About driving

When conditions change

Road surface

There are three main types of surface used on New Zealand's roads and highways:

  • asphalt
  • chip-seal
  • unsealed surfaces.

You may need to adjust your driving to suit the particular surface you are driving on and how each type of surface can affect your vehicle's handling. You should also be alert for changes in the road surface.

Asphalt

Asphalt has a smooth, black appearance and produces a low level of road noise when you drive over it. It's often used on busy roads and curves because it stands up well to wear caused by braking vehicles.

Asphalt provides good overall grip, but has reduced skid resistance when it is wet. This means you should slow down and take extra care when driving on asphalt in wet weather.

Picture of an asphalt road

Asphalt

Chip-seal

Chip-seal consists of a thin layer of stones set in tar. It has a rough appearance when in good condition, but may wear smooth with age and frequent use.

Worn chip-seal has reduced skid resistance, so be alert for smooth patches as you drive.

Slow down on newly laid chip-seal. There may be patches of loose chips, which can increase your risk of skidding. Loose chips can also be thrown up when vehicles drive over them and could break your windscreen.

Picture of a chip-seal road

Chip-seal

Unsealed surfaces

Depending on the geographic area unsealed roads can be clay, pumice or gravel (sometimes called ‘loose metal’). These roads tend to be minor roads in rural areas.

Because the surface of the road is loose, it can move under your wheels and offers very low skid resistance. Loose stones may also be thrown up by vehicles. Because of this, you need to drive very carefully on gravel roads. Adjust your speed to suit the conditions.

You will also need to take extra care in dry weather, as your visibility may be reduced by dust that will be thrown up by any vehicles in front of you. Always increase your following distance to stay back from the dust cloud.

Picture of a gravel road

Gravel


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Last updated: 4 October 2012