Why can't South Africa's roads handle snow?

The snowy conditions that led to the closure of several roads including the N3 at the weekend raised questions about the transport infrastructure’s ability to deal with extreme weather in South Africa.

The toll road linking Johannesburg to Durban was thrown into chaos when road users were trapped in heavy snow. Hundreds of motorists were stranded and at least one person died of hypothermia as icy conditions, wet weather and poor visibility affected parts of the country including KwaZulu-Natal, the Free State and Eastern Cape.

Many roads were impassable, leading to vehicles being stuck on the road for nearly two days, resulting in people being cold and hungry while they awaited help in freezing conditions. Midlands emergency services reported a woman died of the cold in Merrivale, near Howick, after travelling in a taxi which had become stuck.

It raised the question why icy weather has such a dramatic effect on traffic in South Africa compared with countries in the northern hemisphere that are much more heavily affected by snow but do not close their roads, except in exceptional circumstances.

The South African National Roads Agency (Sanral) said South Africa's roads are designed and built for the local climate. Snowfall more than 1m deep, as occurred at the weekend, is not normal and does not happen every year.

“Roads in the northern hemisphere are designed and built for sub-zero winter temperatures and regular and heavy snowfall.  South African vehicles are not equipped to travel on snow-covered roads. Vehicles in the northern hemisphere may have special tyres, or chains in the case of the heavy vehicles,” said Vusi Mona, Sanral GM for communications and marketing.

Winter tyres are designed to cope with colder temperatures. They are made of a different type of rubber compared with regular tyres, with deeper tread grooves that help vehicles grip the road better in the cold and ice. In many European countries it is a legal requirement for motorists to have winter tyres on their vehicle for specific periods of the year, while drivers also carry snow chains to help their vehicles grip.

In countries where it snows regularly during winter, road-clearing measures are introduced including deploying snow ploughs and sprinkling rock salt on icy roadways to melt the ice. Salt lowers the freezing point of water, which prevents ice from forming. 

Unlike their northern hemisphere counterparts, South African drivers are also not accustomed to slippery, ice-covered roads and do not have the skills to handle the conditions.

“Sanral and its concessionaire, the N3 Toll Concession (N3TC), closed the N3 at the Van Reenen’s Pass because of dangerous conditions including black ice which made the roads extremely slippery, with trucks losing traction especially on the uphill sections,” said Mona.

After Van Reenen’s Pass was affected by abandoned trucks, traffic was stopped at the Tugela Plaza in KwaZulu-Natal and Harrismith South Interchange in the Free State. Sanral and N3TC mobilised response teams to clear the snow on the affected roads and disaster management centres conducted relief operations. 

The N3 was reopened on Sunday evening and traffic is flowing after the extensive backlog between KwaZulu-Natal and Free State was cleared and trapped motorists were rescued.

Mona said discussions are under way to ensure more resilient infrastructure, given the climate change challenges and how they affect road safety.

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