Intersections throughout the country are being checked to see which could cause a problem when the give way rule changes.
From 25 March, vehicles turning right at intersections will have to give way to a vehicle coming from the opposite direction and turning left.
At present the driver turning right has priority over the driver turning left.
Officials estimate the change will prevent on average one death, 13 serious injuries and 84 minor injuries each year.
Councils have until the middle of next month to identify what intersections will pose a high risk to motorists when the change occurs.
Dunedin and Christchurch City Councils have completed their intersection analysis and say they'll consider changing the traffic flow or widening certain lanes at some crossings if problems eventuate.