Saturday, April 02, 2011


Traffic provides an interesting synthesis of a wide variety of research on "traffic". There are a number of great insights in the book. The key takeaway, however, is that "traffic" is a "social activity", though it is often treated as an engineering problem. If automobiles are made more safe, people will probably just use the safety to kill others instead of themselves. If traffic is made to move faster, people will often use the speed premium to drive further. (People could never have commuted 200 miles a day on foot. However, with cars, some people now do it.)

Traffic problems also date back to ancient times, with Rome suffering from traffic chariot congestion a few millennia ago. (They eventually outlawed daytime traffic, making it difficult for Romans to sleep at night - due to all the nighttime traffic.) One of the issues with traffic today, especially in America, is that it focuses almost exclusively on automobile traffic (with pedestrians viewed as "impediments"). This focus leads to most trips being taken in automobile, which ends up leading to congestion and slower travel times. Even in places like Manhattan where the overwhelming majority of trips are on foot, the majority of the traffic space and resources are devoted to automobiles - with even the signals timed to benefit cars instead of pedestrians.

There is also an interesting comparison of traffic fatalities across nations. Wealthier, more established nations tend to have lower fatality rates. However, this tends to be more a result of the nations being less corrupt. A more corrupt wealthy nation will tend to have a much higher rate than a less corrupt one. Perhaps it is the decrease in corruption associated with wealth that really leads to the lower fatality rate.

The traffic culture also causes some interesting behavior. Drivers in the US will often speed down a road, but stop at a red light - even if no cars are anywhere in sight. Both activities are illegal, but when is considered acceptable, while the other is not. Perception also plays in to the peculiar sentiments and activities. People perceive SUVs as being safer. Yet, SUVs are statistically more dangerous. Is it the personal control that causes this? And while people are willing to take away personal liberties to fight the minor threat of terrorism, they are not willing to do so to fight the much larger threat of automobile crashes.

The author also does a good job of picking apart statistics and our view of them. There are plenty of well sighted studies that come to conclusions after aggregating accident data. However, looking at the data from a different perspective can produce the opposite results. For example, safety data seems to say that a wide road with large buffer zone between the road and buildings is safer. Yet analysis of individual roads shows the narrower sections with buildings nearer to the road have fewer crashes - even though both carry similar traffic volumes. It seems that people often consume the added safety. Perhaps the Dutch idea of integrating roads with human space and stripping away signs really is the way to go.

This book is one of the most objective views of the "traffic" issue. It picks apart at much of the "received" wisdom, yet doesn't attempt to force a specific solution on it. After all, most people would love for everyone else to take transit. They want their street to be a quiet tree-lined road, while the free-flowing super expressway sits just out of earshot.

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