Winter service plan

As the highway authority, we have a duty to maintain the highway and ensure (as is reasonably practicable), that safe passage along a highway is not endangered by snow or ice. It is not practicable, for reasons of cost, to maintain resources to undertake precautionary treatment of the entire highway network. We prioritise certain routes and provide information about winter services, along with interactive mapping on our website.

This plan sets out how winter service is provided by Kier (as the service provider on behalf of North Northamptonshire Council).

Our aim is to provide an effective and efficient winter service to allow:

  • the safe passage of vehicles and pedestrians on priority routes
  • to control delays due to winter weather
  • to carry out operations safely

The service is divided into two main types:

  • Precautionary: This describes action taken by the authority to prevent the formation of a hazard such as frost or ice
  • Adverse: This describes action taken to remove a hazard that has already formed, such as accumulations of snow or ice that have formed on the network

Policy statement

The weather is difficult to predict, and the occurrence and extent of wintry conditions can vary considerably throughout the season and from year to year and across North Northamptonshire. To cope with these changing conditions the council has developed a highly efficient and responsive winter service policy. Winter service is essential for public safety and to the national and local economy in maintaining the movement of traffic and pedestrians. Its operations include treating the network with de-icing agents and clearing roads and footways of snow and ice.

The winter service season runs from 15 October through to 15 April and is a cyclic operation which involves careful planning prior to the start each year.  During the winter service period, North Northamptonshire Council and its Service Provider receive a specialised winter weather forecasting service based on data received from local weather stations. The daily forecast gives predictions of the possibility of freezing road temperatures, snow, etc., and the time that those conditions are expected to occur. This information is used to determine treatment types and timings.

The road precautionary network has been divided into three levels of priority for the treatment of ice and snow.

Precautionary routes comprise of all the “A” roads (level 1) and the majority of “B” roads (level 2) together with some other important roads. Undertaking precautionary salting on the network prior to the on-set of the forecasted hazard. However, during periods of prolonged, extreme conditions, treatment will be concentrated on the “A” roads with other roads in this category receiving treatment only when resources become available.

The adverse network (level 3) includes certain links to villages that are not on the precautionary network together with some bus routes and selected roads on industrial estates. When the precautionary routes do not require further (or continuous) treatment and resources allow, consideration will be given to treating roads on the adverse network when road surface temperatures are not expected to rise above freezing within a 48-hour period. However, consideration will also be given to pre-salting the adverse network prior to a high confidence forecast of snow or freezing rain settling on the network, with the decision at the discretion of the Programming and Network Operations Centre (NOC) Manager in consultation with North Northamptonshire Council.

On the remainder of the road network certain roads may be treated in prolonged adverse conditions if resources permit.

The treatment of persistent ice on road surfaces and snow clearance to prevent the accumulation of or to clear snow on the precautionary network will be carried out where conditions require.  In both cases priority will be given in accordance with the road hierarchy followed by providing at least one access from all those communities not on a precautionary treatment route to the precautionary network.

North Northamptonshire Council has a policy of promoting the use of grit bins by the public and will consider requests from town and parish councils for the provision of grit bins subject to the requested site satisfying certain criteria. The filling of North Northamptonshire Council maintained grit bins shall be the responsibility of the Highway Service Provider.

Precautionary treatment of footways is not carried out. In very severe weather, or prolonged cold periods especially where snow or ice may remain for several days, the treatment of some pedestrian routes in the priority of the footway hierarchy will be undertaken (see below). However, consideration will be given to pre-treating the priority 1 footways prior to a high confidence forecast of snow settling on the Network, with a decision at the discretion of the Programming and NOC Manager in consultation with the North Northamptonshire Council providing resources are available.

In order to minimise the adverse effects on the environment, the amount of de-icing agent used will be the minimum practicable, consistent with achieving adequate treatment.

Cross-boundary arrangements with West Northamptonshire Council and other highway authorities are the responsibility of North Northamptonshire Council and will be determined by them in accordance with Section 8 of the Highways Act 1980 and full co-operation will be given to adjoining highway authorities for cross boundary arrangements for precautionary treatment.

Any requests from Emergency Services for treatment of carriageways which are not on the gritting network will be assessed and only treated if it is an unnatural source (i.e. Water Leak, Seepage, etc)

Officer and service provider guidance

De-icing agents

  • The purchase and maintenance of stocks of de-icing agent shall be the responsibility of Kier who will also be responsible for ensuring that adequate levels are maintained in the operating depots to meet all treatment demands during the winter service period.  Kier will put in place arrangements with the supply chain to guarantee deliveries of de-icing agents before and during the winter service period
  • Kier will ensure that de-icing agent stocks are protected from the adverse effect of the weather
  • Rates of spread shall be adopted that will be the minimum that is practical to achieve adequate treatment while minimising the adverse effects on the environment

Grit bins

  • North Northamptonshire Council’s maintained grit bins will be filled with an appropriate amount of sand/salt on request via Street Doctor when resources permit
  • Permission for the provision of additional grit bins may be given by North Northamptonshire Council at locations subject to the following criteria:
  1. Must be on the public highway
  2. At sharp or difficult bends
  3. Junctions where the side road approach has a gradient
  4. On particularly steep gradients elsewhere (of 10% or greater)
  5. Community facilities
  6. Only access road to a community
  7. At known problem sites
  8. Not on roads which are included in the precautionary treatment network
  9. A grit bin will not be placed less than 150m from an existing bin
  •  All requests for new grit bins will be considered between May and October each year
  •  The condition of grit bins and the use of the grit will be recorded at the time of filling.  Where a grit bin requires replacement due to vandalism or general deterioration, its location will be assessed against the criteria detailed above before replacement. If the criteria are not met, the respective town or parish council will be consulted. Where there is evidence of limited use, consideration will be given, in consultation with the respective town or parish council, to relocate the grit bin to a more suitable location
  • Extra consideration will be given to the provision of a bin at a problem site on an industrial estate
  • Grit bins are provided for self-help by any member of the public and not by any nominated person
  • Kier is responsible for providing all new and replacement North Northamptonshire Council maintained grit bins and allocating a unique asset number to each bin for auditing purposes
  • Grit bins will have a 50/50 mix of sand and salt

Snow conditions

  • An Incident Response, Winter Operations and Severe Weather Management Plan, which includes details of subcontract plant and labour, will be prepared by Kier
  • To deal with deep accumulations of snow and to clear minor roads, arrangements will be made with local farmers and plant hire firms to call in loaders and other machines to supplement Kier resources as necessary
  • The declaration of snow conditions) will be by agreement with the Programming and NOC Manager in consultation with North Northamptonshire Council
  • In respect of cross-boundary arrangements with West Northamptonshire Council and adjoining highway authorities, treatment under snow conditions, adverse weather conditions or in response to Police requests following accidents will be carried out by the authority within whose area the treatment is required

Declaration of snow conditions - Definition

When the fleet is unable to keep pace with falling snow which results in the snow becoming heavily compacted by vehicular movements which are then unable to be ploughed or accumulations that are too deep for ploughing such as snow drifts caused by windy conditions.

Spreaders and loaders

Kier shall be responsible for the provision and maintenance of the gritter fleet including spare vehicles.

Depots

There is one dedicated Highways depot within North Northamptonshire and additional resources are available from a shared resource in West Northamptonshire:

  • Wellingborough Highways Depot
  • Brixworth Highways depot (additional resources)

Weather forecast and decision making

Kier shall:

  • Obtain a weather forecast for 24hrs / 36hrs and 8 days as well as a long-term forecast
  • Undertake all maintenance, updating, replacement, servicing, and the payment of all running costs associated with the Bureau system including weather stations
  • Make the decision on when to carry out treatment and the type of treatment required
  • Develop and implement a system to monitor treatment and snow clearing operations and weather forecasts. The system will also be capable of providing a 24-hour response to changes to weather forecasts and unpredicted events as well as providing situation updates to the media and motoring organisations
  • Retain detailed records of treatment operations, including weather forecasts, decisions, and operation reports for 21 years & 6 months for legal purposes

Cross boundary co-operation with adjoining highway authorities

  • Under the cross-boundary arrangements, made in accordance with Section 8 of the Highways Act 1980, precautionary treatment will be the decision of the treating authority
  • Treatment under snow conditions, adverse weather conditions or requests from the Police following accidents will be carried out by the authority within whose area the treatment is required

Performance

Performance is monitored through KPI 17.

Quality plan

Document control procedures

All information collated and recorded during the winter service period is filed electronically in the Winter Service files held by Kier.

The following information will be kept during the winter service season:

  • Copy of the Daily Weather Forecast from the forecast provider
  • Minutes of meetings in relation to winter service
  • Records of gritter operations
  • Copy of all gritting decisions throughout the winter season

Preparing for Winter

  • Checking the routes to ensure that they remain appropriate
  • Checking the calibration results for salt spreading equipment
  • Compiling the stand-by duty rotas
  • Ensuring the fleet is maintained and fit for purpose
  • Ensure operatives are trained and competent
  • Salt stocks maintained and sufficient to provide the service
  • Checking that grit bins are serviceable and filled with an appropriate amount of sand or salt
  • Procuring the weather forecasting / bureau service

Action during Winter

  • The decision-making process
  • Receive and assess weather forecasts
  • Response times and spread rate
  • Maintaining rotas
  • Managing severe weather events
  • Maintaining vehicles and salt levels
  • Monitoring contractor’s performance
  • Exactrak on-board route navigation and tracking
  • Checked safe on-line vehicle defect checking

Route planning

Kier as service provider for North Northamptonshire Council is responsible for the maintenance of 1,840.8km of highway. The courts have recognised that it is impossible for all roads to be salted or cleared; therefore, North Northamptonshire Council has adopted a reasoned policy to determine what will be treated.

The selection criteria for determining what sections of the network receive precautionary treatment are as follows:

  • Resilient Network (Except National Highways managed roads)
  • B and some C class roads
  • Roads carrying heavy commuter traffic
  • Roads linking centers of population
  • Roads that link to treated routes within adjacent authorities

Kier on behalf of North Northamptonshire Council also receive a route-based forecast (RBF) from the contracted forecast service provider which improves operational efficiency and reduces expenditure. Therefore, on marginal nights we can ascertain which areas require precautionary gritting, ensuring efficient use of resources.

The precautionary gritting routes within North Northamptonshire cover 44% of the carriageway network. This is broadly in line with similar authorities in both the East Anglian Consortium and the Midlands Service Improvement Group.

Despite the above there is 56% of the network which will remain untreated; we will inform the public of the service that the Council provides and give advice on precautions that they should take to ensure their safety.  

North Northamptonshire Council have divided the network into 3 categories:

  • Precautionary
  • Adverse
  • All other roads

Cross boundary arrangements

North Northamptonshire Council shares boundaries with West Northamptonshire Council and other Highway Authorities.  The general highway user is not aware of where these boundaries are located; therefore, it is important for all those responsible for providing a Winter Service to liaise in order to provide a consistently treated network. In addition, there are also operational advantages in term of improved efficiency in route planning.  Therefore, all Highway Authorities who have cross boundary arrangements with North Northamptonshire Council receive the operational decision daily during the winter season.

North Northamptonshire Council prior to each season consults with all neighbouring Highway Authorities to review the cross-boundary arrangements, where an exchange of letter constitutes an agreement in accordance with Section 8 of the Highways Act 1980 takes place.  All gritting operations carried out by that Authority in our area is undertaken according to their winter service policies and not that of North Northamptonshire Council.

North Northamptonshire Council share boundaries with the following authorities:

  • West Northamptonshire Council
  • Bedford Borough Council
  • Cambridgeshire County Council
  • Leicestershire County Council
  • Rutland County Council
  • Peterborough City Council

List of cross-boundary arrangements with adjoining counties and the routes which are covered:

Road Name

From and to

Authority

Treated By

Decision For Action

B645

CB to Junction of unclassified road (UC1) to Hargrave

Bedford Borough Council

North Northamptonshire Council

North Northamptonshire Council

C12 Class 3 road

Public House, Wymington (UC13) to County Boundary Wymington Road Rushden

Bedford Borough Council

North Northamptonshire Council

North Northamptonshire Council

A6

CB to Roundabout not including the southern end of Rushden By-pass

North Northamptonshire Council

Bedford Borough Council

Bedford Borough Council

C144/C72 Avenue Road, Rushden

A6 to County Boundary via Newton Bromswold

North Northamptonshire Council

Bedford Borough Council

Bedford Borough Council

Unclassified 13

CB Wymington Lane to A6

North Northamptonshire Council

Bedford Borough Council

Bedford Borough Council

Class 3 Lutton

CB to first crossroads in Cambridgeshire

Cambridgeshire County Council

North Northamptonshire Council

North Northamptonshire Council

B663

CB through Keystone to A14

Cambridgeshire County Council

North Northamptonshire Council

North Northamptonshire Council

A605 Warmington

CB to Warmington Roundabout

North Northamptonshire Council

Cambridgeshire County Council

Cambridgeshire County Council

B662

CB through Clipston to A605

North Northamptonshire Council

Cambridgeshire County Council

Cambridgeshire County Council

A508

CB to Market Harborough Leisure Centre

Leicestershire County Council

North Northamptonshire Council

North Northamptonshire Council

Class 3 East Farndon

CB to Welland Park Road, Market Harborough

Leicestershire County Council

North Northamptonshire Council

North Northamptonshire Council

Class 3 Sulby Airfield

CB to A5199

Leicestershire County Council

North Northamptonshire Council

North Northamptonshire Council

Station Road, Husbands Bosworth

A5199 to A4304

 

Leicestershire County Council

North Northamptonshire Council

North Northamptonshire Council

A5199 Welford

CB to A4304

Leicestershire County Council

North Northamptonshire Council

North Northamptonshire Council

Braybrooke Road, Scotland Road

CB to A508

Leicestershire County Council

North Northamptonshire Council

North Northamptonshire Council

A6

CB to A427

Leicestershire County Council

North Northamptonshire Council

North Northamptonshire Council

B670 Rockingham

Crossroads A6003 to Cottingham

North Northamptonshire Council

Leicestershire County Council

Leicestershire County Council

Unclassified Road Cottingham

Cottingham to County Boundary Bringhurst

North Northamptonshire Council

Leicestershire County Council

Leicestershire County Council

B664 Ashley

CB to Ashley Junction

North Northamptonshire Council

Leicestershire County Council

Leicestershire County Council

Class 3

County Boundary on road from Harringworth to B672

Rutland County Council

North Northamptonshire Council

North Northamptonshire Council

A43

CB to Northbound on slip A1

Peterborough City Council

North Northamptonshire Council

North Northamptonshire Council

A47

CB to Collyweston crossroads classified road to Kings Cliff

North Northamptonshire Council

Peterborough City Council

Peterborough City Council

Carriageway gritting routes

A map of the precautionary and adverse gritting routes is on the North Northamptonshire Council website.

Footways

The decision to treat Category 1 footways which are the responsibility of the Highway Authority will only be made by Programming and NOC Manager in agreement with North Northamptonshire Council and in accordance with the table below which states the policy.  Consideration will be given to pre-treating the priority 1 footways prior to a high confidence forecast of snow falling on the Network, with a decision at the discretion of the Programming and NOC Manager in consultation with North Northamptonshire Council providing resources are available.

Footway hierarchy

Winter service for footways and footway combined cycleways – treatment table:

Category

Overnight Frost Conditions

(Overnight forecast temperatures below zero but not extending beyond 8am)

Daytime Frost Conditions

(Forecast temperatures below zero)

Extended Ice Conditions

(Persistent widespread ice (rather than frost) for more than 18 hours in a 24 hour period and a forecast not to rise above zero for a further 18 hours in the next 24 hours)

Snow Events

1a

No treatment

Precautionary treatment

Monitor and further treatment as required when resources permit. Treatment will generally be during normal working hours.

Snow removal will commence when resources come available from higher priority treatments. Endeavours will be made to complete clearance within 12 hours of cessation of snowfall, subject to availability of resources. Treatment will generally be during normal working hours.

1

No treatment

No treatment

Monitor and treatment as required when resources permit. Treatment will generally be during normal working hours.

Snow removal will commence when resources come available from higher priority treatments. Endeavours will be made to commence clearance within 24 hours of cessation of snowfall, subject to availability of resources. Treatment will generally be during normal working hours.

2

No treatment

No treatment

Monitor and treatment as required when resources permit. Treatment will generally be during normal working hours.

Snow removal will commence when resources come available from higher priority treatments. Endeavours will be made to commence clearance within 48 hours of cessation of snowfall, subject to availability of resources. Treatment will generally be during normal working hours.

3 and 4

No treatment

No treatment

Reactive treatment not normally undertaken other than in response to specific circumstances. Treatment will generally be during normal working hours.

Snow removal will commence when resources come available from higher priority treatments. Endeavours will be made to commence clearance within 5 days of cessation of snowfall, subject to availability of resources. Treatment will generally be during normal working hours.

At all times priority will be given to the precautionary road gritting network, footways will be treated when resources are available, and the precautionary network requires no further treatment.

Combined footway and cycleways are treated in accordance with footway hierarchy.

Segregated cycle ways are not treated.

 

Weather prediction and information

Provision of forecasting services

North Northamptonshire Council and Kier are members of the East Anglian Consortium for Weather Forecast Services. The purpose of the consortium is to maximise the benefits gained through the joint procurements of Weather Forecasting Services; however, membership of the consortium has led to further co-operation in other areas.

The services provided through this contract include the following:

Standard Winter Service:

  • 36 hour forecast
  • 8 day general forecast
  • Statistical Analysis

Site Specific Services:

  • Site Specific Forecast
  • 24 hour Forecast Thermal Map
  • Late afternoon/evening update

Additional Services:

  • 24 hour consultancy service
  • 24 hour system monitoring service
  • Route based forecast

Service

Delivery Time

36 Hour Forecast

Between 12 noon and 1pm

8 Day Forecast

Between 12 noon and 1pm

Routine Update

Between 6pm and 7pm

Consultancy

As required

Site specific forecasts will be made available for the following weather stations in North Northamptonshire:

  • B576 Rothwell
  • A509 Hill Top Harrowden
  • A427 Upper Benefield
  • Nassington

Weather station systems

North Northamptonshire Council operates four weather stations. In addition to these weather stations, decision makers can access information from several other stations operated by neighbouring authorities.

The purpose of these devices is to provide accurate specific information relating to weather and road conditions at the location of these stations.

The Road Surface Analyser (ROSA) weather stations are maintained regularly

  • Out station servicing
  • Provision of workstation software
  • Workstation servicing (including software support)
  • Bureau service

The bureau is a management system that controls the flow of information between weather stations, forecasters and clients.

Any failure of the weather station will be identified by the bureau provider but Kier can detect that data is not being downloaded at the normal frequencies and alert the bureau provider.

Decision process

The Winter Duty Manager (WDM) in agreement with the Duty Manager (DM) will be responsible for the decision making in respect of the Winter Service operations. If the WDM/DM are unable to agree on a decision the WDM will contact a senior member of the Severe Weather Team for advice and guidance on making the final decision.

The forecast will always be checked at 8am, 12 noon, 6pm and 11pm, further checking will be required when temperatures are between +0.5c and +4.0c (see table below).

TemperatureAction

+0.5c and below

Gritting required refer to section 8.1. Red forecast.

+0.5c to +2.0c

Likelihood of a gritting action being required, forecasts to be monitored hourly until decision can be confirmed. All changes to the gritting action to be re-communicated by email and text and Twitter. Amber forecast.

+2.0c to +4.0c

Decreased likelihood of a gritting action being required, forecasts to be monitored bi-hourly until decision can be confirmed. All changes to the gritting action to be re-communicated by email and text and Twitter.

Above +4.0c

No gritting action required.

All drivers on a red or amber forecast will be required to stand down to adhere to the Drivers Hours rules if a gritting action is planned or is likely. Drivers on a blue or green forecast do not need to be stood down at this time.

If the forecast changes, the decision needs to be reviewed. If it is perceived that further actions or less actions are required on the precautionary network to provide assurance that we are complying with the plan the decision of the applied changes must be communicated via text, email and Twitter to the contact groups. Systems and documentation must also be updated to show the changes.

Route based treatment

If all routes are red within the forecast period, with similar timings and severity of hazards then a full precautionary gritting action must be implemented.

Route based treatments will be implemented if the following trigger points are met:

  1. Less than 75% of routes are showing a red forecast with hazards (planned precautionary treatment on these routes and all amber routes)
  2. Timings of hazards should be considered, fog, rain, hoar frost, ice, freezing rain, traffic conditions. This information would then show if there are any different timings of treatments to be implemented.
  3. Spread rates are to be applied as required (see below) to each individual route.

However, if there is only a single gritting route to go from a depot, lone working needs to be considered and communication maintained with that driver at all times.

Cancellation of gritting actions:

Cancellation of gritting action due to change in forecast

Payment to drivers

More than 2 hours before gritting action

No payment to drivers

Between 30 minutes and 2 hours before gritting action

3 hours pay

Less than 30 minutes before gritting action (gritting action deferred until after shift change).

3.5 hours pay or full payment for the time in the depot (including 30 minutes pre-gritting period).

Stand-down times may still apply to cancelled or postponed gritting actions.

During normal working hours, defined as Monday to Friday, 8am to 5pm, the Severe Weather team will obtain forecasts and make treatment decisions, the WDM will monitor the weather forecasts outside of these hours and will decide if there needs to be a change of response, and action as necessary.

A 36-hour forecast with an extended outlook for 5 days will be received each day by 12:30pm and with an evening update received by 6pm.  Further updates will be obtained outside of these periods.  

The Severe Weather Team and WDM will ensure the decision is made following the lunchtime forecast with the information sent to relevant bodies by 1pm.

  • +4c and above – No action
  • below +4c – WDM/DM to monitor electronically throughout the forecast period

Notification of the decision will be passed on to all relevant parties via text, email, and Twitter. 

The WDM will consider the information available to them, including the actions of neighbouring authorities and agencies, and base the decision on the recommendations within Tables H2 and H4 of the Code of Practice, which is detailed in this section.

Only the agreed network should be treated unless in extreme circumstances and following liaison if required with emergency services. For example, ice forming in an unusual location as a result of a water leak. The precautionary network is noted above.

If conditions dictate, the Severe Weather Manager will set up 24 hour operations. Two teams will be employed on 12 hour shift on the approval of the duty severe weather lead.

Salt spread rates

The guidance available to local authority practitioners to assist them in preparing their winter service plans is available in Section B7 of the Well-Managed Highway Infrastructure which sets out the broad context and framework for the winter service, while the National Winter Service Research Group (NWSRG) practical guidance documents provides details about treatment decisions.

Treatments and monitoring

This section describes the treatment considered in this guidance, the reasoning used to determine spread rates and the monitoring required to check their effectiveness.

Precautionary treatments

These are the application of de-icers to road surfaces before the onset of freezing conditions (i.e. frost, snow or freezing rain).  The purpose of precautionary treatments is to prevent the formation of ice, or to weaken or prevent the bond of freezing rain or snow to road surfaces.

It is usually impractical to spread sufficient salt to melt freezing rain or more than a few millimetres of snow. Therefore, in advance of forecast snow or freezing rain, salt is spread to provide a de-bonding layer so that:

  •    snow is more readily removed by ploughing
  •    compacted snow and ice are more easily dispersed by traffic

It is very difficult to remove a layer of compacted snow or ice that is bonded to the road surface, so precautionary treatments are essential before heavy snowfall.

Spread rates for precautionary treatments

Most winter service treatments (and salt spread) in the UK are precautionary treatments in response to predicted frost conditions.  In these, commonly marginal conditions, significant salt savings can be achieved using the rates given in this guidance when using salt which has been stored in good conditions and using good equipment which has been properly calibrated.  The use of treated salt can also provide salt savings compared to dry salting.

For precautionary treatments when frost conditions are forecast, this guidance gives a table of recommended spread rates. The appropriate rates to use depend upon the spreading capability, which in turn depends on the condition of the salt, spreader performance and calibration.  The lower spread rates are used where the spreading capability is deemed to be ‘reasonable’, and the higher rates are used where the capability is ‘modest’.

Post treatments

Post treatments involve the ploughing of snow, the application of de-icers and the application of abrasives to ice and snow present on the road surface, or some combination of these.

Although de-icers will melt ice or snow directly, it is normally impractical to apply enough de-icer to melt a moderately thick ice or snow layer.

Ploughing is the only economical, efficient, effective and environmentally acceptable way to deal with all but very light snow.

Monitoring

The condition of routes should be monitored following treatment in order to confirm that the treatment has been effective.  If it has not been fully effective, contingency treatments should be considered to achieve the required condition.  It should be noted that both active and passive road weather sensor systems require the presence of moisture to determine either the concentration of an anti-icing chemical on the road or the freezing point temperature of the solution present on the road sensor.

Decision making process

A suggested procedure for decision making, taking into account various operational scenarios is provided in this section. This procedure may be modified as necessary to suit local circumstances and winter service plans.

The training of decision-makers and managers is important. Although there is no formal qualification currently available for Winter Service decision making and management, such staff should have several years’ experience and have received a sufficient level of training in operational and weather forecasting methods through the Weather Service Provider.

Road surface wetness

For the purpose of allocating treatments, a distinction is made between dry, damp and wet road surfaces. The following definitions should be used when making the treatment decision:

Road surface wetness

Definition

Dry road

A road that shows no signs of water or dampness at the surface but may be just detectably darker. However, it may have moisture contained in pores below the surface that is not ‘pumped’ to the surface by traffic.

Damp road

A road which is clearly dark, but traffic does not generate any spray.  This would be typical of a well-drained road when there has been no rainfall after 6 hours before the treatment time.

Wet road

A road on which traffic produces spray but not small water droplets.  This would be typical of a well-drained road when there has been rainfall up to 3 hours before the treatment time

Very wet road and flowing water on road

A road on which traffic produces droplets of water in the air to visibly flowing water on the surface

The amount of salt required to prevent ice forming in these conditions is considered impractical for authorities to deliver during normal precautionary salting operations.

Traffic levels

For the purpose of allocating treatments, the guidance defines four levels of trafficking on the road – Light, Medium, High and Congested.

Level

Vehicles per lane per hour

Light

Less than 20

Medium

20 to 250

High

250 or more and moving at normal traffic speeds

Congested

250 or more moving slower than normal traffic speeds

Precautionary treatment decision matrix

A decision matrix for precautionary treatments based on road surface conditions and predicted weather conditions:

Road surface temperature

Precipitation

Road condition - Wet

Road condition - Wet patches

Road condition - Dry

Above 0.5°C

No rain, hoar frost or fog

No action

(see decision process above)

No action

(see decision process above)

No action

(see decision process above)

May fall below 0.5°C

No rain, hoar frost or fog

Salt before frost

(see decision process above)

Salt before frost (see note a)

(see decision process above)

No action likely, monitor weather (see note a)

(see decision process above)

Expected to fall below 0.5⁰C

No rain, hoar frost or fog

Salt before frost

(see decision process above)

Salt before frost (see note a)

(see decision process above)

Salt before frost (see note a)

(see decision process above)

Expected to fall below 0.5⁰C

Expected hoar frost or fog

Salt before frost

Salt before frost (see note b)

Salt before frost (see note b)

Expected to fall below 0.5⁰C

Expected rain before freezing

Salt after rain stops (see note c)

Salt after rain stops

 (see note c)

Salt after rain stops (see note c)

Expected to fall below 0.5⁰C

Expected rain during freezing

Salt before frost, as required during rain and again after rain stops (see note d)

Salt before frost, as required during rain and again after rain stops (see note d)

Salt before frost, as required during rain and again after rain stops (see note d)

Expected to fall below 0.5⁰C

Possible rain, hoar frost or fog

Salt before frost

Salt before frost

Monitor weather conditions

Not applicable

Snow fall expected

Salt before snow fall

Salt before snow fall

Salt before snow fall

The decision to undertake precautionary treatment should be, if appropriate, adjusted to take account of residual salt or surface moisture.

All decisions should be evidence based, recorded and require continuous monitoring and review.

(a) Particular attention should be given to the possibility of water running across carriageways and other running surfaces e.g. off adjacent fields after heavy rains, washing off salt previously deposited. Such locations should be closely monitored and may require treating in the evening and morning and possibly on other occasions.

(b) When a weather warning contains reference to expected hoar frost, considerable deposits of frost are likely to occur. Hoar frost usually occurs in the early morning and is difficult to cater for because of the probability that any salt deposited on a dry road too soon before its onset, may be dispersed before it can become effective. Close monitoring is required under this forecast which should ideally be treated just as the hoar frost is forming. Such action is usually not practicable, and salt may have to be deposited on a dry road prior to and as close as possible to the expected time of the condition. Hoar frost may be forecast at other times in which case the timing of salting operations should be adjusted accordingly.

(c) If, under these conditions (see above Precautionary Treatment Decision Matrix table), rain has not ceased by early morning, crews should be called out and action initiated as rain ceases.

(d) Under these circumstances (See above Precautionary Treatment Decision Matrix table), rain will freeze on contact with surfaces and full pre-treatment should be provided even on dry roads. This is a most serious condition and should be monitored closely and continuously throughout the danger period.

(e) Weather warnings are often qualified by altitudes in which case differing action may be required from each depot.

(f) Where there is any hint of moisture being present, a pessimistic view of the weather forecast should be taken when considering treatment to negatively textured surfaces.

Spread rates for precautionary treatments

The spread rates are from the National Winter Service Research Group (NWSRG) guidance for winter service.

Target spread rates of salt for precautionary treatments

Spread rates for precautionary treatment (forecast frost conditions).

Spread rates for precautionary treatments before frost are given in the National Winter Service Research Group (NWSRG) practical guidance for winter services spread rates.  The tables provide recommended spread rates for treated salting for a range of weather and road surface conditions, Kier will be using treated salt.

The following points must be considered when using the spread rate tables:

  1. The given spread rates are for sections of well drained roads without ponding or runoff from adjacent areas.
  2. The rates may be adjusted to take account of variations occurring along routes such as temperature, surface moisture, road alignment and traffic density.
  3. The rates may be adjusted to take account of residual salt levels.  However, residual salt levels will tend to be lower if lowered spread rates are introduced.  Residual salt levels are most likely to be significant on marginal nights after treatments on two or three successive days without precipitation in the intervening period.
  4.  On porous asphalt and on dense surfacing for 1km after a change from porous asphalt, spread rates should be increased by 50% on roads with medium traffic levels and by 25% on heavily trafficked roads.
  5. Spread rates should be increased to a rate appropriate for the particular situation where negatively textured thin surfacing is poorly drained such that water can accumulate within the surface texture.
  6. All decisions should be evidence based, recorded and require appropriate monitoring and review.
  7. During periods of sustained freezing and if surfaces are well drained and there is neither seepage (from melt water) nor ice present, rates of spread for treatments carried out within six hours of previous treatments may be 50% of the rates stated in the appropriate table.

The spread rates are from the recommendations of the NWSRG Treatment Matrix 8.6.8.

The matrix below provides recommended spread rates for precautionary treated salting operations on local authority roads in response to predictions of ice and frost formation.

Treated salt incorporates an additive to improve performance, as well as reducing the rate of salt loss after spreading.

Recommended Spread Rates – Treated Salt (g/m²)

 

Road Surface Temperature (RST) when frost or ice is predicted

Spreader capability is fair and dry or damp Road

Spreader capability is fair and

wet road

Spreader capability is good and dry or damp road

Spreader capability is good and wet Road

At or above -1.0c

7

7

7

7

-1.1c to -2.0c

7

8

7

7

-2.1c to -3.0c

7

12

7

10

-3.1c to -4.0c

9

17

7

13

-4.1c to -5.0c

11

21

8

16

-5.1c to -7.0c

15

29

11

22

-7.1c to -10.0c

May require multiple treatments to ensure sufficient de-icing material is present on the road surface

20

40

16

31

-10.1c to -15.0c

May require multiple treatments to ensure sufficient de-icing material is present on the road surface

26

55

22

43

Organisational arrangements and personnel

Kier structure for winter service

  • Operations Manager
  • NOC Manager reports into Operations Manager
  • Communications Team reports into Operations Manager and NOC Manager
  • Severe Weather and Response Supervisor reports into NOC Manager
  • NOC Centre reports into Severe Weather and Response Supervisor
  • Emergency Response Attenders report into NOC Centre
  • Duty Managers report into NOC Centre and work with Winter Duty Manager Managers
  • Winter Duty Managers report into Severe Weather and Response Supervisor and work with Duty Managers
  • Gritter Drivers and Supply Chain Partners report into Winter Duty Managers

Winter Duty Staff (WDS)

Throughout the Winter Service Period (15 October to 15 April) the WDS will be responsible for all aspects of the winter service.

Emergency contacts:

ContactTelephone

Street Doctor (Monday to Friday, 9am to 5pm)

0300 126 3000

Duty Manager (outside of above hours)

01604 651074

Winter Duty Manager (outside of above hours)

08700 781245

All WDS will be identified, as being competent to carry the duties required.  This competency will be achieved by:

  • training
  • mentoring
  • supervised experience
  • continued monitoring of performance

Training and monitoring records of the WDS involved will be maintained by the Training Coordinator.

WDS will have access to the following:

  • Sufficient Training, both initial and continued development
  • Access to the Winter Service Plan
  • Access to the Incident Response, Winter Operations and Severe Weather Management Plan
  • Access to NWSRG Practical Guidance Documents
  • Access to the weather forecasts for road conditions within North Northamptonshire
  • Weather forecasting consultancy support
  • Actions taken by neighbouring authorities who share cross boundary arrangements
  • Previous instructions relating to actions taken

North Northamptonshire Council officer responsible for Winter Service

  • Assistant Director – Highways and Waste

Salt and other de-icing materials

North Northamptonshire Council has adopted 6.3 mm Thawrox+ as its principal de-icing agent.

Thawrox+ contains Rock Salt with the addition of an agricultural co-product of a molasses type. Rock Salt is approximately 94% pure salt and has a characteristic reddish-brown colour owing to the presence of marl (an insoluble mineral) which is the chief impurity. The presence of molasses deepens this colour.

Thawrox+ is an enhanced form of BS3247 rock salt that has been pre-mixed with an agricultural by-product (ABP). Added at a minimum of 2.5% by weight, ABPs have been shown to enhance the spreading characteristics of rock salt and improve adhesion to the road surface. Thawrox+ possesses powerful anti-icing and de-icing properties while offering reduced corrosion compared to standard rock salt.

Chemical specification

Test methods are as specified in BS3247:2011 Salt for spreading on Highways for Winter Service, except for ‘ABP additive’ which is tested during manufacture. A spectrophotometric method which can provide indicative additive levels in the finished product is available on request.

Property

Unit

Specification

Typical analysis

Soluble Chlorides

% m/m NaCl

>87.0

91.0

Soluble Sulphate

% m/m CaSO4

<2.5

1.6

Insolubles

% m/m

<8.0

5.4

Moisture

% m/m

<4.0

1.86

Anti-caking agent

mg/kg

>30

55

ABP Additive

% m/m

Min 2.5

3.0

Grading as 6mm Product

Passing BS 410 test sieve

Specification % m/m

Typical analysis

10 mm

100

100

6.3 mm

100

100

2.36 mm

30-80

55

0.3 mm

<20

3

Bulk density

Delivered product has a bulk density of approximately 1200 kg/m³.

The effectiveness of the above salt is that it will melt snow and ice to -21⁰C but below -5⁰C its effectiveness is reduced and below -10⁰C the quantity required to be effective is environmentally and economically undesirable.

The Thawrox+ salt is stored under cover at Wellingborough and Brixworth depots.,

The amount of salt at the depots is as follows

  • Brixworth – 2,000 Tonnes
  • Wellingborough – 2,500 Tonnes

A loading shovel will be provided at each of the depots.

Stock management system will maintain the amount of salt in each depot

Testing of the salt will be carried out if/when required by either North Northamptonshire Council or Kier.

Grit bins

The condition of grit bins and the use of salt will be recorded at the time of filling. Where grit bins require replacement due to vandalism or general deterioration, its location will be assessed against the current criteria before replacement. If the criteria are not met, the respective town or parish council will be consulted.  Where there is evidence of limited use, consideration will be given, in consultation with the respective town or parish council, to relocate the grit bin to a more suitable location.

Extra consideration will be given to the provision of a bin at a problem site on an industrial site.

Grit bins are provided for self-help by any member of the public and not by any nominated person.

Kier is responsible for providing all new and replacement grit bins.

The number of grit bins in North Northamptonshire as of 11 August 2022 are:

  • Corby area - 53
  • East Northamptonshire area - 206
  • Kettering area - 198
  • Wellingborough area - 186
  • Total in North Northamptonshire - 643

Information and publicity

Publicity is continued throughout the season to ensure a consistent and clear message is given and that the public know where to find the very latest information.

Local press and broadcast contact information

Kier will communicate with the media to ensure consistent and complete coverage of our service.

In severe weather conditions Kier’s Customer Service Excellence Manager and the Duty Severe Weather Lead will communicate with North Northamptonshire Council’s communication team to give greater resilience within North Northamptonshire.

Other key local and national contact information

Contact details for public transport operators and emergency services are stored and used to keep lines of communication open.

In addition, Kier will utilise VMS to inform the travelling public of potential hazards on the highway network as well as publishing the daily decisions on Twitter.

Snow conditions

Treatments for snow and ice: The guidance below is taken from the section nine of the NWSRG section nine – Treatment for snow and ice.

General

  • It is impractical to spread sufficient salt to melt anything other than very thin layers of snow and ice
  • Ploughing is the only economical, efficient, effective and environmentally acceptable way to deal with all but very light snow
  • Ploughing down to the road surface is preferred. However, snow ploughs should be set to avoid risk of damage to the plough, the road surface, street furniture and level crossings
  • Ploughing to the road surface minimises salt usage and makes salt treatments more effective
  • Drainage should not be obstructed when ploughing. Windrows or piles of snow should be removed or be positioned to allow melt water to reach the drains. If necessary, piles of snow should be removed so that melted snow does not overload drainage systems or run back onto the road
  • Windrows should be removed or ploughed back when further periods of heavy snow are anticipated. This will provide space to plough further snowfalls

Preparation before ice and snow

To prepare for and facilitate ice and snow treatments the following should be considered:

  • When snow is forecast, ploughs and snow blowers should be prepared and positioned in order that snow clearance can start without delay as and when required
  • To facilitate the breakup and dispersal of ice and snow by trafficking, treatments must be made before snowfall or freezing rain so that sufficient de-icers are present on the surface to provide a debonding layer
  • Although it will increase salt usage, before snowfall and where practicable, consideration should be given to spreading salt on as much of the network as possible (i.e. beyond the normal precautionary salting network).  This will provide a debonding layer and facilitate the breakup and dispersal of snow by traffic in areas where subsequent treatments may not take place for some considerable time or at all

Depths of snow (light snow, moderate to heavy snow)

This guidance defines two main snowfall categories – light snow and moderate/heavy snow.

The highest practicable spread rates are considered to be 40g/m2 of dry salt.  When combined with the action of traffic, this is sufficient de-icer to melt snow depths which are equivalent to 1mm of water at temperatures down to -2⁰C. Generally, there is approximately 1mm of water in 5mm depth of wet snow, 10mm depth of ‘normal’ snow and 15mm depth of dry, powdery snow.

In this guidance, ‘light’ snow is taken to be snow equivalent to 1mm of water (or less) while snowfalls equivalent to more than 1mm are considered to be moderate heavy, as shown in the table below:

Depth of snow (mm)

Wet snow

Normal snow

Dry snow

0 to 5

Light snow (equivalent to up to 1mm of water)

Light snow (equivalent to up to 1mm of water)

Light snow (equivalent to up to 1mm of water)

5 to 10

Moderate or heavy snow

(equivalent to more than 1mm of water)

Light snow (equivalent to up to 1mm of water)

Light snow (equivalent to up to 1mm of water)

10 to 15

Moderate or heavy snow

(equivalent to more than 1mm of water)

Moderate or heavy snow

(equivalent to more than 1mm of water)

Light snow (equivalent to up to 1mm of water)

15 to 20

Moderate or heavy snow

(equivalent to more than 1mm of water)

Moderate or heavy snow

(equivalent to more than 1mm of water)

Moderate or heavy snow

(equivalent to more than 1mm of water)

20 to 25+

Moderate or heavy snow

(equivalent to more than 1mm of water)

Moderate or heavy snow

(equivalent to more than 1mm of water)

Moderate or heavy snow

(equivalent to more than 1mm of water)

Precautionary treatments before snow or freezing rain

The spread rates are from the recommendations of the National Winter Service Research Group (NWSRG) Treatment Matrix 9.8.5.

Treatments Before Snow or Freezing Rain

Weather conditions

Spread rates

Light to moderate or heavy snow forecast

15 to 30g/m² of treated salt

Freezing rain forecast

30 or 2x15g/m² of treated salt

In situations where time constraints dictate, a treatment of 15g/m² across the whole of the scheduled network before the commencement of snowfall or freezing rain will typically prove more advantageous than a treatment of 30g/m² on only part of the network.

Treatments during snowfall

Treatments during snow and freezing rain

The treatments are from the recommendations of the National Winter Service Research Group (NWSRG) Treatment Matrix 9.9.1

  • Plough to remove as much material as possible (e.g. slush, snow, compacted snow)
  • Ploughing should be down to the level of the road surface
  • Ploughing should start and where necessary be continuous to prevent a build-up of snow
  • As snow melts under the action of salt, keep ploughing to remove slush
Ice and snow

No ice or compacted snow on surface

Ice or compacted snow on surface

Traffic likely to compact subsequent snowfall before further ploughing is possible

Ice or compacted snow on surface

Traffic not likely to compact subsequent snowfall before further ploughing is possible

Treatment

To provide a debonding layer, spread:

15-30g/m2 of Treated salt

To provide a debonding layer, spread:

15g-30g/m2 of treated salt

No de-icer should be spread

A de-icer should not be spread alone without abrasives to other than a thin layer of ice or compacted snow when snowfall has ceased or future snowfall will be less than 10mm.

Applying salt alone to compacted snow and ice can produce dangerously slippery conditions if a weak brine film is formed on top of the ice or snow layer.

Treatment for thin layers of ice (less than 1mm thick)

The treatments are from the recommendations of the National Winter Service Research Group (NWSRG) Treatment Matrix 9.10.4.

Forecast weather and road surface conditions

Spread rates

  • Lower of air or road surface temperature
  • Above -5°C
  • 40g/m² of treated salt
    or
  • 40g/m² of salt/abrasive mix
  • Lower of air or road surface temperature
  • At or below -5°C
  • 40g/m² of salt/abrasive mix (50:50)

For best performance abrasives should ideally be 5 to 6mm and angular. Salt and abrasive should be pre-mixed before loading onto the spreader, The mix proportions should be approximately 50:50 by weight.

Care is needed when salt is mixed with abrasives with high moisture content.  Checks should be made that the mixture remains free flowing, does not clump and can be spread effectively.

After abrasives have been used, drainage systems should be checked and cleared if necessary. Recovered material, which will be contaminated with road oil, must be disposed of safely. 

Treatment of compacted layers of snow and ice

The treatments are from the recommendations of the National Winter Service Research Group (NWSRG) Treatment Matrix 9.11.3

Plough to remove as much material (e.g. slush, snow, compacted snow) as possible from the top of the compacted layer.

Snow and ice thickness

Medium layer thickness (1 to 5 mm)

High layer thickness (greater than 5mm)

Treatment
  • For initial treatment, spread 40g/m2 of salt and abrasive mix (50:50)
  • For successive treatments, spread 20g/m2 of salt and abrasive mix (50:50)
  • For initial treatment, spread 40g/m2 of abrasives only
  • For successive treatments, spread 20g/m2 of abrasives only
  • After traffic has started breaking up the layer spread 20g/m2 of salt/abrasive mix (50:50) so salt can penetrate the layer and reach the road surface

For compacted snow, when no further snow is expected, salt and abrasive mixtures or abrasives are applied to assist the action of traffic in breaking the layer. When further snow is expected, salt and abrasive mixture treatments may be applied to provide grip as well as a debonding layer between the existing layer and any future snow to assist future ploughing operations.

Salt should not be applied on its own as it may eventually form a weak brine solution which may re-freeze to form an ice or ice and brine layer.

Snow conditions – carriageway

Clearance of carriageways will be in stages as follows:

Stage 1

Roads will be dealt with on a priority basis, starting with the heaviest trafficked priority network routes. 

Clearance of Precautionary A routes will be carried out by Kier.

The clearance of locations where a particular problem is identified will be carried out by Kier with possible assistance from hired plant.

When a reported blockage on precautionary A route or other locations has been confirmed by Patrols, this will be then cleared by hired plant under Kier supervision. The contractor/hired plant to be used will be directed to a location closest to their base. These routes will be treated by Kier with salt or salt/abrasive mix as soon as possible after they have been made passable.

Operators of suitable plant that can be used for emergency snow clearing will be asked for a quotation to obtain prices for the different types of plant available at the start of each winter season.

Schedules of local plant hire operators for emergency snow clearing will be prepared at the start of each season. The aim is to give plant operators roads to clear as close to their base as possible. Location of blockages in priority order will be given at first contact with instructions to contact the Duty team as each location is cleared.

Operators will not start the clearance of snow without authority from Kier Duty team.

Stage 2

If snow conditions continue the remainder of the network should only be cleared if the general outlook for the next 48 hours indicates that roads are likely to remain impassable. All remaining available plant operators will be contacted and instructed which route to cover but must not go without prior instruction from Kier.

The decision to continue to Stage 2 will be made by Kier in agreement with North Northamptonshire Council.

Snow condition – footways

Footways of high usage, including town centers footways as shown in the footway hierarchy will be treated first but when the snow conditions are prolonged other footways may be dealt with.

Treatment will take place in the following stages:

Stage 1

Snow clearance and salting

In main areas where there is high pedestrian usage (i.e. main shopping areas). Programming and NOC Manager in agreement with North Northamptonshire Council will decide that work will commence.

North Northamptonshire Council will keep Kier informed of locations to be treated.

Stage 2       

If snow conditions continue salting but with snow clearance and salting at localised problem areas such as in the region of high usage entrances or crossings.

  1. Adjacent to heavily trafficked roads where the footway has a high pedestrian usage and pedestrians may otherwise walk in the road
  2. Outside hospitals, schools and similar locations where there are heavy concentrations of pedestrians
  3. At locations where there is an above average usage by the elderly and infirm
  4. On particularly steep gradients

Stage 3

Salting only, on footways which are not scheduled for treatment and are not served by grit bins for which, in the prevailing conditions justifiable requests for service are received.

Stage 3 is only to be treated if the general outlook indicates that conditions will continue for the foreseeable future.

Severe weather conditions

Salt stocks

Salt stocks at the start of the season will be 4,500 tonnes. Orders will be placed to replenish stocks at the agreed minimum salt level.

Total capacity should allow for approximately 54 Salting Operations on Precautionary routes for a spread rate of (12g/m²). 

Vehicles and plant

Hired plant will be available to assist with the clearance of snow.

Additional drivers

The number of drivers will be maintained to provide coverage of the agreed routes. The drivers will be fully trained and qualified to NVQ standard throughout the season.

Fuel stocks and provision

There are two 10,000 litres tanks, one each located at Wellingborough and Brixworth depots and reordering of stocks will take place when approximately 2,000 litres has been used at each depot.

Each depot also stocks 1,000 litres of Adblue, which is re-stocked when approximately 500 litres have been used at each depot.

All vehicles should start each day with full tanks as far as is possible.

Non-standard declarations of snow conditions

Kier will initiate the consultation with the North Northamptonshire Council Nominated Deputy should any decision other than the standard declaration of snow conditions be required and the Emergency Planning Office will be kept informed by the Severe Weather Lead.

Post snow inspections and maintenance

Following snow clearance operations, a special inspection will be carried out by the Safety Inspectors based on the road hierarchy and will deal with items that are usually included in a standard safety inspection.

A debriefing session will be held with all personnel involved to ensure their observations are recorded and contribute to the process of continuous improvement.

Last updated 16 October 2023