Our gritters and their crews are ready to take action 24 hours a day, seven days a week using the most up to date technology to identify when and where to start salting.

How we decide when to salt

Daily weather forecasts and computerised ice prediction systems use information from roadside weather stations to get the most accurate indications of where and when ice is likely to form, and whether precautionary salting might be needed. Conditions vary across the county, and the roads are not automatically salted every time there is a forecast of frost.

We also consider the following three things:

• 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 we prioritise which roads are salted

There are 39 salting routes in Surrey. We have a limited budget and a total of 4,800km of road network which can't be treated all at the same time so we prioritise as follows:

Priority 1

To be treated, as routine pre-salting, in advance of any forecast frost, ice, or snow.

• roads that carry the heaviest traffic
• roads linking centres of population
• to all 'A', 'B' roads and other roads carrying more than the 12,000 vehicles per day
• main access routes to Accident and Emergency and acute hospitals
• major bus routes
• roads that link gritting routes with those of adjoining counties.
• any priority 2 road which meets two out of three of the criteria points.

Priority 2

To be treated only when there is prolonged and persistent frost, ice or snow which is expected to continue, or following snow but only once priority 1 routes have been cleared.

• roads with traffic flows greater than 5,000 vehicles per day
• main access routes to important industrial and secondary education establishments
• single access points to villages
• access road/s leading to other hospitals, ambulance stations, railway stations
• roads used by other bus routes and depots
• steep hazardous gradients and over bridges where known local icing conditions occur.

Priority 3

To be treated only when there is prolonged snow which is expected to continue, or following snow but only once priority 1 routes have been cleared.

• access routes to primary schools to be cleared in conjunction with Priority 2 routes during snow clearing.

Pavements are not routinely treated. However, when there is prolonged and persistent frost, ice or in the event of snow, we would try to clear pavements in towns and those areas serving hospitals as a priority.

Motorways and trunk roads

The Highways Agency are responsible for gritting motorways and trunk roads that pass through Surrey, including the M3, the M23, M25, A3, A23 at Hooley and the A30 (in Spelthorne only).

'A roads plus'

During extended periods of cold weather it may be necessary to reduce the roads that are gritted to conserve our salt stocks and to ensure we maintain resilience for any further periods of cold weather. At these times we will grit the 'A road plus' network which represents approximately 17% of all the roads in the county. The 'A' road plus network consists of the 'A' roads and main access routes to A&E, acute and a number of other hospitals and all fire and ambulance stations. It also includes main access routes to large and medium population hubs. The A road plus salting network can be viewed here on the Surrey Interactive Map.

Areas that would not be gritted

This include residential roads, pavements, alleyways, car parks and private property unless they are on the priority list above.

How the 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 from forming. On roads that only have light traffic, the surface will remain icy for some time after salting.

We have invested in a new and improved way of salting the roads using pre-wetted salt. This method, which mixes dry, high purity fine graded white salt and brine, is much more effective than traditional systems. The salt/brine mix tends to stick to the roads, uses less salt and is kinder to the environment.

You should be aware of the following:

• It takes time for the salt to become effective after roads are salted.
• Rain can wash salt off roads leaving them prone to re-icing.
• If conditions are really bad access to the roads is not always possible, even for the gritters.
• In really severe weather, even salt will not prevent the roads from icing up.
• The majority of minor roads will receive no treatment and footways are not routinely salted.
• If the rain turns to snow during rush hour, early salting cannot take place as it would be washed away. Also gritters cannot keep a constant speed to spread the salt in traffic.

Please note that despite the high level of service we aim to provide, no guarantee can be given that the roads will always be completely free of ice and snow.