Winter Service - Salting/Gritting
A. The primary salting network is made up of the major routes where the majority of vehicle movements take place and also includes accesses to hospitals, ambulance stations, fire stations, other emergency service establishments, railway stations, airports and secondary schools. The length of the 37 routes which form the primary salting network is 20% of the road network.
The following criteria are used to determine which roads are salted:
|Strategic Routes||All A and B roads and C roads classified as high speed routes|
|Traffic Flow||Routes with February two way flows greater than 1000 vehicles per day|
|Settlement Population||Main access route to settlements with a population of 500 or greater as provided by Devon County Council’s Strategic Intelligence unit|
|Emergency Premises||Main access route to 24hr emergency services premises, defined as “Emergency premises with 24 hour access” include: ambulance stations, full time and retained fire stations, hospitals with 24 hour casualty departments and police stations manned 24 hours.|
|Cottage and Community Hospitals||Main highway access route to strategic cottage and community hospitals as notified to the authority by Devon Primary Care Trust|
|Secondary Schools (including Independent Secondary Schools)||Main highway access to secondary schools|
|Bus Routes||Bus routes with a service interval of at least 15 minutes within any one hour of the day, in one direction of travel or where a combination of multiple bus services meet this criteria|
|Airports||Main highway access to regional airports|
|Railway Stations||Main highway access to mainline and branch line railway stations|
|Adjoining Highway Authority Salting Networks||Agreement to ensure consistency of action across boundaries|
|Park and Ride sites||The bus loop of Park & Ride sites.|
A. Yes, there is a secondary network which includes a lot of the minor roads to smaller communities. This secondary network is treated during extended periods of cold weather (defined as snow or ice most of the day). But not until the main route is clear.
The following criteria are used to determine which roads are salted as part of the secondary network:
|Settlement Population||Main access route to settlements with a population of 100 to 499|
|Park and ride sites||Car parking area|
|Bus Routes||Where problems have been identified on routes with a service interval of at least 30 minutes within any one hour of the day, in one direction of travel, or where a combination of multiple bus services meet this criteria.|
|Main highway access route to Devon County Council Level 1 properties||Those council properties providing essential services which cannot be closed in severe weather - as defined during the swine flu pandemic emergency response.|
A. In the event of a salt shortage or other resource problem, a reduced salting network, referred to as the ‘resilience network’ (of just over 50% of the primary salting network) will be implemented to the following criteria:
- ‘A’ roads
- Main access to 24 hour emergency premises
- Main access to primary market and coastal towns.
A. The roads on the primary salting network are shown on the attached map.
A. No. Torbay and Plymouth Councils maintain roads in their areas. The Motorway and Trunk roads (which includes the M5, A30, A303, A35 and A38) are maintained by the Highways England. Devon County Council is responsible for 13,000km or 8,000 miles of road in Devon.
A. All of the gritters that are used for salting the network are fitted with GPS tracking devices so that we can see where they are at any time. The devices also record where and when the gritters passed along a route for record purposes. The gritter drivers are instructed to drive with due care and attention. The maximum speed when salting is 45 mph, conditions permitting.
A. The standard treatment time is 3hrs, although some routes are completed in a much shorter time.
A. Busy footways e.g. main shopping centres are treated on a reactive basis during periods of prolonged freezing (defined as snow or ice most of the day) within the resources available, once the primary salting network is clear.
A. Devon County Council, as highway authority, maintains nearly 13,000 km or 8,000 miles of roads in the county.
During a winter emergency situation it is not practicable or cost effective for the whole network to be pre-treated or cleared immediately. The primary salting network is made up of the major routes where the majority of vehicle movements take place and also includes accesses to hospitals, ambulance stations, fire stations and other emergency service establishments, railway stations, airports and secondary schools. The length of road forming the primary salting network of 37 routes is 20% of the road network.
A. The forecaster, Meteo Group, issues a weather forecast, predicting road temperatures and when they are likely to reach freezing point. This forms the basis of the decision whether to salt/grit or not, what time to salt/grit and which parts of the route need to be treated.
A. Most authorities use pure salt to pre-treat the highway network tomitigate the formation oficeand snow, although traffic is needed to make it effective. In snow conditions grit is often added to the salt to aid traction. Pure salt is the most effect pre-treatment, grit is often added once snow has started to lay and compact. The term "gritter" is used generically but most of the time they are spreading salt. In Devon and some other authorities, brine is added to the salt as it leaves the vehicle in what is described as a "pre-wet" operation. This makes the salt quicker acting and it sticks to the road surface.