Cops vs. machines
When Copley, Ohio, police officer Christopher Santimarino was first asked in court how fast his radar showed Mark Jenney's SUV was traveling the day he pulled Jenney over, Santimarino said 82 miles per hour. On cross examination, he said the figure was 83. Because of that inconsistency and Santimarino's failure to produce documentation for the radar readings at trial, an appeals court threw out the radar evidence.
But the court still upheld Jenney's conviction. Santimarino testified that based only on what he could see with his own eyes, he had been trained to estimate a vehicle's speed within four miles per hour. Five members of Ohio's six-judge supreme court said that was good enough for them: "We hold that a police officer's unaided visual estimation of a vehicle's speed is sufficient evidence to support a conviction…if the officer is trained…and is experienced in visually estimating vehicle speed."
The opinion doesn't just accept the proposition that it's possible to train human eyes to do the work of digital radar. It assumes that officers are incapable of exaggerating on the witness stand. As Justice Terrence O'Donnell explained in his lone dissent, in ruling that officer testimony is per se evidence of guilt, the court dispenses with the idea that, as with other witnesses in a trial, an officer's credibility should be evaluated by a judge or jury.