Frequently asked questions about winter gritting

Watch our video about gritting operations.


Why don’t we grit every road in the borough?

Highway law requires a highway authority to ‘ensure that passage over the highway is safe so far as is reasonably practical’. The resources that would be required to treat every road in the borough would be unsustainable. All winter service networks (roads and pavements) are planned so as to provide the greatest benefit for the maximum number of road users and resident.

Why don't we treat residential roads when the snow has compacted and iced over?

During a period of protracted sub zero days following a snowfall, roads have to be regularly retreated to keep them in a safe condition so our resources are employed on the prioritised network.  

A gritting vehicle spreading salt onto compacted ice will have marginal effect. Once a road surface is iced over it is effectively lost until rising temperatures produce a thaw. The opportunity to clear snow has to be taken within the first 12 hours after the snow fell. Ice can be smashed from the road using JCBs but that is costly and damages the road surfaces, it is not possible to disperse ice with a small amount of salt. 

To prevent this happening snow needs to be moved within the critical period 12 to 24 hours after it falls. Residents self help groups can play a vital part in opening up a path to the prioritised network and we are working to encourage and promote the Snow Friends scheme.

Why does snow cause disruption when it has been forecast in advance?

Gritters cannot be at every point on their route at once. In bad weather conditions and especially when there is congestion on the network, route cycle times can rise from the normal 2.5 hours to up to 6 hours.

Our response to a confident forecast of snow is to treat Priority 1 routes and if time allows, secondary routes with 40grams of salt / square metre. This will help to disperse the snow but it will not stop heavy snow from settling, the action of traffic is required to activate the salt.  Once snow is settling our subsequent runs will be undertaken with ploughs and squeegees* fitted.  

* a squeegee is a rubber blade mounted on a plough bracket on the front of a gritter, they are used when snow is relatively light and slushy 

Why are carriageways not treated right up to school gates?

Many schools are on arterial roads and thus treated to the gates, where schools are on side roads or residential roads it is not practical to treat these access roads but in most cases footways leading to the school are treated. The areas of treated footway are closest to the school where footfall is at its greatest.  

How can I find out about routine gritting?

Follow us on twitter @BromleySnow, this is maintained by Bromley Gritters.