What It DEW?

Slow traffic is bad in every possible way. It wastes time and gas. It spews harmful emissions. It hinders emergency vehicles. It sucks.

What should be done about it? Pretty much everything that can be done, from the vapid (building more lanes) to the lucent (see below). Guess which route my moronic state favors.

Building more lanes will help, but it requires seizing land and destroying vegetation. As well, it does nothing to reduce the number of cars on the road, so, beyond slightly boosting commuters' fuel efficiency, this solution isn't "green." In Austin, we have much more highway than we need for about 18 hours per day. (Middle lanes of varying-flow-direction-by-time-of-day strike me as profoundly more useful than empty spaces between medians.)

Mass transit will help. It should be pursued with utmost fervor. However, it costs money and angers morons.

Staggering work hours, telecommuting, and any other clever workplace arrangements that can be made to alleviate traffic are applaudable. Our government should provide tax incentives to businesses to encourage them. I'd also love to see a break for those of us who live within ten miles of the workplace.

These solutions are all evident to even the dullest of road users. Their underuse is our shame. But these solutions are but David Spades compared to the Will Ferrell of Driver-Engendered Wavebreaking (DEW). DEW is a completely accessible driving technique that can potentially alleviate highway rush-hour traffic without removing any cars from the road. How much alleviation is uncertain, and it doubtlessly increases with the portion of drivers who perform DEW, but I estimate that its widespread use could keep the thickest of highway rush-hour traffic rolling along at 30 miles per hour.

Brakelights propagate in backwards-moving waves along crowded highways. This is because of the rule that rush-hour drivers follow: go as fast as you can without hitting the person in front of you. This means that when the person in front of you (who isn't going as fast as you'd like) brakes, you then have to brake, too. Of course, the only reason the person in front is braking, as though his already-snail's pace was too fast, is that the person in front of him braked. And of course, your braking makes the person behind you brake, and so on. The result is the familiar stop-and-go motion of the urban highway at rush hour.

It is reasonable to ask why, and where, the wave starts. The frustrated commuter imagines some lollygagger about five miles up, trundling along, oblivious to the anguish and environmental damage he's causing behind him, possibly saying hello to his equally-idle friend in the neighboring lane, which explains why that lane isn't going anywhere either. This is silly - we often get near the edge of town, and traffic starts picking up speed, without any apparent obstruction. The true reason for the wave is that, like a drop in a pond, all it takes is a tiny tap of the brakes to send a ripple propagating for miles. There are any number of reasons to tap the brakes - rounding a sharp turn, entering a Pittsburgh tunnel (A.K. once told me), passing an accident scene (whose brake waves are often misinterpreted as the result of rubbernecking), or, importantly, letting onto the freeway entering traffic. I interpret the particularly slow Austin traffic in areas with closely spaced on-ramps as waves originating from this last kind of brake tap. Another way of putting that is that too many cars are trying to get onto the freeway at once, and excessive slowing down to accommodate them turns into complete stopping because of the backward-propagating waves.

DEW is accomplished by supplanting the one primary rush-hour driving rule with another: leave adequate space for a vehicle to pull between you and the next vehicle up, at all times. Doing this accomplishes two things: it gives merging traffic more spaces to smoothly enter the freeway, and it helps the driver to break backwards-propagating brake waves (you will have to brake later, or perhaps not at all, with extra spacing between you and the next car up). DEW has the added benefit of safety, but the dangers of rear-ending someone at rush-hour speeds are minimal.

The effectiveness of DEW has not been measured, although with some organization it could easily be. Timing the trip along IH-35 from the Yager exit to the Onion Creek exit (through Austin, going north to south), beginning at 4:30 pm, every business day for two weeks, then getting 50 cars to enter at Yager between 4:25 and 4:35, and practice DEW all the way down, and timing their trips over the following two weeks, would, I think, provide an effective test. The primary goal would be to have the overall trip time lowered using DEW, and I believe that would happen, although the wavebreaking effect would compete with the effect of the lower maximum speed an individual DEW car attains (compared to a nearby non-DEW car, which accelerates more, briefly, to close the gap in front of it faster, in accordance with the non-DEW driving rule). I am compelled to disclose that I take an immense personal satisfaction practicing DEW in the rare occasion that I am in rush-hour traffic, regardless of the fact that I am passed so often that I usually end up ten or so cars back from where I would be, had I not done the DEW. Nevertheless, even if the overall velocity is not increased, the fuel efficiency lift and lack of wear-and-tear associated with less braking would still make DEW worthwhile.

The beauty of DEW is that one person doing it helps. 50 people doing it within ten minutes of each other would likely help even more, but DEW is not something that has to sit under review by a government of dunces, or be built using taxpayer dollars. It is free to anyone who wishes to dabble in it. The cost is being passed by a few cars; the rewards are breaking a wave, possibly increasing everyone's overall speed, and, if you're like me, smug satisfaction that you're doing the right thing and helping everybody out with your superior style.