Sunday, November 15, 2009
Traffic notes, part 2
Earlier we posted some quotes from the book Traffic: Why we drive the way we do (and what it says about us). It's an excellent book with many insights into what happens when people get behind the wheel. Here are a few more quotes from the book:Car companies would rightly be castigated if they advertised the joys of drinking and driving. But as a survey of North American car commercials by a group of Canadian researchers showed, it is quite acceptable to show cars being driven, soberly, in ways that a panel of viewers labeled "hazardours." Nearly half of the more than two hundred ads screened (always carrying careful, if duplicitous, disclaimers) were considered by the majority of the panel to contain an "unsafe driving sequence," usually marked by high speeds. pp. 66, 67
"Baker's law," named after crash reconstructionist J. Stannard Baker, notes that drivers "tend to explain their traffic accidents by reporting circumstances of lowest culpability with credibility" —that is, the most believable story they can get away with. p. 72
"If you're limited in how many things you can pay attention to, and attention is a gateway to consciousness, then you can only be aware of a limited subset of what's out there." Inattention blindness, it has been suggested, is behind an entire category of crashes in traffic, those known as "looked but did not see accidents." p. 83
This attention disorder could also help explain the "safety in numbers" phenomenon of traffic, as described by Peter Lyndon Jacobsen, a public-health consultant in California. You might think that as there are more pedestrians or cyclists on a street, the more chances there are for them to be hit. You are right. More pedestrians are killed by cars in New York, City than anywhere else in the United States. But as Jacobsen found, these relationships are not linear. In other words, as the number of pedestrians or cyclists increases, the fatality rates per capita begin to drop.
It is the behavior of drivers that changes. They are suddenly seeing pedestrians everywhere. The more they see, typically, the slower they drive; and, in a neatly perpetuating cycle, the more slowly they drive, the more pedestrians they effectually see because those pedestrians stay within sight for a longer period. p. 85
Dutch cyclists are safer simply because there are more of them, and thus Dutch drivers are more used to seeing them. ...Gainesville, a college town with the highest cycling rate in the state, is in fact the safest place to be a cyclist. p. 86
Studies have shown that drivers seated at higher eye heights but not shown a speedometer will drive faster than those at lower heights. p. 94
We "overdrive" our headlights, moving at speeds that would not allow us to stop in time for something we saw in the range of our lights. p. 98
Studies have shown that pedestrians think drivers can see them up to twice as far away as drivers actually do. According to one expert, if we were to drive at night in a way that ensured we could see every potential hazard in time to stop-what is legally called the "assured clear distance"-we would have to drive 20 miles per hour. p. 99
The "slower is faster" idea shows up often in traffic. The classic example concerns roundabouts. Many people are under the mistaken impression that roundabouts cause congestion. But a properly designed roundabout can reduce delays by up to 65 percent over an intersection with traffic signals or stop signs. p. 124
One of the curious laws of traffic is that most people, the world over, spend roughly the same amount of time each day getting to where they need to go. Whether the setting is an African village or an American city, the daily round-trip commute clocks in at about 1.1 hours. p. 131
"Baker's law," named after crash reconstructionist J. Stannard Baker, notes that drivers "tend to explain their traffic accidents by reporting circumstances of lowest culpability with credibility" —that is, the most believable story they can get away with. p. 72
"If you're limited in how many things you can pay attention to, and attention is a gateway to consciousness, then you can only be aware of a limited subset of what's out there." Inattention blindness, it has been suggested, is behind an entire category of crashes in traffic, those known as "looked but did not see accidents." p. 83
This attention disorder could also help explain the "safety in numbers" phenomenon of traffic, as described by Peter Lyndon Jacobsen, a public-health consultant in California. You might think that as there are more pedestrians or cyclists on a street, the more chances there are for them to be hit. You are right. More pedestrians are killed by cars in New York, City than anywhere else in the United States. But as Jacobsen found, these relationships are not linear. In other words, as the number of pedestrians or cyclists increases, the fatality rates per capita begin to drop.
It is the behavior of drivers that changes. They are suddenly seeing pedestrians everywhere. The more they see, typically, the slower they drive; and, in a neatly perpetuating cycle, the more slowly they drive, the more pedestrians they effectually see because those pedestrians stay within sight for a longer period. p. 85
Dutch cyclists are safer simply because there are more of them, and thus Dutch drivers are more used to seeing them. ...Gainesville, a college town with the highest cycling rate in the state, is in fact the safest place to be a cyclist. p. 86
Studies have shown that drivers seated at higher eye heights but not shown a speedometer will drive faster than those at lower heights. p. 94
We "overdrive" our headlights, moving at speeds that would not allow us to stop in time for something we saw in the range of our lights. p. 98
Studies have shown that pedestrians think drivers can see them up to twice as far away as drivers actually do. According to one expert, if we were to drive at night in a way that ensured we could see every potential hazard in time to stop-what is legally called the "assured clear distance"-we would have to drive 20 miles per hour. p. 99
The "slower is faster" idea shows up often in traffic. The classic example concerns roundabouts. Many people are under the mistaken impression that roundabouts cause congestion. But a properly designed roundabout can reduce delays by up to 65 percent over an intersection with traffic signals or stop signs. p. 124
One of the curious laws of traffic is that most people, the world over, spend roughly the same amount of time each day getting to where they need to go. Whether the setting is an African village or an American city, the daily round-trip commute clocks in at about 1.1 hours. p. 131
Labels: tom vanderbilt, traffic
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