Signs When Driving

I was driving home from work on I-95 which was traffic about two car lengths apart going around 70mph. I was thinking about semiotics and my turn signal.

It’s a good example because the most surface interpretation of a turn signal is a blinking light. When I stick it on a car, and particularly on a certain side of the car it has additional levels of meaning from that context.

Why do I signal?

  • It’s habit? I sometimes signal when I’m on a road by myself. I am conditioned to catch the turn signal with my hand as I turn the wheel.
  • It’s the rule? I’m more likely to signal if there’s a cop driving behind me.
  • It’s polite? I sometimes wave to drivers that let me into traffic and there’s an abstract sense of a social dynamic between me and the rest of the cars. If someone cuts me there is a sense of a breach of social contract. It can even change the dynamic and I’ll start driving more aggressively — treating the whole of traffic as an organism to be responded to.

Motivationally there are lots of ways people explain their behavior. Arguably, however, the practice began because it is important for me to inform other drivers of my intentions. The social structures of politeness and law were created to support this. (And over time I grew conditioned.)

Why is it important for me to inform other drivers of my intentions? Well, clearly so that they can plan their actions accordingly. Either they can slow down and let me over or change lanes or whatever.

Driving is a pretty simple example of planning. Everyone has pretty straightforward goals: get where you want to go with a minimum of waiting and death. To do this we are constantly guessing as to the future behavior of other drivers. Most of the communicative signs are in the form of various lights, though there are things like the size and color of the vehicle.

If I see a red Masarati I expect it to be more likely to be going fast than an old Pinto. (One of the strange groups of people I expect to be going fast are minivans. Though I’ve driven a minivan and had to remind myself I’m not a dork. (Semiotically, I’ve recognized the minivan as a sign exemplifying the myth of the castrated man so I drive a bit faster as a sign exemplifying the myth of the bad boy.))

Consider this excerpt from Speed, Speed Dispersion, and the Highway Fatality Rate

Two main paradigms have been proposed to explain why some states have a higher fatality rate than others. The “speed kills” paradigm assumes that the likelihood an individual driver will suffer a fatal accident increases with speed. It relies on the physical concept that the damage suffered by a colliding body is proportional to its kinetic energy and, thus, to the square of its speed. An alternative to this traditional approach assumes that it is the variability of speeds among drivers, and not speed itself, that causes highway fatalities. The rationale for this “variance kills” paradigm is equally simple: more speed dispersion results in more passing, thus increasing the probability of a fatal collision. […]

Using data aggregated by type of highway for each state, Lave found the standard deviation of speeds to be positively related to the fatality rate. In contrast, no significant effect of the average speed on fatality was found. He concluded that “variance kills, not speed” and suggested that the focus of speed laws should be changed to that they coordinate speed rather than limit it.

Speeding is a sticky issue. There’s the question of reaction times and that two car lengths at 70mph means that I will hardly have time to register that an accident occurred in front of me before I’d dead. I’ve only come close to an accident once though and it was driving on an interstate going about 70 and changing lanes almost into someone who was approaching me from behind at about 95.

A person is always balancing how long they look back to check that someone is approaching with how long they draw their attention from paying attention to the cars on other sides. The predictive model of other drivers gives us criteria for how far back it is appropriate to examine. When someone is acting significantly outside of that expected model it means that the assumptions are invalidated and, as mentioned above, accidents happen.

This is supported fairly well by this graph from Cirillo’s Interstate System Accident Research – Study II:

Cirillo 1968

It isn’t going fast that causes accidents, it’s going a different speed than everyone else, including going slower.

What does this have to do with semiotics? Well, predicting responses is what we do all day. When I meet someone new I look at their age, their ethnicity, their clothing, their grooming, their language and host of other things and make predictions about their behavior. I alter my behavior given on my concept of that other person (and my concept of myself) to attempt to get desired responses.

These behavioral predictions only make sense within shared cultural narratives — myths. The repercussions aren’t always as immediate and definitive as death or dismemberment, but they are no less real. We are social animals and our jobs, romance, entertainment, safety and emotional health all rely on interactions with other people.

Traffic is just one type of complex social interaction supported by a network of individual agents maintaining complicated predictive models.

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