During long dry spells, dust, dirt, oil and other materials build up on the road surface. When it rains, the road surface becomes greasy, making it very slippery – the greatest risk to drivers being shortly after the rain starts. The term ‘summer ice’ is used to describe these conditions that are similar to the black ice that you get in winter.
Even a little rain after several days of dry weather can trigger these conditions, creating a potential danger for unsuspecting drivers.
As this is a cumulative build-up of material on the road surface, there is no treatment for managing it. The NZ Transport Agency will issue warnings about these conditions. However, we are reliant on drivers being aware of summer ice and adjusting their driving to keep safe in these conditions.