Not a moment too soon we are getting rid of the give-way rule that requires left-indicating traffic to yield to cars turning right across their bows.

It didn't make sense when we followed the Victorians in adopting it in 1977 and it made even less sense when we failed to follow the Victorians in ditching it in 1993.

The right-hand rule that prevailed before 1977 was simple: give way to all traffic on your right and, if turning right, give way to all traffic.

The law now in force requires the yielding driver to assess whether following traffic will deny the right-turner the chance to exercise the right of way.

It throws drivers into a game of white-knuckle risk assessment and mind-reading. An ambiguous rule is a bad rule. For that reason alone it should be changed.

The only thing that doesn't make sense now is why we are waiting until 2012 to introduce the change. Transport Minister Steven Joyce says a long public education campaign will be required.

But it should not take more than a few weeks to devise it and a few months to carry it out.

It is better that we accomplish the long-overdue change before the influx of Rugby World Cup visitors a year from now - not least because any of them who decide to rent a car will be very confused by a rule that is in force in not one other country in the world.