Facts about gritting the road

During the recent snowy weather, we thought we’d look into Grit. Here are some facts you might not know about the stuff they use to keep the roads ice-free.

  • Is it grit or salt?

Although it’s commonly called grit, what is used on the roads is normally rock salt, which lowers the freezing point of moisture on the road surface, to stop ice forming. It can also melt existing snow and ice although this can take a while.

  • There’s a science to gritting!

You may think just stick it down but there are actually sensors local authorities use to decide when to send out the gritters. These sensors measure road temperature, and air temperature, rain, dew and salt levels. GPS mapping is used to predict areas to focus gritting on.

Ideally, grit needs to be laid onto an already wet road so it sticks otherwise passing traffic blows it off thanks to the air they displace.

  • Where does it come from?

Surprisingly it’s British. And no it’s not from the sea. It’s actually mined, there are 3 mines across the UK; Cheshire, Teesside or County Antrim (Northen Ireland).

It transported by rail or road to your local authorities depot.

Did you know the vast caverns left over from mining are the ideal place for storing archive documents? With low humidity, no water and no UV light.

  • Once and it’s done?

Surely you grit once and it’s done, right? Unfortunately not, road salt need’s to be constantly applied otherwise the salt gets diluted by the falling snow or rain and this raises the freezing temperature. The constant application of grit keeps the dilution of the salt at an ideal level.

  • Gritting priority.
You know local authorities don’t grit every street, what priority are roads gritted?
As you might have guessed, it’s the critical road network, Motorways and A roads as well as those used by public transport.
Links to hospitals and emergency services are also a priority.
Once the main network is gritted, roads to schools and old people’s homes are next.
  • It has limits

Even salt has its breaking, or rather freezing point, which is around minus 8-10 degrees, depending on the dilution of the solution. In these temperatures, roads will still ice over regardless of whether or not they’ve been gritted.

Did we miss any? let us know!