SECTION 2
MAINTENANCE STANDARDS, WARNING AND INTERVENTION LEVELS
HMPP2_02 / Issue Date:
MAINTENANCE STANDARDS AND INTERVENTION LEVELS
INTRODUCTION
Under section 58(2) of the Highways Act[1]the highway authority has a special defence against an action for damages for non-repair of highway, if the following criteria have been considered;
(a)the character of the highway, and traffic which was reasonably to be expected to use it;
(b)the standard of maintenance appropriate for a highway of that character and used by such traffic;
(c)the state of repair in which a reasonable person would have expected to find the highway;
(d)whether the highway authority knew, or could reasonably have been expected to know, that the condition of the part of the highway to which the action relates was likely to cause danger to users of the highway;
(e)where the highway authority could not reasonably have been expected to repair that part of the highway before the cause of action arose, what warning notices of its condition had been displayed;
This section defines the maintenance standards, warning and intervention levels to be used by this Highway Authority for roads, footways and cycleways in consideration of (b) and (c) above.
MAINTENANCE STANDARDS
The main reference document for maintenance standards is the Code of Good Practice[2], which contain national standards that have been established after research and represent a range of values, thus enabling a highway authority to select standards appropriate to its policies and local circumstances.
The maintenance standards and warning levels which follow have been grouped into the council’s maintenance budget headings for ease of reference.
1.Routine Maintenance
Cyclic Maintenance
These can be grouped into the following types of work:-
a.Verge Maintenance
The management of roadside verges to ensure the safe passage of vehicles and conservation of the flora, works include;
Grass cutting.
Weed control.
Tree Maintenance.
Hedges (only where maintained by Brighton and Hove).
Siding (removal of edge of verge encroaching upon carriage and footway width) .
Management of special verges (cutting only at specified times).
b.Gully Emptying, Drain Cleaning and Minor Repairs
The emptying of gullies and catchpits and hydraulic jetting of gully connections and drain runs, and minor repairs to gullies catchpits, grip clearing and cleaning gully tops and the drainage system.
c.Sweeping and Cleansing
The removal of debris and litter from carriageways and footways to keep them safe and generally clear.
CYCLIC MAINTENANCE STANDARDSGrass Cutting
Generally
Average of 11 cuts per year based on a performance specification of maintaining height between 25 and 60mm.
Special Verges
Areas of verge defined and marked as containing items of botanical interest will be specially maintained with grass cutting arranged to meet the needs of individual verges.
Note
i / The standards adopted for grass cutting will be dependent upon the funds available in the maintenance budget.
Weed Control
Street Furniture, Paved Areas and Kerbs/Channels
Weeds only treated using an herbicide from the council approved list.
2 sprays per year and hand grubbing as required.
Hedge Trimming (Highway Authority hedges only)
Once a year on roads where the responsibility of the Highway Authority adjacent to road/footway. Where there are special requirements in visibility areas, cutting is undertaken when required.
Tree Maintenance
All trees within and adjoining the highway should be inspected for dangerous conditions annually.
Siding
i. / On footways siding should be carried out to preserve an adequate width of footway for all types of pedestrian traffic.
Gully Cleaning
i. / Gullies cleansed twice per annum.
ii. / Gully tops cleared four times per annum.
iii. / Connections rodded as necessary.
Culverts, Manholes and Piped Drainage/Soakaways
i. / Cleaned on a reactive basis.
Note
i / Culverts refer to pipes with a clear opening less than 1.0m, spans greater than this are structures.
Traffic Signs
i / Cleaning when required.
Sweeping and Cleaning
i / All streets to be maintained to Environmental Protection Act Grade A.
2.Basic, Preventative and Structural Maintenance
Basic, Preventative and structural maintenance although separate types of work are, for the purposes of setting maintenance standards, interlinked. If preventative maintenance is not undertaken at a certain stage in the life of a carriageway or footway then at a later stage more expensive structural maintenance or basic maintenance measures will have to be undertaken.
There are two different types of standard which can be set for carriageway or footway, these are;
- Warning Levels
These are an engineering measurement and are used as a method for prioritising work on a needs basis, within the resources available.
- Intervention Levels
These are levels at which intervention needs to be considered and can include the size of particular defects which the highway authority would be expected to take remedial action. These can be found in HMPP2_05 - Guidance Notes for Inspectors when Undertaking ‘Safety’ Inspections.
It should be noted that the decision to undertake preventative or structural maintenance
work is one of engineering judgement and the availability of budgets. The ability to carry
out preventative and structural maintenance is dependent upon budgets. Basic
Maintenance remedial action required to correct defects will be given priority over
preventative and structural maintenance.
a.Carriageways
There are a number of modes of deterioration for carriageways with the condition being measured in the following ways;
(i)Whole carriageway minor deterioration
Potholing, fine crazing, permeable surface, fretting or signs of fretting, loss of chippings and fatting up of existing dressings will normally result in the application of appropriate surface treatments.
(ii)Whole carriageway major deterioration
Cracking, coarse crazing, loss of aggregate or serious permeability will require increasingly expensive attention.
(iii)Loss of skid resistance
This has obvious safety implications. Both general deterioration and site specific problems are considered.
(iv)Edge deterioration
This can take various forms and if left unattended can accelerate the onset of serious problems.
(v)Wheel track rutting
Wheel track rutting can be either plastic deformation of the surface or an indication of structural failure.
(vi)Adverse camber
Nationally specific values are not provided to deal with problems of adverse camber, but for general guidance action will only be taken where safety is being prejudiced.
(vii)Surface irregularity
Specific values are not provided to deal with problems which arise due to surface irregularity.
The following Warning Levels can be found in the Code of Good Practice (Chapter 3 Appendix 3.4), with the Category of road taken from the road hierarchy[i],
CARRIAGEWAY - WARNING LEVELSCategory of Road to which applicable / Limitation of severity / % of length or area / Treatments
(i) / Whole carriageway minor deterioration
2 - 4 / Notes 1 - 3 / 20 / Surface treatment
(ii) / Whole carriageway major deterioration
2 - 4 / Notes 4 -5 / 5 / Patch and surface treatment
2 / --- “ --- / 10
25 / Patch, overlay or resurfacing
major strengthening
3 / --- “ --- / 15
40 / Patch, overlay or resurfacing
major strengthening
4 / --- “ --- / 15
50 / Patch, Overlay or resurfacing
Major Strengthening
(iii) / Loss of Skidding Resistance
2 - 4 / Note 6 / 30 / Surface treatment
(iv) / Edge deterioration
All / Note 7 - 8
Severity 1
Severity 2
Severity 3 / 17
10
7 / Patch
Note 7 - 8
Severity 1
Severity 2
Severity 3 / 50
30
20 / Haunch and/or kerb
(v) / Wheel track rutting
All / Depth 20mm or more / 5
80 / Localised overlay or resurfacing affected length of rut
Overlay or resurfacing affected lane
Notes
1 / Surface treatments covers all forms of surface sealing techniques, including patching surface dressing using normal or special aggregates and binders, thin coating with dense materials.
With the commercial introduction of a range of improved binders and chipping application techniques surface treatments should be seriously considered as an alternative to resurfacing of all categories of road when minor carriageway defects emerge.
2 / Patching, either in isolation or prior to surface treatment, should always be carried out where required to ensure a uniform surface with the remainder of the road, and to remove isolated weak areas.
3 / Patching repairs should be considered when:-
i. / A pothole forms in any road which creates a safety hazard - see HMPP2_04
ii. / It is necessary to replace existing patching which has failed and failures of permanent trench reinstatements.
4 / No warning Level is recommended for the percentage of patching at which whole carriageway remedial treatment should be considered. This must be an engineering judgement, but as a guide it is considered that patching should not exceed 20% of the whole carriageway area.
5 / The treatments suggested may be used in the absence of better information from machine based structural condition assessment like, for example, the Deflectograph, Benkelman beam or falling weight deflectometer. such assessment should normally be carried out before selecting remedial treatment on the higher categories of road.
6 / Skidding resistance is dealt with in greater detail in HMPP2_06
7 / Edge deterioration severity’s are described as follows:-
Severity 1 / Where cracking, fretting or potholing of the edge of the carriageway is present, with a need for patching but with little or no over-riding of the verge.
Severity 2 / Where severe over-riding with or without rutting or potholing of the edge of the verge is present, either alone or with deterioration of the edge of carriageway, as for severity 1.
Severity 3 / Where serious deformation or cracking of the carriageway in the vicinity of the edge is present, with or without over-riding of the verge.
8 / Edge strengthening should be considered when it is necessary to repair:-
a / Edge deterioration which causes cracking, fretting, potholing and deformation of the carriageway.
b / Rutting and over-running which causes potholing of the edge of the verge or standing water.
b. Footways and Cycleways
There are a number of modes of deterioration for footways and cycleways;
- Projections (including manhole frames, boxes, etc.)
- Dangerously rocking slabs
- Cracks or gaps between slabs
- Isolated potholes
- Depressions and bumps
- Slippery surfaces
The following Warning Levels can be found in the Code of Good Practice (Chapter 3 Appendix 3.4), with the category of footway and cycleway taken from the hierarchy[ii].
FOOTWAY AND CYCLEWAY - WARNING LEVELSCategory to which applicable / Limitation of Severity / % of area / Treatment
I / Main shopping areas
(flexible) / Coarse cracking of the surface.
Coarse crazing.
Depressions more than 25mm deep.
Trips greater than 13mm but less than 20mm. / 20 / Restore surface
I / Main shopping areas
(rigid) / Trips more than 13mm but less that 20mm.
Cracks or gaps more than 20mm wide and more than 6mm deep.
Rocking flags which are not dangerous.
Depressions more than 25mm deep. / 20 / Restore surface
II / Busy urban/shopping (flexible) / As for Main shopping areas (flexible) / 30 / Restore surface
II / Busy urban/shopping (rigid) / As for Main shopping areas (rigid) / 30 / Restore surface
III / Less used urban (flexible) / As for Main shopping areas (flexible) / 40 / Restore surface
III / Less used urban (rigid) / As for Main shopping areas (rigid) / 40 / Restore surface
Notes
1 / Rigid refers to paved and concrete footways, all others are flexible.
1 / Choice of surface treatment will depend on the failure mode, type of construction and importance of the footway or cycleway. Generally less used footways would only require surface treatment and heavily used ones reconstruction of the surface. Although not specified separately, cycleways should be treated to urban standards in normal circumstances.
- Kerbs
The purpose of kerbs is to protect pedestrians, provide water channels, to lead surface water into gullies and to define and support the edge of the carriageway, e.g. to prevent overriding.
In addition to loss of upstand, deterioration may take any of the following forms;
- Longitudinal cracking
- Broken or missing
- Spalled
- Badly aligned
- Badly tilted, i.e.. more than 1 in 12
- Generally disintegrated
- Sunken channel blocks or setts
Apart from urgent repairs undertaken for safety reasons[iii], defective kerbs should be replaced generally in association with other carriageway or footway works.
The following Warning Levels can be found in the Code of Good Practice (Chapter 3 Appendix 3.4.
KERB - WARNING LEVELSGroup to which applicable / Limitation of Severity / % of length / Treatment
Inadequate kerb upstand
All / Total loss of upstand / 10-20 / Restore upstand if appropriate for location
Busy protected footway / Upstand 30mm or less / 100 / Ditto
Busy unprotected footway / Upstand 75mm or less / 100 / Ditto
Little used footway or no footways / Upstand 30mm / 100 / ditto
Kerb deterioration
With busy footways / As defined in above / 10 / Replace kerb
Other sites / 20 / Replace kerb
Need for kerbing
Unprotected footway / over-riding of footway. carriageway drainage discharging across footway. surface water not reaching gullies. edge deterioration of carriageway / 20 / Provide Kerb
Notes
1 / A footway is deemed to be protected when it is bounded on the roadside edge by pedestrian guardrails, bollards or similar protective measures.
- Drainage
The objective of highway drainage is supporting the principal objectives of structural maintenance by ensuring that surface water is removed from the carriageway as quickly as possible and not allowed to pond or penetrate to the foundations of the road.
DRAINAGE - MAINTENANCE STANDARDSDrainage Items Recommended Cyclic Standard
a. / Culverts and manholes cleaned when required.
b. / Grips and highway authority ditches should be cleared of vegetation and dug out when required.
c. / Piped drainage, soakaways and associated systems should be cleared when required.
Ironware in Carriageways
When boxes, frames and covers are found to be greater than 20mm lower than the surrounding carriageway, they should be re-set.
Gully frames should be maintained no lower than 10mm below carriageway surface level and a maintenance programme established to address this.
e.Roadmarkings and Roadstuds.
Maintenance and replacement of the existing roadmarkings and roadstuds.
ROADMARKING AND ROADSTUD - MAINTENANCE STANDARDSReplacement due to Maintenance Works
i. / Temporary warning signs must be provided where mandatory markings are removed and shall be retained until the permanent markings have been replaced.
ii. / Markings and road studs should be replaced as soon as economically practicable after completion of the surfacing works.
f.Traffic Signs (non-illuminated)
TRAFFIC SIGNS (NON-ILLUMINATED) - MAINTENANCE STANDARDSDescription / Standard
i / Cleaning / When required
ii / Replacement and repair of signs and bollards / The speed of permanent repair or replacement will depend on the degree of danger.
g.Fences, Barriers and Walls
Those safety barriers, pedestrian barriers, fences and small retaining walls owned by the Highway Authority.
FENCES, BARRIERS AND WALLS - MAINTENANCE STANDARDSDescription / Standard
i. / Painting / When required
ii / Cleaning / This is only expected to occur where safety barriers or guardrailings are being used in lieu of chevron warning signs.
Note
1 / A small retaining wall has a retained height less than 1.0m
3Structural Maintenance
The standards and warning levels for carriageway and footway works are the same as for preventative maintenance.
4Winter Maintenance
The main reference document for national standards is the Winter Maintenance Supplement to the Code of Good Practice[3], the following standards have been adopted by this Highway Authority.
WINTER MAINTENANCE STANDARDSPrecautionary Salting Treatment Times
Precautionary Salting
The application of salt to carriageways on priority routes usually in advance of frosty conditions often referred to as gritting or presalting.
Hilltop Routes
Two routes salted on marginal occasions where frost is liable to form on hilltops and known frost hollows furthest from the influence of the sea. The routes usually take less than 1½ hours each to complete.
Standard Routes
The most frequently instructed routes but does not cover the warmest areas identified by thermal mapping. Six routes cover main road, bus routes, emergency service depots, hospitals, important commuter routes, schools and shopping centres. The routes usually take less than 2½ hours to complete.
Full Routes
An extension of each standard route to cover the warmest areas and is usually instructed when a wet road is liable to freeze or in advance of snow. The routes usually take less than 3½ hours to complete unless it is snowing.
This authority aims to:
(i) / complete precautionary salting of priority carriageways before the road temperature falls to freezing point.
Salting Spread Rates
Precautionary Salting
Dependent upon temperature forecast / 10 - 20 g/m2
Post Treatment Salting
(i) / Prior to snowfall, dependent upon forecast conditions / 20-40 g/m2
(ii) / Snow already on the road - depths in excess of 30mm / ploughing and salting (up to 40 g/m2)
Hard Packed Snow and Ice
(i) / Air temperature above - 5oC / Successive salting at 20-40 g/m2
(ii) / Air temperature below - 5oC / Gritting with 50/50 mixture of salt and single size abrasive aggregate not exceeding 6mm or 5mm sharp sand may be appropriate depending on conditions.
Weather Forecast
This shall include as a minimum the following requirements:-
(i) / a detailed 24 hour road weather forecast;
(ii) / a 2 to 5 day forecast for planning purposes;
(iii) / a 24 hour Consultancy service;
(iv) / the timing of forecasts to ensure that they meet the authority’s decision making needs.
Road Danger Warnings are also to be received in October and April
5Traffic Signals
TRAFFIC SIGNAL - WINTER MAINTENANCE STANDARDSDescription / Standard
i / Lamp changing / Lamps are changed at 6 monthly intervals
ii / Mechanism/Electrical / Annually or when a fault is suspected
iii / External cleansing / Annually or when a fault is suspected
iv / Post painting / When required - condition reported when clean
v / Fault logging / Daily
Notes
1. / Remote monitoring systems linked to controllers via telephone lines report most faults which can occur.
6Highway Lighting and Illuminated Signs
aLight Source - Highway Lighting
LIGHT SOURCE - MAINTENANCE STANDARDSArea / Light Source / Key
Designated Conservation and Amenity / 50/70/100/150/250
Watt SON / SON:-
High Pressure Sodium
Other / 35/55/90/135/180
Watt SOX / SOX:-
Low Pressure Sodium
Notes
1. / Highway Lighting and Illuminated Signs will be lit from dusk to dawn using photoelectric cells.
2. / Subway Lighting will in most cases be lit 24 hours a day.
3. / The use of High Pressure Sodium (SON) will generally be restricted to main roads, busy junctions, conservation areas, amenity areas and town centres.
4. / The maintenance of lighting on the adopted public highway including footway lighting is the responsibility of the Council.
bHighway Lighting