[kelnos]

> "Why do you think I pulled you over?"

That's pretty standard; nearly every traffic stop I've witnessed or heard about contains that line.

I believe they do it because -- assuming you give a truthful/correct answer -- it makes it less likely you'll contest the ticket, and if you do, they can tell the judge, "when I asked why they thought I'd pulled them over, they told me it was because they were speeding". If you admit to the infraction, you don't really have much of a leg to stand on in court.

[logfromblammo]

And the de jure standard answer is "because you had a reasonable suspicion I was committing a crime," or "I don't answer questions without legal counsel present."

Of course, since many cops will retaliate against smartasses, the de facto standard answer is "I don't know. Why did you pull me over?" This is always truthful, correct, and non-incriminating, because you can't be expected to read the cop's mind.

[kelnos]

Yep, totally. I usually use the wording "I'm not sure", or, better, "I can't be sure", since "I don't know" is often not entirely truthful.