Find out about road gritting
Myths and facts of gritting
How many gritters and ploughs do Swindon Borough Council (SBC) have?
We have 9 gritting lorries, 8 of which are in regular use and we generally keep the ninth as a spare in case of a breakdown. We’ve also got eight ploughs.
How many members of staff are involved in gritting activities?
There’s no-one in the Council’s Transportation Team who works on gritting full time. All gritting staff fit their work in around their other Council full time jobs during the winter season (mid-October to mid-April).
There are two main teams of trained and qualified gritter drivers made up of eight drivers each, who are on standby 24-hours-a-day for gritting operations every other week.
There’s a team of four inspectors to oversee the gritting operations and act as eyes and ears for the decision makers during the night.
The decisions whether to go out gritting and monitor forecasts and conditions is made by a team of four officers who are also on duty 24 hours a day during their rostered weeks.
When snow ploughing is necessary, there is a need to have a ‘mate’ with each driver. In these cases we have to rely on the good nature of any available staff to assist as ‘mates’.
How do SBC decide gritting treatments?
Swindon Borough Council has two forecasting weather stations, one near Blagrove Roundabout on Great Western Way and one on Marlborough Road, just outside Chiseldon. Readings of the current weather conditions are sent from both stations to our specialist Weather Forecast provider every 10 minutes. These readings produce two daily forecasts which show the forecast air temperature, road surface temperature, wind speed and rain/snow. If there’s any uncertainty in the information received, we call the forecaster.
From this information, gritting treatments are planned. If there’s any major changes to the forecast at any time of the day, the forecaster calls the Council’s Winter Service Decision Maker to let them know. Additionally, a two to five day forecast is received daily to help us plan ahead for what gritting resources may be needed.
Why haven’t I seen any gritters out and about?
We’ve got 8 gritting vehicles to treat the 322km of road included on our gritting routes and it takes approximately 3 hours for one vehicle to treat its entire route. The vehicles normally start gritting at least four hours before the forecast says that the road surface temperature is to reach freezing point. If it has snowed, it’s likely that the gritters will be on the road continuously, but it may be 3 to 4 hours before they pass the same point twice as they will have to return to the depot to be refilled with salt. When heavy snowfall occurs, our priority is to keep the strategic network open. The gritters will be concentrated on the main roads and fitted with snowploughs, meaning that estate roads may not be treated as often.
Why do gritters sometimes drive without spreading salt?
Although it may look this way, the gritting vehicles we currently use are far more sophisticated than those of years gone by. The lorries now dispense the required amount of salt directly down on to the road.
However, sometimes a vehicle might not be spreading any salt if it: hasn’t reached the starting point of its treatment route; is returning to the depot to refill; or is driving over a section of road which has already been treated by a fellow driver to get to the next part of their route.
Every gritting vehicle is fitted with a GPS system which tracks its route and speed, and it’s part of the inspector’s job to make sure the lorries don’t deviate from their route.
Why has a salt box near me never been refilled?
With almost 500 salt bins spread across the Borough, there’s always the chance that one may be missed. You can report this by searching ‘salt box’ on our website. The salt in these bins is for use on public roads, pedestrian areas and footways only, rather than for use on private properties. If salt from the bins is seen to be being misused, you can report this to us in confidence. If it’s seen being stolen, this should be reported directly to the police along with the make, model and registration number of any vehicle involved.
If we need to preserve salt stocks to keep the road network open, then the refilling of salt bins may be reduced.
Who is responsible for the M4 and A419?
The A419 and the M4 are both treated by contractors on behalf of Highways England. There is a list of all of their contracts available on the Highways England website.
Why don’t pavements in Swindon get gritted?
There are in the region of 1900km of footway, backway and cycleway in the Borough and with the best will in the world it would simply be impossible to treat them all. There’s almost 500 salt boxes available across the Borough and this salt can be used by residents on pavements and pedestrian areas.
When and why do SBC ‘handsalt’ roads?
All our programmed gritting routes are designed so that we can access the roads using one of our gritting lorries. When we experience severe snow conditions we try to attend other roads, particularly those on hills. However, due to accessibility or safety concerns sometimes we cannot use our gritting lorries. In these cases, we send smaller vehicles loaded with salt which is then spread by hand by our operatives. We usually concentrate on roads for treatment, but when handsalting steep hills, the operatives do apply salt to the footways to improve safety for pedestrians.
When do SBC decide that the plough should be used?
Contrary to popular belief, we cannot scrape snow ploughs along the road as this would just wear the rubber blade out within minutes. Instead the ploughs are set to run about one inch above the road surface, meaning we need to have at least two inches of snow on the road before the ploughs are used.
How does salt prevent the formation of ice?
Salt lowers the temperature at which water freezes, helping to prevent ice or frost forming on the carriageway. However, if temperatures were to fall below -10 degrees centigrade, salt generally loses its effectiveness.
Does spreading salt on top of ice or snow melt it straight away?
Salt will not melt ice or snow straight away. It takes time for the salt to mix with the snow and ice and melt it. However, cars driving over the snow and ice will speed up the process because it mixes the salt in faster.
What type of grit do SBC use?
For our normal salting operations, we use a product known as Thorox+. This is rock salt generally mined within the UK with the addition of a by-product derived from the sugar refining process. There are several benefits to using this product as opposed to the traditional pure rock salt including:
- It’s less corrosive to steel and aluminium
- It causes less damage to concrete and asphalt road surface
- It’s more free-flowing which makes it easier for the gritting equipment to spread without it blocking up the mechanism
- It remains active on the carriageway surface for longer so we do not have to treat it as often
If we have to treat structures like footbridges, we can’t use the normal Thorox+ salt because, even though it’s less corrosive than pure rock salt, it could still damage the reinforced concrete structure. In these cases, we spread a product which contains urea as its active ingredient which is much less corrosive. We can’t use this urea product as our main de-icing material though, as it costs about 16x more per tonne than the Thorox+.