Gritting FAQs and myth busting

FAQs

Common questions about gritting:

Our gritting crews are on call 24/7 from mid-November until mid-March.  We monitor weather conditions using a special winter weather forecasting service provided by the Met Desk.  This daily forecast flags up the possibility of freezing road temperatures, snow, and likely time and is a much more localised forecast than those used in the local media.

You can find out the latest by following us on twitter @SolihullCouncil and using the twitter hashtag - #wmgrit

There are nine routes covered by the gritting crews which cover 56% of the borough’s roads - that’s a distance of 560km/348 miles.

To see the gritting routes that Solihull and our neighbouring authorities cover use our online map.

When you’re out and about travelling in other towns and cities you can use the government’s website to find local gritting details - https://www.gov.uk/roads-council-will-grit.

Our grit bins are placed in areas which have scored highly for steep hills, sharp bends and heavy traffic. They are also placed by schools, hospitals, railway stations and older people’s residential homes which aren’t on the routes for treatment. Additional bins are added where we know there are accident hotspots. 

Members of the public can use the grit/salt mix on the roads and pavements but not on private areas such as their drives. If you use it on your drive it’s theft - and you also run the risk of staining your drive red.

Three reasons:

  • We already grit 348 miles of roads - that’s over half the roads in the borough.  It's not possible for the gritters to spread salt on every road and pedestrian area so instead we've provided salt bins at key locations throughout the borough.
  • The science bit - for salt to be most effective it needs traffic moving over it.  You won’t get the level of traffic needed to make it effective on many roads across the borough.
  • If you live on a small side road with double parking and pedestrians right next to the road, would you really want a giant gritter driving down?  They are wider than bin lorries and weigh 28 tons when full of grit!
  • And lastly - gritters can’t turn in cul-de-sacs.

Yes. Treatment involves precautionary salting to prevent ice from forming, salting to melt ice that has already formed and in some cases the removal of snow.  Depending on whether we are expecting rain, hoar frost, fog and freezing conditions we have different courses of action ranging from salt early evening to early morning inspections with crews waiting for instruction.

Key bus routes are gritted within the nine priority routes - see online map.

Yes, as part of the normal winter maintenance, pedestrian areas in town centres are gritted in Solihull, Shirley, Knowle, Hobs Moat, Marston Green and Dorridge.  Other areas are treated in exceptional circumstances when we have more than 10cm of snow or when we have severe conditions for a long time. 

As well as town centres, we have three other levels of priority pedestrian areas. The first covers the council’s town centre main areas along with bus stations, railway stations, schools and hospitals. The second includes other commercial areas and the third covers areas around council owned residential homes and day centres.

Yes, cycle paths are treated on request after an inspection by a council cycling officer. 

We grit roads along nine routes. Small roads aren’t included as gritting trucks are huge and the grit needs traffic to make it work properly. You can check here to see where we grit - Winter Service Plan

You can browse the routes if you look at the Winter Service Plan

Car parks are the responsibility of the owner.

When we get requests for additional gritting the police are given priority. Additional requests are considered if they meet the criteria outlined in the Winter Service Plan

During the coldest months of the year, there are 3,500 tonnes of rock salt kept in stock at all times.

We have nine new 18 ton gritting trucks - 28 tons when loaded with grit!  Balfour Beatty has been appointed as the main contractor and their trucks are equipped with tracking equipment which will provide a more even distribution of rock salt when in use. 

Salt is spread onto road surfaces before the road becomes icy or snow starts to fall. This is known as precautionary salting. We aim to treat the network before sub zero or snowy weather is forecast to arrive.

Except in the case of sudden changes in the weather, when an immediate response may be called for, gritting normally starts early morning or early evening.

For salt to be most effective it needs traffic moving over it to move the salt and salty water around. 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.

This could be for one of two main reasons:

  • This happens when gritters are either travelling to and from the depot, travelling between treated parts of the network, or travelling back over a section which has already been/will be treated
  • It sometimes looks like they’re not spreading because they have a 'low throw' spreading device which distributes the salt on the road at a lower level than traditional gritters. This ensures the majority of the salt is kept on the roads and is more difficult to see than traditional spreaders

Anyone can clear snow and ice from the pavement outside their home or public spaces to prevent slips and falls - normal table salt will work.

Don't be put off clearing paths because you're afraid someone will get injured. Remember, people walking on snow and ice have a responsibility to be careful themselves.

To clear snow and ice safely, follow advice from the Department of Transport

But - don’t use the grit/salt mix from the grit bins for your drive etc.  T hat’s theft.  You also run the risk of red staining.

Myth busting

Common myths about gritting:

Salt works by lowering the freezing temperature of water.  This prevents ice or frost forming on the roads as it would otherwise, once the temperature of the road or the air falls to 0 C.

Salt usually loses its effectiveness once the temperature falls below -5C and stops working at -10 C. Pre-salting the road forms a separating layer so if snow falls it doesn't freeze onto the road surface and can be ploughed off or churned off by traffic.

Salt comes in grain sizes of 6mm or 10mm and is spread at rates of between 10 and 40 grams per square metre depending upon the forecast road surface temperatures and if snow is forecast or is falling.

When spread on top of ice or snow, each grain begins to melt the surrounding ice working its way outwards. As it melts the ice, it forms a pool of salty water which in turn helps to melt the surrounding ice and so on. Without any traffic to move the salt and salty water around and mix it into the thawing ice, the melting process can take some considerable time.

Where snow falls on top of salt then it begins to melt the snow from beneath. Again, road traffic will speed up this process. However the first vehicles over the snow will actually compress the snow into ice in much the same way as a snowball is created. If there is little traffic, or very slow moving traffic, then a layer of ice may form on top of the road until the salt works its way up from below.

There is a relationship between the temperature and the amount of moisture the air can hold. However it is only once the temperature gets below -40 degrees centigrade that the air has so little moisture content that snow can rarely occur.

In this country, most rainfall begins as snow in the upper atmosphere throughout the year. As the snow falls through the lower atmosphere the air is warmer and it turns to rain.

In the winter, the air in the lower atmosphere is also cold, and, if it is at or below zero then the snow can make it to the ground. However very slight temperature changes at ground level due to factors like wind and altitude can change the type of precipitation over short distances. This is why weather forecasters are often very cautious and say it could hail, sleet or snow.

Except in the case of freezing rain! This phenomenon thankfully occurs rarely and is often associated with the approach of warm air after a prolonged cold spell. Here the precipitation once again starts off as snow in the upper atmosphere, then it passes through a region of warm air which turns it to rain before finally passing through a thin layer of cold air just above the surface. The moisture cools to a temperature below freezing point, but the water droplets do not freeze themselves, and become supercooled.

When the droplets strike the ground or any surface, they instantly freeze and coat everything in a film of ice. This coating covers the grains of salt making them almost ineffective until the air temperature rises and the ice begins to melt. Road travel during a period of freezing rain will be severely disrupted and it is unsafe to send heavy gritting vehicles out.

We have nine gritting vehicles to cover 560km/348 miles of the road network across the borough so no, you might not have seen one.

The gritter may not have reached the starting point of its treatment route, or may be returning to the depot at the end of its route or to refill.  It may have run out.

The salt in the bins is for use on public roads and pedestrian areas. It is not there to be used on private properties - that’s theft and...it can stain your drive.

The bins are refilled at the start of the winter season and then usage is monitored. We refill them on request from the public during periods of high demand.