Which roads will be salted?
View our salting and gritting routes via the Surrey Winter Online map. Here you can check road priority status and see exactly where we grit and when. There is a key to the map layers, found by selecting the 'Legend' option on the menu at the bottom of the screen.
For more information about the salting process - See our Salting and Gritting FAQs page.
- When and where we salt
- How salt works
- Priority 1 Roads
- High Routes
- Priority 2 Roads
- Other Roads and pavements
- Salt shortages
- Frequently asked questions
How do we decide when to salt?
We use weather forecasts, computerised ice prediction systems and information from roadside weather stations to get the most accurate indications of where and when ice is likely to form.
When deciding if salting is needed, we also consider:
- Whether or not the road surfaces are wet or dry.
- The likelihood of rain or snow.
- If there is any salt already on the roads from previous salting runs.
How do we decide where to salt?
There are approximately 3000 miles of roads in Surrey, therefore we need to prioritise which roads we salt and when. The full map of our gritting routes, and road priority designations can be viewed on the Surrey Winter Online map.
How salt works
Salting does not mean that the road surface will instantly become ice free. Salt works by turning the ice or snow surrounding each salt granule into a saline solution which has a lower freezing point than water. The action of traffic helps the salt to be more effective by moving the salt around and eventually melting all the ice or preventing ice forming.
- It takes time for the salt to become effective after roads are treated (the more traffic a road has, the quicker the salt will take effect).
- Rain can wash salt off roads leaving them prone to re-icing. If the rain turns to snow during rush hour, any earlier treatment will be washed away and it isn't possible to re-salt in heavy traffic.
- If road temperatures fall below minus 7 degrees Celsius the effectiveness of salt diminishes and it will not prevent roads from icing up.
- If conditions are really bad, access to the roads is not always possible - even for the salt spreaders.
- Most minor roads and pavements are not routinely salted.
Priority 1 roads
Priority 1 roads are the most important roads in terms of the volume of traffic carried, and are the first to be treated in advance of any forecast frost, ice or snow. Priority 1 roads include:
- all A roads, B roads and roads carrying more than 8,000 vehicles per day
- main access routes to hospitals
- major bus routes
- roads that link salting routes with those of adjoining counties
- any priority 2 road which meets three or more of the criteria for priority 2 roads.
High routes are a small area to the east of the county that cover the downs at a high altitude. Four gritting vehicles are dispatched from the council's Godstone depot. This particular area of the county is more prone to frost. Because of this, there may be times where we carry out additional salting on these particular routes.
Priority 2 roads
During periods of prolonged and persistent frost, ice or snow, we extend salting to include these roads, but only once priority 1 roads have been cleared. Priority 2 roads include:
- roads carrying more than 4,000 vehicles per day
- main access routes to important industrial areas and secondary education establishments
- single access points to villages
- access roads leading to railway stations
- roads used by other bus routes and depots
- steep hazardous gradients and on bridges where local icing conditions are known to occur.
Other roads and pavements
Priority 3 roads
During periods of snow clearing, the priority 2 network will be extended to include access routes to primary schools.
Roads we partly salt
Some roads are only partly salted. The part that is salted is shown on the Surrey Winter Online Map.
We do not routinely salt pavements. However, when there is prolonged frost, ice or snow, we do try to clear pavements in towns and those areas serving hospitals. More details are on our pavement and footways snow clearing page.
Areas that we do not salt
We do not salt residential roads, alleyways, car parks and private property unless they are on the priority list above.
Full details of our salting criteria will be published in our Highways Cold Weather Plan, which will be available on this page in September 2020.
Motorways and trunk roads
Highways England are responsible for salting the motorways and trunk roads that pass through Surrey, including the M3, the M23, M25, A3, A23 at Hooley and the A30 (in Spelthorne only).
Salting during severe snow conditions or salt shortage
We will restrict salting to a limited number of priority 1 roads:
- A roads
- Main access routes to large and medium population hubs
- Main access routes to A and E, acute and some other hospitals, and all fire stations.