Driving in Rain and Floods in New Zealand

This winter has been especially rainy in New Zealand. Heavy rain and flooding have affected many parts of the country. Driving through heavy rain and surface flooding can be dangerous if you don't know what to expect. Here’s how to drive safely in heavy rain conditions. 

Driving in heavy rain

New Zealand gets a lot of rain and it's inevitable that sometimes you cannot avoid driving in these conditions. Here are some tips to keep you safe during heavy rain. 

• Drive slowly through large puddles. Driving slow will reduce the chance of aquaplaning, which causes the driver to lose control of steering, braking or accelerating the vehicle.

• Keep your car tyres inflated and ensure you have enough tread. Aquaplaning is caused by a lack of traction and can be exacerbated by bald or deflated tyres.

• Leave at least four seconds of space between you and the car in front of you. The New Zealand Road Code advises drivers to leave four seconds of space between vehicles in front during bad weather. This is two seconds longer than normal driving conditions recommendations.

• While the Road Coad does not mandate driving with headlights on during heavy rain it is advised. They do advise adjusting your speed to the conditions and driving slower in heavy rain.

• Brake carefully and take your time going around corners and bends. Your driving is compromised when the weather is bad. Avoid braking suddenly as this can lock up your car.

• Turn on your demister. This will prevent the interior of your vehicle from misting up and will ensure you always have visibility.

What is aquaplaning?

Aquaplaning is when a layer of water between the road and your tyres causes your vehicle to lose grip on the road. Essentially, it’s as if your car is floating. This lack of grip can cause the driver to lose any control over the vehicle.

It only takes a small amount of surface flooding to be at risk of aquaplaning. This means you can lose control even when driving over a deep puddle. To avoid aquaplaning:

• Check your tyre condition regularly. To pass a warrant of fitness on your vehicle your tyres will need to have a tread depth of at least 1.5mm all around your tyre.

• Get your tyres checked more than you need to. In New Zealand, your car only needs to pass a WoF every three years. This means you could be driving on dangerously slippery tyres when it's wet.

• Pump up the air in your tyres regularly. Pumping up your tyres is free at all petrol stations and if you don’t know how to pump your tyres you can ask the staff for help. Having pumped-up tyres ensure the tread is more effective.

• Slow down when it's wet. While it is especially important to drive slowly in heavy rain, you should also drive slowly when it rains after a dry spell. Dirt and oil can rise to the top of puddles and create especially slippery conditions on roads.

• Go around large puddles if you can. If you are approaching a large puddle and it’s safe to do so, go around the puddle rather than through it.

• Turn off cruise control. Driving with cruise control can force your car to use more power. Power plus speed can result in your tyres losing traction.

• Drive gently. Don’t do anything at speed when it’s very wet. Drive, brake, accelerate and turn smoothly and avoid sharp movements that will cause your tyres to lose grip.

Driving in floods

In general, you should never cross a bridge when the river below is heavily swollen and beginning to flood the surface of the bridge. Bridges can break and vehicles can be swept away. It’s always better to stay put or drive to higher ground rather than attempt a dangerous bridge crossing. If you have to drive through a flooded area here are some tips for safe driving.

• Where possible avoid flooding and choose a safer route, especially if you aren’t confident driving in surface flooding conditions.

• Don’t drive through fast-moving surface flooding of more than 10cm. Fast-moving water can easily swell at a moment's notice.

• If the road is so flooded that you can’t tell where the road is and the curb begins, avoid driving through the area. You can damage your car by hitting the footpath.

• Consider what damage the flood may do to your car if you drive through it. Cars, especially modern makes with electronic components, can be susceptible to heavy wet weather and fail. This can put you at risk of breaking down in wet weather.

• Wait until other drivers have reached a safe distance before you take your turn. Don’t drive if there is a wake or spray coming from vehicles on the opposite side of the road.

• Don’t trust other drivers. Always assume the worst can happen and give other drivers space in case they lose control of their vehicle.

• Approach surface flooding slowly to avoid aquaplaning. If you do feel your car begin to aquaplane don’t make any sudden movements with the steering wheel. Ease off the accelerator, grip the steering wheel and your car should eventually regain traction.

• Drive through standing water at around 5kpm. Too fast and you could lose control. Too slow and your car could stall and you can get stuck.

• Drive smoothly through the water in high gear as this prevents water from getting into the exhaust. In an automatic, accelerate slightly but keep the speed controlled with your brakes.

• When you have passed the flooded area, pull over to test your brakes and make sure they are dry.