Friday, December 5, 2008

New Zealand traffic rules

Traffic rules are designed to avoid coordination failures. In much of the world, driving is on the right. New Zealand is one of the island nations in which driving is on the left, the next most popular choice. Uniquely, they have a rule that says drivers taking left turns (which, remember is the turn that doesn't cross traffic) must yield to drivers taking right turns. (Here's a site with a picture. If we had this rule in the U.S. it would mean drivers taking a right must yield to those taking a left.) Apparently this is an inferior coordination rule. On the one hand, a driver planning to take a right turn (across traffic) might appear to be planning not to turn. On the other, a driver planning a right turn who has precedence over a driver taking a left must still yield to a driver going straight, and so errors in signaling in either direction are a problem. So from time to time New Zealanders debate changing the rule: Quirky intersection rule set to face review - again

"AA motoring affairs manager Mike Noon said New Zealand's version was "most probably the most confusing and poorly understood rule that we have".
Although it was designed to reduce the risk of rear-end collisions for vehicles waiting to turn right, he believed that was outweighed by the hazards of side or head-on crashes.
One major hazard was when a vehicle swung right into the path of an opposing driver who might have inadvertently signalled a left-hand turn, but was continuing straight ahead."

Of course, switching from one equilibrium to another (even if superior) presents coordination problems of its own. Maybe September 3 should be Coordination Day, in memory of the day in 1967 when Sweden switched from driving on the left to driving on the right.

2 comments:

EconoMan said...

We used to have the same rule in Victoria, Australia about 12 years ago, at least for a car turning across the same road the other car is on (the left picture not the right one).

It was changed, I believe, to conform with most other cases where turning left had right of way, and because of the risk of someone going straight on despite having the indicator on.

However, it was believed that the old rule (the NZ rule) helps clear the intersection better. 1 car waiting to turn right into a T can hold up a string of cars trying to turn right out of the bottom part of the T. Allowing them to go ahead of a left turner means the string of cars can go while other cars are turning left into their road.

Myrtone said...

An inferior "coordination" rule? Not really, the arguments given by the NZAA have been put into question by a Wellington blogger and podcaster.

One is mentioned in the article:

On the one hand, a driver planning to take a right turn (across traffic) might appear to be planning not to turn. On the other, a driver planning a right turn who has precedence over a driver taking a left must still yield to a driver going straight, and so errors in signaling in either direction are a problem.

Who in all honesty can read this as a valid argument? In New Zealand many drivers do not use their indicators correctly and let's face it, apparently they are lousy drivers. 20% do not observe this specific rule and many more do not stop for amber lights or indicate before they turn.

To understand why this is consider New Zealand's driving laws.

One can get ones learners permit at only 15 years of age and after only six months of learning to drive can drive solo and can get a full license once reaching 17.

Some links regarding the right/left turn rule:

*No right turn - busting the fallacies of NZ's rule.
*Right of reply on right of way - blow by blow debunking of the AA's version of it from the sitting duck blog.
*Sitting duck podcast episode 158 driving social flip flops followed by episode 159 driving me crazy, the latter has a whole section on the rule in question.