Scrutiny of Highway Maintenance 17 th June 2011 www.hertsdirect.org
Introduction to the Topic Chris Allen-Smith Service Manager (Asset Management & Maintenance) www.hertsdirect.org
Agenda • What are the pressures and challenges? • How are roads made? • Why do they need maintenance? • What types of maintenance are there? • What treatments are available? • What is our strategy? • What do we mean by ‘Whole Life Cost’? www.hertsdirect.org
What are the challenges? • Road condition has improved slightly in the last ten years but may now be slipping back due to recent harsh winters. www.hertsdirect.org
What are the challenges? • Road maintenance spending has not increased in real terms in the last ten years, only keeping pace with inflation. www.hertsdirect.org
What are the challenges? • Resources will reduce in the future due to spending cuts www.hertsdirect.org
What are the challenges? • At the same time councils face challenges from increasing traffic , high public expectations , bad weather and substantial cost inflation . www.hertsdirect.org
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• Multiple small-medium towns • One million residents • 277,000 cross-boundary commuters • 362,000 live & work in Herts • Poor East-West rail links • 5,000 km of roads www.hertsdirect.org
How are roads made? • Roads are built in layers • Surface layers - usually asphalt – Surface for traffic – Provides grip – Waterproofs the road – Gives some strength • Structural layers – usually stone – Provides shape and strength www.hertsdirect.org
How are roads made? • Construction Varies • Designed Roads – Thick construction – Strong • Evolved Roads – Most of the network – Thin/uneven construction www.hertsdirect.org
Why do roads need maintenance? Asphalt surfaces: • Lots of different types/names – similar job • Mix of different sizes of stone • Bound together with bitumen – Bitumen is oil-based – Oxidises over time – Becomes brittle & cracks – Water can get in www.hertsdirect.org
Why do roads need maintenance? Asphalt surfaces: • Water freezes in winter widening the cracks • Water can penetrate to lower layers, causing damage • Keep the surface sealed! www.hertsdirect.org
Why do roads need maintenance? Structural layers can develop problems due to: • High numbers of very heavy vehicles • Poor ground conditions • Utility reinstatements • Need expensive repairs • Fortunately rare www.hertsdirect.org
What types of maintenance are there? • Reactive repairs – Reactive fix to immediate problem (e.g. fill a pothole) • Planned repairs – Planned work to restore condition/service (e.g. patching works) • Planned maintenance – Planned work to maintain condition (e.g. surface sealing) www.hertsdirect.org
What types of maintenance are there? • More planning and less reactive = lower cost Cost to treat 1 sq m 180 160 140 Typical Cost 120 100 80 60 40 20 0 e h e s l c o c s t a e h a f r t P r D o u P s e R www.hertsdirect.org
What treatments are available? • Many different options: – Short term repairs – Longer term repairs – Surface treatments – Resurfacing – Reconstruction www.hertsdirect.org
Short term repairs • Temporary, cold pothole fills – Used to keep the road safe – Expensive – Not very durable – Often seen as poor value www.hertsdirect.org
Longer term repairs • Patching with hot material • Jet patching – Can be repairs on their own – Or preparation for further works www.hertsdirect.org
Surface treatments Surface dressing: • Hot liquid binder & stone chips laid on existing road surface • Seals the surface • Restores texture & grip • Quick to apply • Low cost (£5 - £8 per m 2 ) www.hertsdirect.org
Surface treatments Micro asphalt: • Cold emulsion of binder & stone laid on road • Seals the surface • Regulates minor dips • Restores texture & grip • Quick to apply • Low cost (£8 - £13 per m 2 ) www.hertsdirect.org
Resurfacing • Existing surface removed & replaced, possible lower layers too • Restores texture & grip • Restores ride quality • Reasonably fast • Costs vary (£15 - £50 per m 2 ) www.hertsdirect.org
Recycling • Replaces the surface • Restores texture and grip • Extends road life • Restores ride quality • Creates/restores structural layers of quieter roads • Quite expensive (~£35 per m 2 ) www.hertsdirect.org
Reconstruction • Replaces the surface • Restores texture and grip • Extends road life • Restores ride quality • Creates/restores structural layers of the road • Expensive (£40 to £100 per m 2 ) www.hertsdirect.org
What is our strategy? Category (Cat) 1 works: – Entirely reactive – Fix immediate hazards – Focused on safety – Expensive – Poor value (but necessary) www.hertsdirect.org
What is our strategy? Category (Cat) 2 works: – Mostly planned repairs – Reduce Cat 1 defects – Maintain serviceability by fixing non-hazardous defects – Delay need for more extensive works www.hertsdirect.org
What is our strategy? Category (Cat) 4 works: – Mix of planned repairs and preventative maintenance – Maintain asset for the future – Optimise long-term condition – Deliver value for money – Focus available money where it gives greatest benefit www.hertsdirect.org
What do we mean by ‘whole life cost’? • Audit Commission: ‘minimise whole life costs’ • Core principle of asset management – look at long term, not just immediate implications • More of the detail later - introduce the concept www.hertsdirect.org
Consider alternative strategies… www.hertsdirect.org
Put ‘whole life costs’ against each… e.g.: • 6 x £5 = £30 • 3 x £25 = £75 • 2 x £50 = £100 www.hertsdirect.org
Consider other factors… What implications might each option have for: • Reactive costs (like potholes) • Impact on traffic on the network Often this means a cheaper, preventative treatment is best value for money but that is not always the case, for example… www.hertsdirect.org
Applying WLC to case studies A414 London Colney Roundabout: • Accident problem • Poor lane definition a cause • Initial proposal – define East to West route using anti-skid surfacing • But anti-skid is – Expensive – Not very durable www.hertsdirect.org
Applying WLC to case studies A414 London Colney Roundabout: – Same solution, different material – Coloured conventional asphalt – Marginally higher initial cost – Four times the life – Much lower WLC www.hertsdirect.org
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