Raising speed limits doesn’t lead to faster driving

I’ve seen several articles about this lately as several states consider raising highway speed limits: raising the speed limits does not lead more people to drive faster.

Traffic experts say that motorists tend to drive at a speed they feel comfortable, regardless of the posted speed limit. And according to Michigan Department of Transportation spokesman Rob Morosi, comfortable drivers generally make for safe roads.

“There’s a misconception that the faster the speed limit, the more dangerous the road,” said Morosi, “and that’s not necessarily true. Speed limits are most effective when the majority of people driving are comfortable at that speed.”…

Common sense, then, would suggest that increasing a speed limit would lead those motorists to increase their speed at a similar rate. But Megge, pointing to I-96 in Flint as a striking example, says that belief is not supported by the research.

Before 2005, traffic studies indicated that most motorists were traveling the Interstate at roughly 73 mph, he said. After the speed limit was increased, most motorists still traveled the Interstate at roughly 73 mph.

“When we raise a speed limit, traffic speed does not automatically increase. That’s a myth,” Megge said. “I’ve been doing this 15 years and raised 300 speed limits, and never have we seen or observed a wholesale increase in traffic speeds. It’s a very counter-intuitive idea. But the science and engineering works. We want to ensure it’s safe and fair to the public.”

Common sense approaches often don’t apply to traffic. This finding about speed limits fits with another finding about traffic signs: drivers don’t necessarily pay attention. Read about several places in Europe that have no traffic signs and few traffic markers and safety improves. In the case of driving speed, drivers seem to pay more attention to nearby drivers rather than the official speed limit. So even as people often drive solo and might argue their actions on the road are the result of their own individual choices, driving is indeed a social activity.

Here is a second good example regarding traffic that counters “common sense” or common behavior: using all possible lane space to merge is more efficient for everyone rather than having drivers block off lanes that will soon close.


Sociology: challenging common sense

One simple way to view sociology is that it often challenges common sense understandings of the world:

We talk a lot about common sense; as if that’s a good thing. I remember my uncle describing a guy once by saying that he was smart as a whip but didn’t have a lick of common sense. So it has always been something held up as a good thing. The problem is that common sense is sometimes wrong too. In my sociology classes each semester, we take ten common sense statements and prove their error through research, rather than just assuming they’re correct because they sound right.

A few quick thoughts about common sense.

1. Common sense is often cultural. In other words, different cultures have different default or common understanding about how the world works.

2. Common sense is often learned through socialization. Sometimes this happens explicitly, such as when parents talk to a child, but other times it happens through observation. Kids have to learn about common sense and has to know how society “typically” works.

3. Sociology courses are a good place to discuss common sense because we tend to talk about topics that people haven’t thought through before. Why do people live where they do? Why do some occupations get paid more than others? What is behind going to college? Why do we attach certain ideas or statuses to particular objects, like a house or an Apple laptop? Sociology often “pulls the curtain back” on social life, exposing what is really influencing our actions and group behavior.

4. This is not to say common sense is necessarily wrong. But the issue is that many people do not have the time or take the effort to evaluate common sense. College is a good place to learn how to evaluable common sense through critical thinking, reading, and writing.

5. Challenging common sense is not an easy task. We like our typical explanations for how things work. Even when confronted with better evidence, we tend to stick with our accepted ways of thinking. You see this all the time in the political realm: the ideological commitments of each side can trump evaluating the facts.

6. Common sense is a typical foil for much academic work. Here is a typical academic argument: “the accepted wisdom is X but we have research that shows it actually is more like Y.” Or, “there is a typical explanation for this phenomena but we think the real world is more complex or is more nuanced.”

Sociology: helping us move beyond common sense (and individualistic) understandings of the world

This overview of the recent book Everything is Obvious Once You Know the Answer: How Common Sense Fails Us does a decent job in explaining why sociology helps us move beyond common sense understandings of the world:

This thought-provoking book challenges the universal belief that management decisions based on common sense – rooted in best practices, hunches and experiences – often lead to the best outcomes.  According to the book, the reality ends up being quite different.  Relying too much on common sense often leads well-intentioned and intelligent people to make poor strategic and tactical decisions in areas such as capital investments, product introductions, new market entry and advertising decisions.

Watt’s supposition is that people give too much credence to their prior and accumulated experiences, history in general and what they perceive as best practices when making decisions.  According to the research, a person’s common sense is faulty for a number of reasons:  it contains intrinsic bias; it is based on unproven or wrong assumptions and; it is too difficult to deduce clear-cut conclusions and action steps from an environment that is overly complex or unclear…

Relying on common sense for decisions or to make predictions has dangerous implications.  For one thing, reality is usually very different from what was first imagined.  The future is quite complex and rarely reflects the same conditions that earlier decisions were based on.  As a result, it is highly unlikely positive outcomes will repeat themselves if the individual relies solely on history.  In my consulting experience,  the higher degree of uncertainty around a decision or potential outcome, the more likely senior executives will rely on subjective criteria like common sense or best practices as a basis for decision making.

I’ve made a similar argument to students: we tend to operate on a day-to-day basis by seeing things in terms of how we have seen or experienced them before. We make patterns out of things (we are pattern-making creatures) that have happened to us regardless of the amount of information to back up our conclusions. New information is then filtered through these older constructs. When confronted with new information that doesn’t “fit,” we have to ignore it, fit it into our old constructs, or develop new constructs.

Thinking sociologically means that we move beyond this individualistic level in a couple of ways:

1. We try to take a broad overview, recognizing that the world is complicated and many things are related. Instead of just thinking about how something affects us, we look at how systems are connected and social processes take place. The question is more “how does the whole affect the individual” rather than “how does the individual fit within the whole.”

2. Conclusions should be based on data that is collected and analyzed in ways that minimize individual level bias. Though we often are unable to create perfect models or understanding, we can make good estimates.

I may have to try out this description with my students to see what they think.

Venkatesh discusses five myths about prostitution

Sociologist Sudhir Venkatesh quickly dissects five myths regarding prostitution. Here are the myths: “prostitution is an alleyway business,” “men visit sex workers for sex,” “most prostitutes are addicted to drugs or were abused as children,” “prostitutes and police are enemies,” and “closing Craigslist’s “adult services” section will significantly affect the sex trade.”

Two quick thoughts:

1. It is difficult to tackle a social problem if people don’t know what is really going on. If Venkatesh is right about the role of Craigslist, then lawmakers and officials are just dealing with symptoms of the problem.

2. One common argument against the need to study sociology is that everything about the social world is “just common sense.” Venkatesh is suggesting based on research of his own and from others that much of the accepted wisdom about prostitution is inaccurate.