Highways Agency

Keeping Our Roads Clear In Winter

During icy winter nights and frosty mornings an army of dedicated men and women working for the Highways Agency ensure motorways and major trunk roads are kept ready for use by drivers and other road users under the organisation’s multi-million pound winter maintenance programme.

The maintenance teams monitor the weather and operate the salt spreaders to make sure traffic can use our roads – whatever the weather.

The Agency, part of the Department for Transport, uses companies around the network to deliver these important services on the trunk road network, the busiest roads in the country which annually carry one third of all traffic and over half of all goods traffic.

Grit or salt?

Although most of us call it gritting, there is in fact, no grit involved. The stuff spread on the roads is rock salt, taken from an underground mine in Cheshire.

It is more or less the same as the rock salt you’d grind onto your food, other than it is brown due to containing an impurity of Marl, which is a type of clay.

We spread salt onto the road, but it works best when it goes into a solution. We rely on the tyres of cars passing over the top of it to crush the salt onto the road. This then forms a solution with a higher de-icing capability.

Water freezes at 0C, but the salt stops the water from freezing until -6C to -8C.

If it snows, we spread 40g of salt per square metre on the roads before the snow comes. Then as the snow falls we continue salting and we use snowplough attachments if the snow accumulates.

Salt spreading in the East Midlands – A case study

Salting the motorways and trunk roads in Derbyshire, Nottinghamshire, Lincolnshire, Rutland and parts of Leicestershire and Cambridgeshire is carried out by AMScott on behalf of the Highways Agency. The city and county councils in these areas have their own vehicles for non-trunk roads.

At the AMScott depots in Sandiacre, Heath, Newark and Ketton there are what looks like huge sand dunes stored in sheds. In fact these are 2-3,000 tonne mountains of salt ready to be loaded aboard the spreaders.

Inside each of the spreaders is a central console which the driver uses to programme the machine. A tracking system records the location of the lorry and the roads which have been treated.

AMScott operations manager Bob Lanes, said: “We take a comprehensive approach to our winter maintenance programme.

“We receive weather forecasts from the Met Office, put that together with our detailed local knowledge of the network and work out what the likelihood of frost or snow is. If necessary, we monitor the situation on an hour-by-hour basis before making decisions to send our crews out to salt the roads.”

The seven months from October until the end of April are identified as the winter season for the Highways Agency. This is when the crews are on standby to deal with winter weather.

To allow them to do this, AMScott managers receive weather reports from the Met Office each day.

“We receive a morning summary text at 6am each day and then receive a 24 hour forecast at about noon, said Bob.

“We also get a two to five day forecast during the day. Depending on the weather conditions, we might receive an evening update too.

“We don’t just rely on forecasts though, we have cameras across the East Midlands so that we can keep an eye on the road conditions, and at the roadside there are weather information systems which feed information about conditions back to us.

“Of course, we talk to our staff at the depots to find out what conditions are like there, and now we have Highways Agency traffic officers to provide the eyes and ears on motorways.

“The most critical time is between 1 Dec and the end of February, when we expect the most severe conditions. However, if the weather is particularly mild then we don’t go out salting for the sake of it,” said Bob.

Plan your journey

Drivers need to check the weather conditions and plan their journey before setting off. Bob says: “We always advise people to keep warm clothes, boots, food and drink, de-icer and an ice scraper in their cars. And if severe weather arrives, people should not drive unless the journey is essential – instead they should wait until the weather improves.

“I think the best thing drivers can do to help themselves during winter weather is to check the forecasts before setting out on a journey.

“We always like to be prepared and because of the advance information we receive about the weather conditions, nothing takes us by surprise.”