If all lanes are packed, slowly increase the distance to the car in front of you. This so you don't have to slam your brakes should that sudden sea of brake lights appear. You can brake slower and avoid getting rear ended by the tailgater.

The A4 is the perfect car for annoying tailgaters. Use the rear fog lamp, Luke. Its force at night is tremondous.

BTW, I was driving w/ a friend in the #2 seat during rush hour. I had a few tailgaters smelling my exhaust and I was going into an uncertain situation. I covered my brakes for safety, as instructed in defensive driving. They saw the brake lights and panicked. I triggered a multi-car fender/bumper bender.

Too bad.....I feel no remorse because I was doing the speed limit, in the right lane and was overtaking traffic in the center(left) lane that was stopped. This isn't the first time I've seen a pile-up there. Its right in front of a firestation so there is little need for me to stop.

BTW, there was a tailgater this afternoon who stopped behind me ON THE FREAKIN RAILROAD TRACKS!
His dually crew-cab F350 4X4 would have been great locomotive bait. Just proves some of Darwin's theories were correct.

Pull on your hand brake, hard. This will make you slow down fast with no brake lights. However, be prepared to accelerate rapidly should the person behind you get to close.

disclaimer: The above does not mean I've used this method nor does it mean I endorse, sanction or condone it.

move over and get out of the SOB's way... if it happens to be a commerical vehicle, get the number of the truck, the tag number, and the name of the company (often comes with a phone number on the side of the truck)... get on your cell phone, call the company, POLITELY ask to speak to the safety officer or company manager and explain what the offending driver is doing. This often gets great results...(can you say pink slip?) Bait aggressive drivers into a confrontation, especially if they are in big trucks, and you will lose. Call their boss, honest, it works!

I hate to say it, but this sounds to me like a really risky move. If the tailgater is following too close to stop safely, braking without taillights is a great way to ensure that it'll happen! Sure, if he/she hits your bumper (or worse), you can say, "I told you so," but what's that worth if the price is damage to your car and possibly yourself and your passengers?

slow down, but not by using the hand-brake as someone suggested. Slowing down will almost force their ego to effect a pass, getting them off your ass. In the case of big trucks, slow down gradually (those rigs don't stop on a dime, you know), they have to run through the gears (and some have 15 or more speeds with multiple boxes), they HATE that. To speed back up from say, 45 m.p.h., in the center-right lane, to 65 or 70, the driver must row back up through all those gears again. Did I mention that they HATE that? They don't want to run onto your bumper any more than you want them to - they risk losing their insurability, license, and livelyhood. They'ld REALLY hate THAT. Expect a single-digit salute of appreciation - it'll just warm your heart to know you've made his day.

Tailgater almost always slows down. They usually get the idea after a few good squirts. Next step: rear fog light. But I use these weapons ONLY in self-defense after moving away from the offender if possible.