We all know the guy. You are stuck in a slowdown usually for no reason other than rubber necking. Sometimes traffic just slows for no apparent reason at all. Maybe there was a sign encouraging people to merge right or left. You want to be doing 113 km/h but you are stuck at 32 km/h. To make the situation more frustrating you catch a glimpse in your mirrors of car speeding past all the nearly parked cars in hopes that it can merge in ahead of some poor sap. You curse, "why can’t he just get in line like the rest of us!" Then you decide to do your part for society. You will bring justice by moving your car so close to the car in front of you that he can’t possibly merge between you two. If only all the other cars would do the same! We could leave this self-important jackass parked while a solid line of cars cheerfully passes leaving him further behind than ahead. Of course, that never really happens. Some weak person 4 cars ahead of you lets him in. Where’s the vindication?!
William Beaty helped me realize that I am the problem, not the other guy. In his essay, Traffic "Experiments" and a Cure for Waves & Jams he suggests a simple cure to the merging-lane traffic jam I just described. Let them in! I have started doing this and even if 3 cars (or more) merge in front of me it has little to no impact on my arrival time at my destination. It does feel good to have not fought someone (positive karma). I have put my family at less risk by not tailgating another driver or inciting road rage in the merging driver.
Drive by looking down the road. We should be doing that anyway. When you see a slowdown, not when you start experiencing it (although it is never too late), create a gap in traffic between you and the car in front of you. If a car merges into that gap, recreate the gap. It works! It feels good! Traffic moves better. And you have been a safer driver.
Update 7/24/2014: And 7 years later, this hits the news: http://arstechnica.com/cars/2014/07/the-beauty-of-zipper-merging-or-why-you-should-drive-ruder/