Archive for January 30th, 2009

Via Mobilizing the Region:

How times have changed. As of today, the national average for a gallon of regular gasoline is $1.85. This may be just a temporary drop, but it’s nevertheless relatively cheap to drive again.

Through the first eleven months of 2008, driving has fallen an astonishing 102 billion miles, a drop of 3.5 percent over the same period in 2007. Assuming that trend holds true through the end of the year, it would represent the biggest decline in driving since World War II.

The Bureau of Transportation Statistics’ new 2009 “Pocket Guide to Transportation” is out and available here (as a pdf or a free hard-copy, that they’ll mail to you, courtesy of your tax dollars!).

It’s chock full of information, much of it rather depressing, like the attached chart, which is titled, “Transportation’s Share of U.S. Petroleum Use: 1975-2007.”

Note how the jump begins right around 1980, when Detroit really began to starting cranking up in earnest on the ‘light truck’ loophole (wiping out all the efficiency gains of the previous decades) the one that helped kill any impetus for innovation in Detroit and thus brings us to our current sorry state of affairs…

Over a lunch I recently attended at the Applied Physics Laboratory at Johns Hopkins, the talk turned briefly to the difficulty of modeling human behavior in large-scale evacuations of people in cars, as occurred during some of the recent hurricanes. “What happens when the driver turns around and sees a big black cloud in the sky?” as one person put it.

Of course, modeling routine traffic behavior presents myriad challenges of its own, which is probably why it is still such a robust activity. As Dirk Helbing notes in his article, “Traffic and related self-driving many-particle systems,” in Reviews of Modern Physics, “Altogether, researchers from engineering, mathematics, operations research, and physics have probably suggested more than 100 different traffic models, which cannot all be covered by this review.” (the article, by the way, is 75 pages long).

Some of these consider traffic flow as a kind of fluid behavior, some have looked at the behavior of “car following,” how one driver is “attracted” and “repulsed” by the person in front of them (which then laid the challenge of how to model a single driver, with no one ahead of him), others have delved into “cellular automata.” Some have tried to break driver behavior down into a complex range of attributes. But as Philip Ball notes in his excellent book Critical Mass, “the more complex the model, the harder it becomes to know what outcomes are in any sense ‘fundamental’ aspects of traffic flow, and which follow from the details of the rules.”

So while large-scale models can with some success predict, say, the formation of traffic jams, there’s an inherent amount of built-in “noise,” e.g., human behavior. For example, I have a bit of an aversion to driving right next to someone. If I’m cruising along at a comfortable speed, but then notice a car in the neighboring lane is unnervingly keeping the same speed, I will accelerate or decelerate, to have my own pocket of space. Are all drivers like this? If not, how many? How do you model something like that? (more…)

The Brooklyn Daily Eagle reports on a radical new traffic calming device potentially coming to my borough:

“It was also suggested that “barn-stands” be put in place at every intersection along Tillary, which would allow simultaneous crossing on all four sides and diagonal crossing from corner to corner — similar to what is permitted at Court and Montague streets in Downtown Brooklyn.”

What a lovely idea! Maybe even a petting zoo or two. There’s nothing nicer than a — wait, what’s a barn-stand? The stands inside a barn? A news-stand shaped liked a barn?

The writer actually misheard, in the style of “Kiss this Guy” and other misunderstood lyrics, a reference to a “Barnes Dance,” not a quaint Amish tradition but named for former NYC traffic commish Henry Barnes (though he invented the concept in Denver), and it refers to an “all-way pedestrian scramble” in which pedestrians briefly have right of way at all intersection crossings.

Still, I wouldn’t mind buying my NYT from a little red barn…