Module 5: Winter Maintenance
1. Gritting and Snow Clearance Procedures
A. Pre-Treatment (Precautionary Gritting):
Timing: Applied before frost/ice forms (typically 2-4 hours before predicted freezing).
Coverage:
Priority routes (A-roads, bus lanes, emergency routes) treated first.
Standard spread rate: 10-20g/m² (varies by forecast severity).
Techniques:
Dry Salting: Rock salt spread on dry roads for frost prevention.
Wet Salting: Brine solution (23% salinity) for better adhesion in light snow.
B. Snow Clearance:
Ploughing:
Primary routes cleared first (snowploughs with adjustable blades).
"V-Ploughs" for heavy accumulations (>50mm).
Snow Blowers: Used for deep snow in rural/car park areas.
Post-Snow Treatment:
Re-gritting to prevent re-freezing of meltwater.
Clearance of snow piles to maintain drainage.
C. Pedestrian Areas:
Footpaths & Cycleways: Smaller ploughs or brush attachments.
Manual Clearing: Shovels for steps/sensitive areas (e.g., hospital entrances).
2. Use of Salt and De-Icing Agents
A. Types of De-Icers:
B. Environmental Considerations:
Salt Damage Mitigation:
Avoid over-application near trees/sensitive ecosystems.
Use geotextile-lined salt piles to prevent groundwater contamination.
Alternative Treatments:
Grit/Sand: Improves traction but does not melt ice.
Beet Juice Molasses: Mixed with brine to reduce salt usage.
3. Winter Maintenance Vehicles and Equipment
A. Fleet Requirements:
Gritters:
Spreaders: Tailgate or spinner mechanisms (calibrated for even distribution).
Pre-Wet Systems: Spray brine onto salt as it’s spread (reduces bounce/scatter).
Snowploughs:
Front-Mounted: For primary routes (e.g., A-roads).
Underbody Blades: For secondary roads with lighter snow.
Support Vehicles:
4x4 Tractors: For rural/pavement clearing.
Quad Bikes: For narrow paths or pedestrian zones.
B. Equipment Checks:
Pre-Winter Readiness:
Calibrate spreaders (ensure 10-40g/m² accuracy).
Anti-icing nozzles tested for blockages.
Daily Maintenance:
Wash down vehicles to prevent corrosion.
Check tyre chains/blade sharpness.
4. Monitoring Weather Conditions and Response Planning
A. Forecasting Tools:
Road Weather Stations (RWS): Measure:
Pavement temperature.
Air humidity (predicts black ice risk).
Thermal Mapping: Identifies cold spots (e.g., bridges, shaded areas).
B. Decision-Making Process:
Alert Levels:
Amber (Precautionary): Gritting likely within 24hrs.
Red (Imminent): Gritting crews on standby.
Treatment Triggers:
Frost/Ice: When pavement temps drop below +0.5°C.
Snow: Activated at 1cm+ accumulation forecast.
Resource Allocation:
Day/Night Shifts: 24/7 coverage during severe weather.
Contractor Backup: For extended cold spells.
C. Communication Protocols:
Public Updates:
Real-time gritter tracking (council websites/apps).
Social media alerts for school/business closures.
Internal Coordination:
Highway Control Centres monitor gritter GPS.
Police liaison for emergency route access.
Key Takeaways
Proactive Gritting: Prevents ice bonding to pavement.
Right Material: Rock salt for cost-efficiency; MgCl₂ for extreme cold.
Tech Integration: Thermal mapping + RWS optimizes resource use.
Safety First: PPE for crews (gloves, anti-slip boots, high-vis).
Practical Training:
Simulation Exercise: Use weather data to plan a gritting run.
Equipment Demo: Hands-on spreader calibration practice.
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