I was listening to this on the AM radio earlier this week. I can see both sides:
1. The cops look at cars on the highway all day - it's a big part of their job to monitor traffic speed. They took a course which trained them to detect speeds just by eyesight alone. It would be the same as a Jeweler who appraises diamonds or an audio engineer who can localize frequencies on the sound spectrum. The cops are trained to detect the speed of the car in between 3-5mph accuracy. That's pretty good. And if the car is going 90 mph, it doesn't matter if the cop is 5mph off because the driver is still breaking the speed limit.
2. At the same time, we should never go on the validity of one's word these days - too much temptation for people to go bad. It is a breeding ground for corruption and here's how - If a cop can stop someone and give a ticket solely on his own opinion of speed, who's to say that he won't "fudge" his opinion when he needs to meet a quota? Beyond that, if the cop is indeed desperate to get his quota filled, he might become overly sensitive in his judgement, giving tickets to those who may only be going 3-5mph over the limit, which would still be generally legal if it's with the flow of traffic.
At the end of the day, let the unbiased equipment be the determining factor. We get too loosey-goosey when we take one man's word over another, especially when it gets into a one-on-one court case like this. Who's right? Well, the cop has to be because he's a cop. Yeeeaaah, not a fan of that one.
