Which is the perfect road surface treatment to increase traction?
To keep transportation – and society – running, authorities have different strategies for keeping roads open and driveable in harsh winter conditions. Snowplows keep the snow masses away from the road, and often some kind of surface treatment is used to increase traction when roads are icy and unsafe. But, which is the perfect road surface treatment? The simple answer is... None! Every method of surface treatment is a compromise between effectiveness, cost, handling and side effects. Let's have a look at some methods.
Sand
Spreading sand on icy roads is a tried and tested, effective method to increase traction. Looking through the microscope, a bunch of rugged rocks (yes, that is what grains of sand look like in a microscope!) are added between the tire and the icy road to increase traction. This method is commonly used in many countries, regions and local cities. The downside of sand, aside from the bulky and heavy handling, is that it needs to be swept away in spring keeping city streets clean. Although seemingly environmentally friendly, sand has been questioned and criticized. Potentially harmful particles are spread into the air when the sand is swept and handled. Also, the microenvironment at the roadsides is affected when sand is introduced - to insects and tiny plants, sand grains are detrimental.
Road salt
Salting icy roads is an effective method, but how can salt make the ice melt? Fresh water freezes before salt water because salt lowers the freezing point of water. But why? The freezing point of a liquid (in this case water) is lowered when an additional compound is added (in this case salt). This phenomenon is called freezing point depression.
When road salt is added to the icy road surface, it breaks into its components (typically sodium and chloride ions) in a very small amount of water. This "saltier" solution will have a lower freezing point which will prevent it from freezing to ice. It only takes a tiny bit of liquid to start the process, but where does the liquid water come from when the road surface is frozen?
Looking through the microscope, even in freezing temperatures, the friction heat from tires may well be enough to melt a sufficient amount of ice into liquid water starting the chemical process. In even lower temperatures, it may be necessary also to wet the road with water to start the melting process. However, if it's too cold, water will freeze too quickly, and there will be no liquid water present. This is the main reason why road salt efficiency decreases in lower temperatures making it impractical in temperatures below roughly –10°C.
The main downside of road salt is its environmental impact. Flora and fauna alongside the road simply are not fit for salty water. Also, salt increases corrosion on the vehicles.
Are there other methods?
Of course, authorities must provide a working transportation infrastructure - which includes driveable roads in wintertime. However, individuals also take precautions and don't fully rely on public services when winter strikes. For example, many drivers put a foldable snow shovel and a small bag of sand in the car trunk "just in case…"
Another method to prepare for the (un)expected is automatic tire chains. With Onspot mounted on your commercial vehicle, you will always have the traction when needed. No hassle. No impact on plants or animals. Just sheer convenience – and safety.
