[fr_freak]

The point is that these problems would be absolutely no different from the current situation. Who's to say the officer isn't lying about what the radar said? It always comes down to his testimony anyway, whether there's a radar involved or only his estimate.

True, but I wasn't really concerned about the cases where a cop would lie about speeding (I suppose I was giving cops the benefit of the doubt in that most wouldn't purposely lie about speeding). I was thinking about the much higher rate of mistakes that would occur with eyeballs only.

[TChris]

I was thinking about the much higher rate of mistakes that would occur with eyeballs only.

It's true that his visual estimate isn't going to give the accuracy of a radar lock. Any officer who gave anything more specific than a range ("The vehicle appeared to be traveling approximately 45-50 MPH") would be questionable.

But specifying an exact speed isn't required to show a vehicle was over the limit. If the officer can say that he's certain, based on his estimation, that the vehicle was not traveling at or below the speed limit, but some significant rate higher, then it would be enough.

So it would be a "mistake" only if the officer was far enough off that a vehicle he estimated was speeding was actually not. Given that most LEOs don't write citations until you're going well over the limit (10-15 MPH over is common), and that estimating a vehicle's speed to within +/- 5 MPH isn't terribly difficult for an experienced traffic cop, that's a pretty unlikely mistake.