Road gritting and salting

Staying safe on our roads in Winter

Winter weather can be frustrating, especially when roads feel icy or travel is disrupted. Our teams work around the clock to reduce risk to keep Croydon moving. 

Our Winter service usually runs from October to April, but this can be longer if cold weather continues . It operates 24 hours a day, seven days a week, and includes road gritting, and maintaining grit bins at priority locations.

When forecasts show a risk of ice or snow, our gritters are deployed. We manage around 5,500 tonnes of grit, operate 7 gritters and during a single run can treat around 240km of the road network However, we have around  730km of roads, so not every road can be treated at the same time.
 

Road gritting and salting

About 30% of the borough's roads are salted (often known as gritting) when snow or ice are predicted, or when there is sudden and unforecast snow.

These roads cover about 240km, and they have been chosen because they are the most important ones to keep traffic moving.

The typical criteria for selecting these roads are:

• A or B roads
• main bus routes
• approaches to rail stations
• approaches to fire, police or ambulance centres
• steep gradients

We give priority to the roads on the primary gritting routes during times when temperatures remain below freezing for an extended period, or when there is heavy snowfall. Of these roads there are 4 priority routes (about 70km worth) that are treated first. When we are satisfied that these primary routes are clear the remaining 7 routes be covered.

When salt is put down

Before gritting, our teams carefully assess detailed information, including weather forecasts, ice prediction systems. Road temperatures can differ from air temperatures, so this data helps us target treatment where it is most needed. We also consider wether:

• roads are wet or dry
• rain could wash grit away
• any previous treatments are still effective.

Salt is spread on to road surfaces before the road becomes icy or snow starts to fall. This is known as precautionary salting. Depending on traffic, it takes our gritters about 2 hours to spread salt on the priority routes. We aim to treat the network before sub zero or snowy weather is forecast to arrive.

If the time of salt spreading coincides with peak rush-hour traffic periods, gritters may become delayed in traffic and can get stuck along with other road users they are there to help.

How much salt is put down

Salt is spread at 8 grams per square metre for a frost warning. Salt can be spread at up to 40 grams per square metre for a forecast snow warning.

We have electronic tracking devices on our salting vehicles, as well as technology that allows us to see just how much salt has been put down at any location. If your road is on one of the priority lists and you do not believe it has been treated, contact us using the details below and we will check on the situation.

Effective salting of roads

Salt lowers the freezing point of water but is not as effective on top of ice or snow. To be most effective it needs traffic moving over it. Prolonged and heavy downfalls of snow will naturally affect the effectiveness of grit salt. As it dissolves it becomes less effective because it is diluted.

Why roads may still be icy

Grit does not work instantly. It lowers the freezing point of water and needs traffic to help spread and activate it. In very cold weather (below -5°C), during heavy snowfall, or when rain washes grit away, roads can still become icy.
 

Salt supplies

We have 5,500 tonnes of salt in stock ready for the winter ahead. With careful planning this should see us through to the spring, but if we do experience severe weather across the UK then there will of course be the danger of stocks running low and difficulties with getting new supplies delivered.

Pavements

If the forecast indicates prolonged bad weather then street cleansing and grounds maintenance staff from parks will be called upon to help with manual snow clearance and salting of the pavements.

This will be done on a preventative basis for priority areas such as town centres and around stations.

Salt bins

The council has 604 salt bins which are filled at the start of each winter. They are then inspected and refilled after periods of adverse weather.

Locations of our salt buns (PDF, 252KB)

These bins have been placed at locations where drivers or pedestrians may need to put down salt during freezing conditions on the roads or pavements only. Do not use salt from our bins for private driveway as this could cause the bins to be are empty when they are most needed for the roads or pavements.

You can report an empty or damaged salt bin, via Love Clean Streets.

Extreme cold

Motorists should take great care when temperatures drop below minus 6 degrees Celsius, as there is a risk that salt will become less effective because the melted snow and ice may refreeze.

Contact us

Our teams continue to monitor conditions closely and respond as safely and quickly as possible.

If you require any more information on gritting routes and the location of grit bins, please contact HighwaysMaintenance@croydon.gov.uk.