As winter bites and severe frosts become more common, so motorists need to be prepared, police and the NZ Transport Agency say.
Otago Coastal road policing manager Senior Sergeant Steve Larking said recent "severe frosts'' had made driving conditions challenging.
As the likelihood of frosts increased, motorists needed to keep speeds down, allow plenty of stopping distance and be mindful of black ice.
"When a clear and cold day follows a day of rain, surplus moisture on the roads will freeze over and create a high probability for black ice,'' Snr Sgt Larking said.
Motorists, particularly those on an early commute, needed to take extreme care when driving.
Any patches of road which appeared wet would likely be black ice, Snr Sgt Larking said.
Motorists should check their vehicles and tyres were roadworthy and ensure all windows were clear of ice before driving.
Police set up a checkpoint in Dunedin this week to hand out Dunedin City Council-supplied scrapers for clearing ice from frozen windscreens.
Snr Sgt Larking said this would continue on frosty mornings.
"We did notice that there were a number of cars heading into town for the morning commute that weren't clear [of ice]. It's an offence if you're driving and you can't see out of the windscreen,'' he said.
NZTA senior network manager John Jarvis said motorists needed to plan if they wanted to travel safely and avoid delays caused by road restrictions, road closures or vehicle breakdowns.
Motorists in Central Otago, Queenstown, Milford and Te Anau should carry chains over winter and check road conditions before setting out.
"Extreme weather conditions such as ice, snow, fog and wet weather can hit within a relatively short period of time, so people need to be prepared.
"Also be aware of grit on the road, particularly after a frost event and especially on corners. Slow down on a gritted surface,'' Mr Jarvis said.
Safe winter travelling
• Ensure your vehicle is safe for winter driving.
• Drive to road and weather conditions.
• Allow extra time.
• Slow down and be prepared for unexpected hazards.
• Allow greater following distance between you and the vehicle ahead.
• Make sure your cellphone is well charged; check car charger also.
• Have blankets, snacks, bottles of water ready in case of emergency or breakdown.
SOURCE: NZTA
