What’s that defect?

There is a central body responsible for the operation, maintenance and improvement of roads. In England it is Highways England who has an obligation to provide safe roads and reliable journeys for the road user, Scottish roads are managed by Transport Scotland, Welsh roads by the Welsh Assembly, local roads by the relevant local authority and roads in London by TfL (Transport for London).

In the English instance Highways England are responsible for the motorways and major trunk roads which totals around 4,300 miles (about 2% of all roads in England by length). Whilst only a small number the roads carry a third of all traffic by milage and two thrids of all heavy good traffic.

Under the Highways (Miscellaneous Provisions) Act 1961, highway authorities have an obligation to maintain public highways to reasonable standards and this is done with the help of a document which is used by the maintainers called the Routine and Winter Service Code (RWSC). This RWSC identifies the Category of the defect, the duration of any hazard mitigation and the permanent repair period duration for the contractual timeframe.

The definition of a Cat 1 defect as defined in the RWSC is;

  • Defects are those that require prompt attention because there is an immediate or imminent safety risk
  • Significant disruption to the normal flow of traffic through the Network
  • Structural deterioration
  • Damage to the environment
  • Offence to road users from graffiti that is obscene, blasphemous or otherwise offensive

The definition of a Cat 2 defects as defined in the RWSC are sub-divided into two categories;

  • Category 2.1 – Not superficial
  • Category 2.2 – Superficial (i.e. does not change the characteristic or function of the asset/item)

To keep it interesting we can look at Cat 1 defects which need us to make safe, permanent repairs within a contractual time frame and defects that, due to their nature and/or location, require intervention from an Incident Support Unit (ISU) within the contractual response times. This will all vary depending upon time of day and location and can either be dealt with immediately by a Network Maintenance Crew, an ISU or where it requires a more expansive response; such as lane closures or traffic management to protect the road user whilst hazard mitigation works take place.

Initially Cat 1 defects can be dealt with in 2 different ways: reactive or proactive, and with everything else the second respective is always better.

Reactive maintenance – Cat 1 defects identified by an external third party source…Police, Highways England Traffic Officers, Local Authorities or occasionally even direct via the public.

Proactive maintenance – Cat 1 defects identified by the Incident Support Units, depot based operatives, office based staff or Inspection teams driving the Network.

In addition to those defects listed in the bulleted points above we can look at defects as examples going forward and what constitutes a Category 1 defect. As always the caveat within the RWSC is that any list should not be regarded as exhaustive, because ultimately a defect can appear at anytime with anything on any Network, this ultimately just makes life that little bit more interesting and challenging.

To get a full idea of what to look for under Cat 1 defects (and in no particular order) I am going to ask around for examples from my contacts and look at the following over the coming months;

  1. Potholes and other local defects in the carriageway/footway/cycle track, including defective ironwork
  2. Excessive standing water and water discharging on to and/or flowing across the road
  3. Damaged road restraint systems and other barriers
  4. Debris and spillage in traffic lanes or on hardshoulders
  5. Kerbing, edging and channel defects
  6. Damaged lighting columns and other street furniture
  7. Damaged, defective, displaced or missing traffic signs or signals
  8. Dirty or otherwise obscure traffic signs and signals
  9. Trees, shrubs and hedges which by virtue of their position or condition constitute hazard to road users and the travelling general public
  10. Displaced roadstuds (particularly the cast “Catseye” type) lying in the carriageway, hardshoulder or laybys
  11. Defective, missing or loose roadstuds
  12. Faults in road structures e.g. impact damage to superstructures, supports or parapets, flood damage, insecure expansion joints
  13. Damage and defects in structures carrying water beneath the roads
  14. Difference in level (exceeding 20mm) between abutting concrete slabs at transverse or longitudinal joints in the carriageway/footway/cycle track
  15. Rocking gratings or covers in urban areas causing intrusive noise
  16. Damaged boundary fences where animals or children could gain access
  17. Defective road and sign lighting
  18. Overhead wires in a dangerous condition
  19. Blocked gully and piped grip gratings and obstructed channels, grips and slot drains
  20. Earthslips where debris has encroached or is likely to encroach on to the road
  21. Rocks or rock faces constituting a hazard to road users.

What’s that defect… Potholes

Keeping our roadways in good condition is a challenging problem due to harsh weather, unexpected traffic load, accident damage, changes in wheel load locations and normal wear and tear. All these factors degrade even new roads over relatively short periods of time.

As cost constraints and maintenance budgets tighten under the current austerity measures determining which roads need fixing becomes important process and with the introduction of the new Smart Motorway Systems throughout the country trafficking of the joints in the pavement is becoming more prevalent and giving rise to a greater number of failures on the network.

A pothole is a structural failure in the road surface where there is a loss of carriageway surface material resulting in a void being formed, and/or, a void in the carriageway surface layer that requires prompt attention because there is either a significant safety risk to the travelling public or major disruption to the normal flow of traffic. They need two things to form. Water and traffic, something which we have plenty of. The depression itself penetrates all the way through the surface course down to the base course and is the result of moisture infiltration and usually the end result of untreated crazing. As crazing becomes severe, the interconnected cracks create small chunks of pavement, which can be dislodged as vehicles drive over them. The remaining hole after the pavement chunk is dislodged is called a pothole.

There is no formal definition for a pothole recognised nationally. A pothole for this instance has been defined as a sharp edged depression anywhere in the carriageway where part or all of the surface layers have been removed and is identified when its maximum horizontal dimension is greater than 300mm and is 40mm+ in depth:

The following are for guidance only as smaller voids in more heavily trafficked areas may also be Cat 1 defects from my experience of Maintenance;

  • Voids with dimensions of 40-50mm in depth and 300mm in any direction should be considered a Cat 1 defect with a 24 hour response.
  • Voids greater than 50mm in depth and greater than 300mm in any direction should be considered a Cat 1 defect with emergency response and requires immediate attention