Was pulled over a lot before I straightened my life out. This is super close to what worked best for me.

First, I wouldn't Always say the same thing, it would depend on the feel of the situation, but I'd typically say

"I must have really messed up if you had to pull me over Officer/Sir/Ma'am."

They usually follow that with a "Welllllll."

Most of the time they'd just run my plates and license and let me go. I never meant malice with what I did, I was just stupid. There were definitely times where I didn't do anything to get pulled over. One of those times I got a bogus ticket and that cop was a huge asshole (no, not me being whiny, he was a bully and it was pretty messed up. I was as polite and submissive as possible until he let me go. I contested that one in court). But, if I messed up and was caught and ticketed, I didn't try to weasel out of it, and the Honorable James P Madden came to know me and understand that I was never in his courtroom twice for the same reason and I didn't waste his time, so he often made the penalty lighter. That largely led to me cleaning up my act.