The Lopresti trial, being heard before Justice James M. Kindler, may serve as a cleaner test of how much ticket-fixing matters to jurors. There are additional witnesses, including the minivan driver and technical experts, as well as other issues the defense is raising about divergent statements by Officer Goris, and the adequacy of the blood-alcohol-level test. But the trustworthiness of the two officers is the foundation of the case.

Mr. Lopresti, who had an earlier conviction for driving while intoxicated, was arrested in December 2006 after colliding head-on with the Suburban, which was preparing to make a turn. He had been at a Christmas party at the Yankee Tavern, just down the block from the courthouse, and a place where Babe Ruth and Lou Gehrig once drank. He told the police he had had four or five Beck’s beers.

In his opening statement, Mr. Perlmutter advised the jurors that they would hear from “corrupt officers” whose words could not be believed.

During the cross-examination by Mr. Perlmutter on Wednesday, in addition to discussing the defendant’s ability to stand and whether Mr. Lopresti had had a “very strong” or “moderate” smell of alcohol on his breath, Officer Goris testified that she had gone to her union delegate, Jaime Payan, to get the ticket fixed for her boyfriend’s cousin. She said the delegate had said the worst that would happen was that the cousin might have to plead not guilty and the ticket would be taken care of before trial.

On another occasion, when her mother got a ticket, Officer Goris said, she accompanied her to traffic court, and when she spoke to a sergeant there, her mother did not have to pay anything.

Efforts to reach Mr. Payan late Wednesday were unsuccessful.

Harrington Marshall, a highway officer and 19-year police veteran who gave Mr. Lopresti the blood-alcohol test at a Bronx station house, began his testimony. At the end of her questioning, Allyson Kohlmann, an assistant district attorney, asked him about being caught on a wiretap seeking to get a ticket fixed.

He acknowledged that he had reached out to a colleague “for professional courtesy” to erase a summons, for a person he did not identify. Officer Marshall said he did not know whether he would be prosecuted for his conduct but did say he expected to be disciplined by the department at some point.