And I got out of what would have been a very expensive ticket. It was one of the few times I ever got to use my engineering degree.
The only reason I was able to prevail (without getting into details) is I had witnesses in several other cars at the intersection that gave me the necessary "data points", under oath, that I needed to plug in the equations.
I won't say that the judge actually understood the math I presented, because I'm sure he didn't, but I was able to demonstrate why the officer's statements couldn't be accurate. That was good enough to get off in this particular case.