I’ll mention it a third time. Also of note:
-do not do anything to make the officer think his safety might be in jeopardy. The more comfortable he is, the better off you will be.
When stopping, pull as far away from the driving lanes as you can without getting stuck. The officer will appreciate having as much room as you can give him between his ass and the driving lane behind him, and it will demonstrate that you have an awareness of road safety issues. Traffic stops are dangerous for cops not just because of the person being stopped, but because of idiots driving by who slam into them with maddening regularity. Some officers will preemptively remove you from your vehicle - not just to get a closer look at you, but to get both of you away from those kinds of wrecks.
If it’s dark out, turn on your dome light as you stop so he can see clearly into your vehicle. Keep both hands on the steering wheel unless you’re reaching for something the officer has requested.
Before reaching into an out-of-view location for any document the officer has requested, inform him of its location and ask for permission to reach for it. Example: “My license is in my back pocket, do you mind if I reach for it?” “My registration and proof of insurance are in the glovebox, do you mind if I reach for them?” When you reach, try to avoid blocking his view of what your hand is doing. If there is a weapon near where you will be reaching, inform the officer first and then follow his instructions exactly; if he suddenly notices the weapon with your hand next to it, he’s liable to get real excited real fast, and you may get hurt. After you hand him the document, put both hands back on the steering wheel.
If you’re standing outside of your vehicle with the officer, stand still and keep your hands folded in front of you. Don’t wander around, don’t wobble; you raise suspicion about your intent, and at the very least you look like you’re not taking the encounter seriously.
If you didn’t commit the offense he accuses you of, feel free to deny it in a firm-but-polite manner. Vigorous or angry denials won’t get you anywhere, and may put the officer in a bad mood; if the cop is wrong but insists on citing you, you’ll need to sort it out in traffic court. If you intend to go to court, take detailed notes as soon as you can after the traffic stop is over; read as much as you can on the legal concept of “present recollection refreshed.” Having said all that, be prepared not to win in court, particularly if it’s nothing more than his word against yours.
If you did commit the offense, you shouldn’t lie about it during the stop (or in court), but you need not confess to it, either. If the officer is fishing for an admission of guilt - “do you know how fast you were going?” - you can respond with “I really couldn’t say.” If he starts out with “I clocked you at 80 in a 65,” then the nature or extent of your infraction is not up for discussion, and an honest apology is probably your best bet. What he does after that is going to be determined by your driving history (which he will look up once he gets your driver license) and the sum of your behavior during the encounter so far.
I’ve had two traffic stops in the past six years in which I believe these sorts of things got me through without any citation. Both were on my motorcycle, on the highway. When the officer walked up on my right side, the first thing I said was, “do you mind if I dismount so we can both move away from the traffic lanes?” In both cases the officer said yes. I dismounted, walked ten feet down the bank, planted my feet and clasped my hands together in front of me, and stood facing oncoming traffic so I could watch for incoming vehicles:
-first case was 80 in a 65, and that was the officer’s opening line. Not much I could do except apologize. With his permission I reached into my pocket for my license, and into my bike’s glovebox for the registration. He went back to his patrol car and sat in there for a good five minutes dealing with his radio, computer, and pen. I stood in the same spot, still watching upstream for cars that might hit us. When he came back out, he handed me a written warning and sent me on my way.
-second case was for me swerving in front of a vehicle in the passing lane. Asshole was driving there for no reason, and after riding behind him for considerable distance I got frustrated, gunned it, swerved in to the driving lane, passed him, and then swerved back into the passing lane right in front of him. Surprise, there was a motor cop a tenth of a mile behind me who saw it all go down, and he pulled me over. He asked why I did what I did, and I told him the truth: I was frustrated by this guy driving in the left lane, I let it get to me, and it was a stupid thing to do. I handed over license and registration (again, retrieved from their hiding places with his permission), and stayed planted in one spot while he walked back to his bike; after he checked my record, he let me on my way.