To me, this always seemed a smug and arrogant way for a person of authority to begin a conversation about a traffic stop.
“Good afternoon sir, I pulled you over because…” seems more appropriate.
Is there some legal purpose to this bizarre line of questioning off the bat? Are they hoping for some profession of sins before the Miranda Rights reading?
They pulled you over because the tail-light is out, and they are hoping for you to say, “Yes, officer, it’s because I have a 100 pounds of illegal drugs in my trunk, right?”.
Because you like getting shot in the face?
Because whatever you say will make it into the little repot on the back of the citation. “Violator stated I pulled him over because he was driving 75 miles per hour”. If it goes to court that little statement will get read when the officer testifies and it does carry weight.
I use a technique called Verbal Judo.
“Good evening. I’m Officer Beitz with the Thistowne police department. I want to see your driver license, vehicle registration and insurance card. The reason I pulled you over is because I clocked your vehicle with Laser traveling 48 miles per hour and the posted limit is 30.”
This answers a lot of questions people start babbling about why they are pulled over and it answers them immedietly. Then I may ask them if they knew what the limit is, if they realized how fast they were traveling, and if they can justify traveling that fast. I can be in and out of a traffic stop with a cite issued in 6 minutes or less.
And since ‘82 I have not lost a single one of my speeding cites.
I was pulled over on a State highway and the officer asked me in an exasperated tone “Why the hell are you driving so slow?” I was explaining to him I drive slow in that area because the log trucks will take you out, because they drive allover the road. He was opening his mouth to, I don’t know, chew me out more when a log truck came around the curve and nearly ran him over. He said " point taken" and waved me on. I always have reasons on this particular road.
The LEO is hoping you will self-incriminate. Doing so gives the LEO even more evidence that you’re guilty.
“Are you usually this forgetful?”
mmm
“Didn’t you see the stop sign?”
“Oh, yes I did, really officer, I was paying attention, and your speed gun should have told you I wasn’t speeding, but I just couldn’t stop in time”
“Well, if those things are all true, you must be driving with faulty brakes and tires. Here’s a citation for those.”
This came up in a driving course I took. You get cited for driving a faulty vehicle. How can a cop possibly have analyzed your vehicle, when the repair shop takes half a day to run diagnostics?
About five people chimed in at once, “Because you told the cop your vehicle is faulty.”
“Aw man, this damn car, officer, I am completely attentive to all road situations, never distracted by the radio, or my cell phone or my mood, I never speed, and yes, I had a beer an hour … uh … 3 hrs ago and I didn’t finish it even. It can’t be me. The car is conspiring against me. All these chips they put in. The CIA must have tapped into them. Conspiracy!”
When we were teenagers, my friends got out of missed stop signs with a “Sorry officer, must have hydroplaned.” Well, maybe that works, if its raining or snowing. Then again …
“Well, your tires look OK. But I have a depth gauge right here … oh, you’re right, they are bald. Here’s your citation. And thank you for your co-operation.”
That never happened, but it could have.
“Sir, your eyes look red have you been drinking?”
“Officer, your eyes look glazed, have you been eating doughnuts?”
We’ve discussed this before, I think the generally accepted ‘correct’ answers are either “I don’t know” or “I’d prefer you to tell me, officer” - delivered politely and respectfully, they might increase your chances of getting away with a warning rather than a ticket.
I think a good answer would be, “Because you like meeting new people?”
Or maybe, “Well, you’re the professional, and if you don’t know, I sure don’t.”
Not so much “more” evidence, but “backup” evidence. If the only evidence is the cop’s word or a radar measurement from a radar gun whose calibration might be questionable, then there’s room for you to fight the charges in court. OTOH, if you openly admit to violating the law, that’s much harder for you to contest in court.
I’m on board with pkbites. I instruct at a police academy and we train our recruits to just tell the driver the reason for the stop at the beginning. You can find verbal judo videos on YouTube and it makes perfect sense. Getting an admission form the driver isn’t as important as you might think. This isn’t the Lindbergh kidnapping that’s being investigated. If that’s what you case depends on, you shouldn’t have made the stop in the first place. IMHO, the real reason most officers do it is because they’ve seen it on TV, had it happen to them before they were cops or had a training officer do it. If you ask them why they ask the question, they usually can’t give a logical answer.
I was pulled over by a CHP officer at around 3am on the 101 going from the Bay Area to Santa Barbara. I was going 75 mph. He asked me how fast I was going and I told the truth. He started laughing and said something like, “you’re the first honest person I’ve pulled over in weeks. I’m going to let you go. Please slow down.”
“Do you know why I pulled you over?”
Best answer: “No, I don’t, Officer. Is there a problem?”
Worst answer: “Because I have a dead hooker in my trunk?”
I have encountered the “Do you know how fast you were going?” question a few times and from experience I have learned to not suggest a speed and simply let him tell me how fast I was going. I used to say “I didn’t think I was going that fast” but I have learned that copping to the crime and apologizing works better and usually gets me a warning. In one situation I admitted I was speeding even before he said anything and apparently my honesty was so unusually he just chuckled and let me go. I’ve seen people argue with the cop, or cry in front of the cop, all to no avail. I’ve found the more angry you get the more likely you will get a ticket, and you may end up getting arrested. You have to give the cop a reason to give you a warning and let you go, and honesty seems to work for me most of the time.
I think it was Drew Carey who said this in a stand-up routine [paraphrased]: 'It’s good to be rich. Now that I’m successful and have a lot of money, I like to go out driving on nasty days when it’s pouring rain and look for cops. Then I run a stop sign. When the cop gets out of his car and into the rain and asks, “Do you know why I pulled you over?” I say, “Do you know why I ran the stop sign?” 
’
I’ve always assumed they were trying to assess the driver, by asking a question without a trivial answer. Right away they get a chance to gauge your demeanor, and the likelihood of a problem.
“Why did you pass in a no passing zone?”
“The cars in front of me (one of which was you) were going too slow.”
She just gave me a warning despite the fact that I was obviously livid with rage,