stages of dementia and was "perfectly fine" to drive. Ayers' driving record shows his license was suspended for six months in 1992 after he was cited for DUI in Sarasota County.

Ayers had to post bail, pay to get his vehicle out of the impound lot and pay for an attorney. He is seeking damages in excess of $15,000.

The lawsuits by Fox and Ayers were filed after the department's DUI practices drew intense scrutiny.

A month before he pulled Fox over, DUI Sgt. Ray Fernandez was involved in the DUI arrest of Tampa lawyer C. Philip Campbell after Campbell left a downtown steak house. The sergeant had been tipped off by a close friend who worked at Adams & Diaco, the law firm Campbell was battling in court at the time. Prosecutors who investigated later called the arrest a set-up involving a female paralegal from the firm and dropped the DUI charge. Fernandez was fired.

An outside review team did not find evidence of "inappropriate targeted or selective enforcement" and said there were no "red flags that would suggest any other substantial failure in the practices of TPD." But in January 2014 — about two weeks before Ayers' arrest — then Chief Jane Castor announced changes to how the department handles DUIs. Among them: more thorough individual investigations rather than relying on language often seen in DUI reports, such as "slurred speech," "odor of alcohol" and "glassy eyes."

Times senior news researcher John Martin contributed to this report. Contact Tony Marrero at tmarrero@tampabay.com or (813) 226-3374. Follow @tmarrerotimes.