On a bus trip in Tokyo, I was surprised to occasionally glance down and see, in a neighboring car, a television screen playing where the nav device might normally sit. Apparently this is a favorite of taxi drivers in a number of other Asian capitals.

The distraction effects of a front-mounted television are obvious. But what about the televisions in the back seats of other vehicles? We’ve all seen it: The ghostly blue flickering of Shrek or some such in the back of an SUV (apparently, children are no longer able to amuse themselves with books, license-plate bingo, or looking out the window). Do they pose a risk for the general traffic stream?

According to a paper by Julie Hatfield and Timothy Chamberlain of the NSW Injury Risk Management Research Centre in Australia, “The impact of in-car displays on drivers in neighbouring cars: Survey and driving simulator experiment,” published in Transportation Research Part F: Traffic Psychology and Behaviour, there is reason to think those displays do effect the behavior of other drivers. Using a driving simulator (this is one of those experiments that would be almost impossible to carry out in actual traffic) with a nearby laptop to simulate in-car displays, the researchers had subjects carry out a number of drives in which they were instructed both to look for the displays, and to ignore them, and drives in which no instructions at all were given (curiously, the effects were similar in this case to when drivers were told to look for the screens). A number of differences were observed in drives in which the displays were present versus when they were not, including a more variable lane position and a slower response time to pedestrians.

What the study seems to suggest is that we can’t but help pay a bit of attention to those moving images in other vehicles. This may depend, of course, on the traffic conditions in the moment; i.e., if we were busy attending to many other stimuli in the environment we would likely screen out non-essential things. But there is that notion too that there’s something inherently seductive in the moving image (as the hypnotized children in the back row will attest to), and that may engage us, almost against our will. The researchers note that their use of a laptop screen does not purely replicate the small screens seen at a distance in the back of cars; but then again, those may cause even more trouble. As they write: “Once attention has been attracted, the smaller screens may produce greater impairment because of the greater cognitive capacity required to make out the materials being screened. Thus, if anything, our results may underestimate the impairment produced by attending to the smaller audiovisual display units that are currently available in vehicles.”

In-car backseat screens are an example of how technology is added to cars for reasons of marketing without really knowing how it will change the driving environment — and, as I mentioned earlier, it is vastly challenging to test such things. I am not suggesting that these have caused a raft of crashes or anything, but given the inaccuracies of crash reporting and the complex interplay of variables present in traffic, it’s actually fairly hard to tell what the effect of the screens is. Perhaps the overall calming effect they have on the passengers in the vehicles in which they are present — and thus the reduction of distraction on those drivers — is more beneficial than the distraction effects they pose to other drivers. In essence, though, they seem to fall into one of those regulatory black holes, in which they are permitted because there’s no evidence they are causing harm, even if that evidence would be incredibly difficult to acquire.

This entry was posted on Wednesday, May 13th, 2009 at 8:25 am and is filed under Drivers, Traffic safety, Uncategorized. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.