Salting and gritting
You should report a problem with any highways in the county directly to Cornwall Council.
Our fleet of 25 gritters - and six reserves - are on permanent stand-by throughout winter, ready to undertake precautionary salting at a moment’s notice.
Please note that the A30 and A38 trunk roads are the responsibility of Highways England.
What we do
We monitor weather conditions all day and night, liaising closely with forecasters, and we also have 11 roadside sensors measuring temperatures and other roadside factors. Once there’s a likely threat of ice or snow, we trigger our treatment procedures.
Cornwall covers a large surface area and we also have a coastline on three sides. The variations in temperature and weather patterns that can exist mean we have divided the county up into ‘weather domains’. When a decision is made, we consider the weather predictions for each area and instruct the gritting lorries to go out as necessary.
This can involve sending one gritter along each of 25 designated precautionary salting routes. On other occasions, we may send smaller numbers of vehicles to target precautionary routes in specific areas, and sometimes there may be no requirement. Depending on how widespread the forecast is and how quickly the weather front is moving across the county, this may mean also mean we salt at different times.
Our precautionary routes consist of the busiest A and B roads on the council’s 7250 kilometre (4530 miles) network. This includes key roads to hospitals, secondary schools and bus stations.
Usually, each gritter will complete its route within three hours. Our aim is to complete salting at least an hour before road surface temperatures are predicted to reach freezing point.
Great care is taken, especially in quickly-changing conditions, to take every reasonably practicable step to prevent freezing roads. Each salting lorry is carefully maintained to make sure that the correct amount of salt is spread on the roads, and all our drivers are fully trained and accredited for the work.
How does it work?
Salt doesn’t melt snow or ice.
When mixed with water, salt lowers its freezing point. The greater the concentration of salt, the lower the freezing point. However, salt can take time to dissolve. Traffic passing over newly spread salt and crushing it speeds this process considerably, sometimes called ‘activating’. Without this additional help, it is possible for salt to lay on a surface and ice form around or on top of it.
Where salt has dissolved into the water, the chances of encountering layers of are ice far less likely. However, the possibility can never be removed altogether because:
- sub-zero temperatures can reach the lowered freezing point required
- salt can fail to dissolve properly owing to lack of traffic to activate it
- rainfall during or after the salting process can wash it away before it can take effect
Our commitment to you
As part of our commitment to you and the winter maintenance service we provide on behalf of Cornwall Council, we will:
- carry out precautionary treatment on the busiest roads when they are near freezing.
- direct most effort to the worst affected areas using quality weather data.
- clear the council’s major routes of snow
- monitor actual conditions closely to ensure planned treatments are effective.
- provide an efficient, cost effective and environmentally sensitive winter service.
- react to flooding and other emergencies.
- reduce any adverse environmental impacts.
- keep delays to a minimum.
Our intended winter maintenance actions are posted automatically on Twitter (@CORMACltd) as soon as we make the decision.