Does National Highways’ Draft Road Investment Strategy 3 (RIS3) put enough emphasis on preventative road maintenance strategies, to meet its objectives of managing road condition, securing network resilience, reducing carbon and reducing impact on road users?
That is the question raised by the Road Surface Treatments Association (RSTA), after the publication of the Draft Road RIS3. The document states that: “The main implications for the SRN are likely to be increased severe weather: more rainfall, high winds and extreme heat. This will impact road surfaces and embankments, and create operational challenges caused by a higher number of flooding and high-wind events. National Highways should therefore consider changes to the way in which the SRN is operated and maintained, to improve the resilience of the network and minimise impacts on overall performance and user experience.”
Mike Hansford, Chief Executive of the RSTA said:
“This need to secure resilience, in light of climate change impacts, supports a case to invest in preventive road maintenance strategies; planning the sealing of newly constructed or resurfaced roads from year 5 (widely recognised as a point of onset deterioration), to prevent water ingress and provide a barrier to the elements, keeping good condition roads in good condition for longer and therefore more resilient.
Untreated roads will continue to naturally degrade due to exposure to the elements and the effects of trafficking, leading to potholes, and eventually progress to end of life and require replacement. Whilst ‘preventative maintenance’ is referenced once in the document, there does not appear to be any clear indication that there is a budget for surface treatments in RIS3, so I am unsure how these objectives can be met.”
Local highway authorities are now required by the Department for Transport to declare the percentage of their maintenance funding being invested between both reactive and preventative maintenance activities, recognising good practice in road maintenance. Therefore RIS3 offers an opportunity to National Highways to set an example and set out a balanced road maintenance strategy of both reactive and preventative maintenance.
Major roads such as the M25 and the M40 have been successfully kept in good condition for longer using preventative treatments, for example. In fact, last year, the M40 was rated the motorway with the best journey experience in England in a survey of drivers by the independent watchdog, Transport Focus.
In the latest Strategic Roads User Survey the motorway between London and Birmingham had the highest overall satisfaction at 79 per cent, with motorists particularly praising the road surface. Asphalt preservation has been applied incrementally to the M40 since 2008, to protect and preserve it, keeping the road surface in good condition for longer.
In relation to the draft strategy, Transport Focus has made several recommendations including better management of roadworks and unplanned delays, as well as increased reliability of journey times and shorter journey times.
It will also expect National Highways to follow an approach of proactive asset management and preventative maintenance during the RIS3 period to support the long term management and planning of the network.
“All of these recommendations could be supported by the use of surface treatments as they are cost effective, use less traffic management and take a much shorter time period to be completed, causing far less disruption to users on the network whilst removing a significant amount of carbon from the maintenance process,” adds Mr Hansford. The draft document references that “…road surface renewals can reduce the need for reactive maintenance….”. This is an expensive reactive, replace on fail strategy.
Investing in road surface renewals, often from years 10-15, can cost up to ten times more per m2, compared to preventative asphalt preservation or rejuvenation treatments at year five. Even if re-applied every five years, there is still a long-term saving of up to 50%.
Preventative treatments would also cut disruption on the network significantly, with up to 40,000m2 of preservation or rejuvenation treated per shift (preservation can be applied at night). Roads having progressed onto mid life condition with minor surface damage, could be treated with Cold Applied Ultra Thin Surfacing (CAUTS), which still offers both cost and carbon savings.
Road surface renewals at 40mm (surface course) uses 7.2471kgCO2/m2. Preservation uses 0.3278 kgCO2/m2, or rejuvenation 0.0328 kgCO2/m2. Microsurfacing uses 1.7892 kgCO2/m2. So there are huge carbon savings to
be made. Low carbon, cost effective methods of reconstruction, such as cold recycling-(either in-situ or ex situ) could be considered to help restore life to roads on the network that are 50 years old, which is mentioned in the draft strategy document.
(Pic: Dft)
