The Coroner has recommended all rental vehicles include signs telling the driver which side of the road they should be on.
The recommendation follows the deaths of a German tourist and a Dunedin man on the West Coast in December 2011.
David Henry Morris was killed when the car being driven by his son was hit by a German tourist in a campervan travelling on the wrong side of the road.
Coroner Richard McElrea said the German couple had rented their vehicle from Wicked Campers, which at the time was not a member of the Rental Vehicle Association, and did not have keep left stickers on the dashboard.
The coroner said such stickers should be mandatory.