I recently read the book Traffic: Why We Drive the Way We Do (and What It Says About Us) by Tom Vanderbilt, a fascinating look at many aspects of car culture: how roads affect traffic patterns, how both safety and danger are often an illusions, how driving behavior varies around the world, and how traffic deaths are correlated not to GDP or highway spending, but to governmental corruption. This book examines a lot of psychological science and the intersection (hah) between psychology and engineering that goes into traffic management.

It turns out that traffic engineering is not rocket science. It's way more complicated than that.

For example, road capacity is directly related to the demand for road capacity. In other words, if traffic engineers put in a new lane or road to ease congestion on an existing road, they will be confounded by a number of new drivers on that road. Adding to capacity somehow adds to the number of drivers using it (and vice versa: when roads or lanes are removed, for instance by construction, demand falls). This peculiar phenomenon stems from the fact that drivers are independent beings who make choices based on what is available to them. If a road is too crowded, some will choose to make fewer trips (perhaps telecommuting or combining errands into one trip). If new capacity becomes available, some will choose to make more trips (perhaps not making the effort of combining errands into a single trip).

I have some questions for you, dear reader, and would love it if you shared your thoughts in the comments below.

1. What are your traffic pet peeves? What driver behaviors and road conditions drive (hah) you crazy?
2. Do you think you are an average driver, in terms of skill and safety? Below or above average? Why?
3. What do you think of the use of the horn? Is it always rude? When is it not rude?
4. And where do you do most of your driving? I'm wondering about geography, since traffic culture varies widely among locations. New York drivers are very different from London drivers or Salt Lake City drivers.