But doesnt the criminal justice system recognize that even good cops can make honest mistakes?
A. Not really. Even though any sane individual can recognize that any system which relies on human beings is subject to error, the cost of factoring this error into individual cases on the traffic docket is too high for the system to bear. If our hypothetical honest traffic cop makes a mistake only one percent of the time and he writes a dozen speeding tickets per month, then one or two people every year will be unfairly convicted. The trouble is determining which one or two are actually innocent. The police officer will not admit to having made a mistake and clocked the wrong vehicle. After all, if he thought he clocked another vehicle, he wouldnt have written you the ticket. This situation yields the rather stark choice of either convicting everyone or no one. While it is an old legal maxim that the law prefers to let a hundred guilty men go free than to convict one innocent man, thats just not how it works in practice.
