Published 2018-11-22

This post is also available in Swedish

Mixed messages on studded tyres

Research shows that studded tyres’ better grip on ice saves lives. But if the effects of studded tyres are considered in a broad life-cycle perspective, the finding is that more lives are lost than saved. This is evident from a study by Mistra Environmental Nanosafety.

Researchers working at Chalmers University of Technology and in Mistra Environmental Nanosafety have adopted a holistic approach to how studded tyres affect human health.

By taking a system perspective on the issue, researchers Anna Furberg, Sverker Molander and Rickard Arvidsson have analysed the health impact of the studded tyres throughout their life cycle.

The analysis showed that studded tyres reap more lives than they save.

It is positive that, in Sweden, use of studded tyres in traffic saves 60 to 770 potential years of life lost (YLL). However, in a broader life-cycle perspective these tyres are found to cause 570–2,200 YLL, which is clearly negative.

This adverse health impact alone, mainly due to the rise in atmospheric particle concentration that occurs when studded tyres are used, overshadows the benefit. If other aspects are added, the result becomes even clearer, the researchers emphasise.

The researchers have, for example, examined accident statistics from small-scale mining in Congo-Kinshasa where cobalt, an important constituent of the studs, is extracted. In their assessment, the researchers have also considered the fact that cobalt is a sought-after metal, which exacerbates conflicts in the country.

‘Small-scale mining, where there are many accidents and deaths, accounts for the second-largest share of the studded tyres’ negative health impact. Deaths associated with the conflict in Congo-Kinshasa account for the smallest proportion, but at the same time there are more aspects that aren’t included in the study. The conflict affects the whole of society, and I don’t believe many people give a thought to the contribution made by the use of studded tyres to the situation in that country,’ Furberg says.

The benefit of studded tyres is mainly in Scandinavia, while almost a third of their negative health impact arises outside the region.

‘This is a clear illustration of what globalised production can lead to. Here, there are some who survive at the expense of others, and people other than those who benefit from the product are the ones who suffer the negative effects,’ Molander says.

What, then, are we as consumers to think about these research results? Furberg and Molander emphasise that good winter tyres without studs may be an option, combined with careful driving and sometimes considering alternative modes of transport.

‘Of course it’s important how we drive, and that snow ploughing and sanding work properly. Today, there are also electronic anti-lock braking (ABS) systems in most cars, which make them safer to drive on slippery roads. But our study also highlights the need for more research on alternatives to studded tyres that don’t have the same negative health aspects,’ Furberg says.

The research was carried out within the framework of the Mistra Environmental Nanosafety programme.

Facts about the study

In the study, the researchers scrutinised:

  • Lives saved — accident statistics and studies on differences in accidents involving cars with and without studded tyres.
  • Emissions in the use phase of studded tyres, because of particle pollution from road wear, and literature reviews of particle wear on roads associated with the use of studded tyres.
  • Emissions during production, from mining and manufacture, and literature reviews of various types of emissions and their scale.
  • Accidents and deaths during production, such as in cobalt mining; literature reviews of accidents and deaths in various industrial activities; and statistics on accidents and deaths in small-scale mining.
  • The number of deaths connected with the conflict in Congo–Kinshasa.
  • Road emissions make up the highest proportion of the studded tyres’ negative health impact (67–77 per cent), followed by accidents and deaths in cobalt mining (8–18 per cent). Between 23 and 33 per cent of the negative effects occur outside Scandinavia.

Facts about studded tyres

In two major reports, the Swedish National Road and Transport Research Institute (VTI) examined the difference in road grip between studded and non-studded tyres. According to these reports, studded tyres have a clearly better grip on ice than both the Nordic and European types of non-studded tyres, but on snow-covered surfaces the differences between the various types of tyres are smaller. When the road is wet, the tarmac is salted and the temperature is around zero, the braking and steering performances of studded and non-studded Nordic tyres are virtually equivalent.

According to a Norwegian study, studded tyres reduce the number of accidents involving passenger cars by 2 per cent on snow-free ground and 5 per cent on roads covered with ice or snow, compared with non-studded winter tyres.

Link to the study

The Mistra Environmental Nanosafety programme

Text: Per Westergård