Modules and Wholes

I wrote recently of my feeling, based on personal experience, that roundabouts were cognitively complex. Since writing those views, I discovered the distinguished Canadian human factors engineer Kim Vincente describe roundabouts as "complex and demand attention and mental agility." Clearly, roundabouts, as a technology, are not user-friendly.

Yet Vincente also notes that a particularly complex roundabout, called the "Magic Roundabout" in Swindon England, does not have a particularly high accident rate, despite its complexity. Are roundabouts intrinsically safe despite their complexity, or does something else account for the the safe record of the Magic Roundabout?

At the moment I happen to be reading a book by social anthropologist Kate Fox called Watching the English: the hidden rules of English behaviour. Fox argues that English drivers may be more polite when compared with drivers in other countries. "English drivers are quite rightly renowned for their orderly, sensible courteous conduct....You don't have to wait long until someone lets you out of a sideroad...all drivers keep a respectful distance....people are remarkably considerate about pulling in to let each other pass".... etc.

So perhaps roundabouts can work only in England, land of the gentle driver.

But as a pointed out earlier, roundabouts can result in knots of traffic, where everyone is waiting to give way to the person on their right. This leads to impatience and confusion. Fox doesn't address roundabouts, but she talks at length about queues. Fox argues the English, unlike many cultures, is a "fair play" culture, rather than an opportunistic one. She observes English people having near arguments over who is supposed to go first, each side insisting the other goes first. In an opportunistic culture, people might jockey for position to get their chance to go next.

I am not always convenced by Fox's sweeping generalizations, even though they contain many insights. But I do believe cultural norms of turn-taking affect the success of any system that relies on interpretation to decide how people behave in cars. Unfortunately, when a system relies on cultural norms (instead of unambiguous rules), it can get messy. It is often not clear whose turn it is. When two people arrive at the same place at near the same time, they both have to have seen the same event (one may be daydreaming), and have interpreted it in the same way. If the two people not only have different understanding of what happened, but different expectations about who should go next, it doubles the problem. The use of roundabouts relies heavily on user interpretation, which is why is it problematic. Roundabouts offer two problems: potential differences about who should give way to whom (based on estimations of position and driving speed), and differences in who has the "right" to more next once both parties realize the ambiguity of the situation.