Local Highway Maintenance Transparency Report
Our highway network
We are responsible for maintaining the following lengths of highway.
Lengths of highways, footways and cycleways
| Type of highway | Length in kilometres (km) |
|---|---|
| A roads | 57 |
| B and C roads | 138 |
| U roads | 363 |
| Total roads | 558 |
| Footways | 632 |
| Other public rights of way | 305 |
| Cycleways | 13 |
In addition to the highways listed above the Council is also responsible for the maintenance of:
| Asset | Number |
|---|---|
| Bridges | 106 |
| Retaining walls, culverts & subways | 209 |
| Street lights | 13,607 |
| Road Signs | 7,159 |
| Road gullies | 23,665 |
These assets are subject to a maintenance regime based on national code of practice recommendations, where applicable. For example, bridges receive a Principal Inspection every six years General Inspection every two years
Highways maintenance spending figures
| Year | Capital allocated by DfT (£,000) | Capital spend (£,000) | Revenue spend (£,000) | Estimate of percentage spent on preventative maintenance | Estimate of percentage spend on reactive maintenance |
|---|---|---|---|---|---|
| 2025 to 2026 projected | £3,076 | £3,076 | £1172 | 80% | 20% |
| 2024 to 2025 | £2,452 | £2,452 | £1,007 | 80% | 20% |
| 2023 to 2024 | £2,840 | £2,840 | £1,304 | 81% | 19% |
| 2022 to 2023 | £2,174 | £2,174 | £1,191 | 82% | 18% |
| 2021 to 2022 | £1,689 | £1,689 | £1,119 | 80% | 20% |
| 2020 to 2021 | £3,240 | £3,240 | £1,528 | 89% | 11% |
Information on capital funding allocated by DfT is available[external link]
Additional information on spending
Capital:
Capital budgets spent on roads and footways consist of a pre-planned programmes of works that use a wide range of maintenance techniques depending on the condition and requirement of the site. Broadly, DBC term them as Reconstruction, Resurfacing and Surface Treatment schemes.
- Reconstruction sites range from full reconstruction of the structural layers via the traditional method of excavation and replacement of all the various layers to insitu recycling, where most of the material remains on site and is recycled with additives and relaid with a new running surface.
- Resurfacing sites are the bulk of our forward works programmes and are made of schemes that requires the removal and replacement of the top bituminous surface.
- Surface Treatment sites treatments include products like Microasphalting and Surface Dressing. These surfacings seal the road from water ingress preventing potholes & other carriageway defects from forming whilst adding additional skid resistance.
- We also have programmes of ‘Ordinary Maintenance’ Patching and Spray Injection Patching works that are compiled from the Highway Inspectors routine safety inspections.
All Darlingtons Structures (Bridges, Retaining Walls etc) are part of a condition inspection regime which involves regular structural inspections. These Regular inspections are important to ensure the safety, longevity, and value of the asset. It helps identify potential problems early, preventing them from escalating into costly and disruptive repairs later. There is a programme of general maintenance type works such as vegetation and silt removal as well as stone/masonry repairs, crack stabilisation, jointing, scour repairs etc
Revenue:
The Revenue expenditure figures shown here include spending on such items as pothole & drainage repairs. We have not included cyclic items such as grass cutting, gully emptying or winter gritting as they do not involve maintenance to the fabric of the highway.
For 2024-25 approximately 31% of the available revenue budget was spent on carriageway Surface Treatment sites that include products like Microasphalting and Surface Dressing.
The remaining 69% of the revenue budget is spent on reactive maintenance which broadly consists of:
- Bituminous Patching (Primarily carriageway including pothole repairs)
- Concrete Paving (Primarily footway blocks and flags)
- Drainage (Primarily carriageway)
- Other (furniture, bollards etc)
|
Treatment (DBC Definition) |
2020/21 Quantity |
2021/22 Quantity |
2022/23 Quantity |
2023/24 Quantity |
2024/25 Quantity |
Planned: 2025/26 Quantity |
|
Carriageway Resurfacing / Reconstruction |
26,186m² 2.91 km |
49,876m² 6.676 km |
46,549m² 6.7 km |
30,226m² 4.479km |
60,875m² 7.097 km |
52,249m² 5.719 km |
|
Surface Treatment: Carriageway Micro Asphalt |
106,259 m² 15.157 km 71 sites |
77,196 m² 14.203 km 52 sites |
57,563 m² 9.051 km 46 sites |
37,551m² 5.595 km 29 sites |
22,778m² 3.363km 21 Sites |
8,232m² 1.220 km 4 sites |
|
Surface treatment: Carriageway Surface Dressing |
61,219m² 9.65 km 4 sites |
n/a |
n/a |
n/a |
4,120m² 0.392 km 2 sites |
21,427m² 2.350 km 2 sites |
|
Back Lane Improvement Schemes |
303m² 0.07 km |
551m² 0.120 km |
444 m² 0.065 km |
490m² 0.136km |
774m² 0.167 km |
606m² 0.146 km |
|
Footpath Improvement Schemes |
767m² 0.343 km |
1,645m² 0.788 km |
1,495 m² 0.701 km |
2,507m² 0.874km |
1,847m² 1.015 km |
492m² 0.262 km |
Table 1: showing quantity (Area/Length/Number of sites) of treatments per annum
In a bid to gain a more detailed understanding of the highway network, its condition and treatment requirements, in the autumn of 2023 DBC started to use Annual Engineering Inspections (AEI) that focus on treatment selection as opposed to a simple condition score. Following an on-site assessment, the AEI survey enables maintenance schemes and treatments to be identified easily and efficiently. The AEI is the only survey type to facilitate accurate maintenance solutions informed by an engineer while on site. This process delivers a true reflection of Darlington's road maintenance requirements in useful and meaningful standardised lengths of treatment.
Forward programming:
Using the AEI data we have established a 5 year forward programme that is based on actual treatments (Resurfacing / Surface Dressing etc) with additional locally set Value Management criteria (Hierarchy etc).
Condition Projection Model (CPM):
The AEI Data has also been used to produce a CPM for the next 20 years based on varying budget and spend profile scenarios to establish the optimum approach. Whilst budgets play a significant part in the condition of the highway network it is also prudent to spend the available budget on the right asset, at the right time, using the right product.
The CPM indicated Surface Treatments like microasphalting and surface dressing are a critical component for optimal deterioration and showed that the budget for highway maintenance would be best split in the following way: Structural (Reconstruction and Resurfacing) schemes at 60% and on Surface Treatments (Microasphalt / Surface Dressing) schemes at 40%.
Although Darlington have an established history of using these Surface Treatments products, at present, over recent years Darlington have a respective 80/20 split, it is intended to increase the percentage of Surface Treatments gradually over the coming years to align towards the 60/40 split if budgets allow.
When used at the correct time, surface treatments are fit for purpose and last at least as long as its anticipated life cycle (8-10years), demonstrated by the fact that there are significantly less potholes after resurfacing than in the year prior. For example, in the streets highlighted for resurfacing in 2014 there we're 257 potholes in the 12 months prior to surface treatment. However in the following 12 months after application there was only 15, and a total of 184 potholes for the whole 10 years since.
Footways:
In early summer 2025 DBC will be engaging with our survey partners to start using the Annual Engineering Inspection (AEI) surveys in the same manner as the carriageway. Allowing a treatment based prioritised programme of works for future maintenance and possible condition projection modelling.
Number of potholes filled
| Year | Number of potholes filled |
|---|---|
| 2024 to 2025 | 6,341 |
| 2023 to 2024 | 6,102 |
| 2022 to 2023 | 5,332 |
| 2021 to 2022 | 6,544 |
| 2020 to 2021 | 5,942 |
In 2024-25 45% (£321k) of the reactive maintenance budget was spent on repairing a total of 6,341 potholes. The number of potholes repaired each month (since April 2013) can be viewed on our website.
Condition of local roads
The condition of our network is shown below, including what percentage of our roads are in each category. The figures are broken down between the Classified A, B & C road network and the Unclassified roads. In 2024 we adopted a new survey method, the Annual Engineering Inspection (AEI), to replace the previous SCANNER & Course Visual Inspection methods. The AEI survey uses treatments rather than a numbered scoring system that gives our engineers more detailed information to target where work is needed. The survey is carried out annually on our entire road network (A,B,C and U) to give us the most up to date picture of current condition.
As we have changed survey method the two latest years (2023 onwards) figures are not comparable with the previous years.
Condition of A roads
| Year | Percentage of A roads in red category | Percentage of A roads in amber category | Percentage of A roads in green category |
|---|---|---|---|
| 2020 | 1.9% | 15.4% | 82.8% |
| 2021 | 1.3% | 13.0% | 85.8% |
| 2022 | 1.5% | 12.0% | 86.5% |
| 2023 | 7.2% | 33.5% | 59.25% |
| 2024 | 4.5% | 29.0% | 66.5% |
Condition of Other Classified (B and C) roads
| Year | Percentage of B and C roads in red category | Percentage of B and C roads in amber category | Percentage of B and C roads in green category |
|---|---|---|---|
| 2020 | 6.0% | 28.5% | 65.5% |
| 2021 | 5.4% | 27.1% | 67.5% |
| 2022 | 5.3% | 26.3% | 68.4% |
| 2023 | 4.7% | 27.4% | 67.9% |
| 2024 | 2.6% | 38.9% | 58.5% |
Condition of Unclassified roads
| Year | Percentage of U roads in red category | Percentage of U roads in amber category | Percentage of U roads in green category |
|---|---|---|---|
| 2020 | 13% | n/a | n/a |
| 2021 | 16% | n/a | n/a |
| 2022 | 17% | n/a | n/a |
| 2023 | 4% | 11% | 84% |
| 2024 | 8% | 19% | 73% |
Up to 2023 Darlington used SCANNER surveys for the A, B & C roads with Course Visual Inspection (CVI) being used for U roads. We have now moved to an approach where all roads have an AEI survey as previously mentioned. This means that the two latest years (2023 onwards) figures are not comparable with the previous three, but it also means that we now have a means of understanding and measuring the amber & green values of U roads.
For reporting and measurement purposes the treatments our surveys are used to produce a road condition indicator which is categorised into 3 condition categories:
- green – no further investigation or treatment required
- amber – maintenance may be required soon
- red – should be considered for maintenance
From 2026 to 2027 a new methodology will be used based on the BSI PAS2161 standard. Local Highway Authorities will be required to use a supplier that has been accredited against PAS2161. This new standard will categorise roads into 5 categories instead of 3 to help government gain a more detailed understanding of road condition in England.[external link] Our current survey supplier was implicit in setting up these new methodologies and as such will met these standards.
Plans
Overall strategy
The results of our independently obtained AEI surveys are fed into our dedicated analysis software to produce a prioritised forward works programme. Scheme prioritisation aims to deliver a repeatable and auditable scoring system applied to all available carriageway (and soon to be footway) schemes.
The objectives of the scoring mechanism are to generate a:
- score driven by condition / maintenance need.
- score that includes non-condition criteria, including factors that ensure a risk-based approach to scheme selection such as ride quality, skid deficiency, local hierarchy etc
- scoring mechanism that differentiates each available scheme from another.
This allows us to determine what treatment is appropriate, for example reconstruction, resurfacing or preventative surfacing. It also estimates how much funding will be required to treat each street allowing us to produce a costed and prioritised 5 year forward scheme programme.
Our reactive maintenance programme is determined by the results of the routine safety inspections which are carried out on every street. Town Centre streets are inspected every month, residential streets every quarter & main roads monthly. Back lanes are inspected annually. All safety defects identified on these inspections plus any brought to our attention via our public ‘Report It’ website are ordered for repair. The inspection frequencies are in line with the national code of practice for highway maintenance.
The quantities, area, length, number of sites etc for the current (25/26) year and previous 5 years can be seen in Table 1 above
Specific plans for 2025 to 2026
Our capital works Highway maintenance programme for 2025-26 includes:
- 4 ‘A’ road schemes totalling 2.4km
- 2 ‘B’ roads schemes totalling 0.43km
- 1 ‘C’ road scheme totalling 2.5km
- 14 Unclassified Road schemes totalling 4.2km
- 2 footway schemes totalling 0.27km
It is anticipated that the above mentioned planned maintenance schemes will stop approximately 820 potholes from forming. This is the equivalent of 14% of the average number of potholes per annum by targeting only 1.7% of road network (9.5km) with the correct treatments. A substantial percentage of potholes come from a small percentage of the network, by having a system like the one DBC uses we can identify these roads and footways to give us the most efficient outcome.
It is also estimated that our highway safety inspectors will issue orders for 5875 reactive potholes to be filled in based on the previous 5 year average.
Our capital works Structures maintenance programme for 2025-26 includes:
- Inspection of
- 47 road bridges
- 18 Prow
- and 28 Retaining Walls.
- We will also be carrying out numerous small to medium side maintenance repairs such as:
- 5 parapet renewals
- 7 masonry stitch repairs
- 4 scour repairs
- 8 fencing repairs and other general activities.
Streetworks
The Council adopted a permit scheme for road and street works in 2020 to promote a more effective system of co-ordinating works and managing the network. Permit applications are assessed taking account of their effect on road users while balancing the need of asset owners (such as gas, water, electricity & telecom) to maintain their apparatus & provide reliable services to their customers. Conditions can be attached to permits too, for example;
- limit the times & days when work can take place
- limit the hours when traffic lights can operate and when they need to be manually controlled
- what advanced publicity may be necessary ahead of the works.
The Council’s Year 3 Evaluation Report of the Permit Scheme is available to view on our website.
We hold quarterly co-ordination meetings with public utilities to discuss planned works. We communicate with our neighbouring Highway Authorities on any works near their border that could impact their network. We communicate major planned utility works through our website in consultation with the relevant utility as well as our own surfacing schemes, emergency works that could cause disruption are communicated through our social media page.
Climate change, resilience and adaption
Decarbonising our maintenance operations:
ADEPT Live Labs 2: Decarbonising Local Roads in the UK is a programme that uses cutting-edge material innovations to decarbonise local roads. Its is a three-year, £30 million, UK-wide programme funded by the Department for Transport that will run until March 2026, with a five-year subsequent, extended monitoring and evaluation period. Seven projects, grouped by four interconnected themes, are being led by local authorities working alongside commercial and academic partners.
Darlington has been following these various trials and noted that preservatives and rejuvenators are successful in protecting asphalt (roads) from environmental degradation and extend their lifespan. These treatments form a thin protective layer over the pavement, slowing down asphalt binder oxidation, preventing water intrusion, and minimizing UV radiation effects.
Preservatives are preventative maintenance - they do not repair significant damage but instead preserve the pavement in its current state. Darlington has always used this product as part of its ongoing maintenance regime.
The trials also showed the effective use of rejuvenators by restoring the chemical composition of aged asphalt binder by penetrating the pavement surface and improving pavement flexibility and durability. Darlington intend to trial use these products soon through the framework mentioned below.
We also have an annual programme of in situ recycling. This is a method of repairing carriageways by pulverising the existing road surface and foundation and mixing it with new materials, like cement or bitumen emulsion, to create a new, strong subbase. This process is typically done without removing the material from the site, making it a faster and more sustainable option compared to traditional road reconstruction
Savings through Procurement:
Since 2010 and in conjunction with the North East Purchasing Organisation (NEPO) Darlington have been the technical lead for the multimillion pound North East Highways Surfacing Framework that the north east authorities engage with to procure their highway surfacing materials. This framework is due for renewal in autumn 2025 and as such will have a revised and improved carbon reduction and sustainability strategy as part of its evaluation criteria. This would include improving the sustainability performance across several areas such as production plant, installation machinery, innovative materials, design solutions etc. When innovative new materials are proven and available to the authorities we will be adding additional Lots to the framework to allow Local Authorities to use such products as surface rejuvenation products.
After an initial trial period ending in 2023, Darlington decided to only use Warm mix materials where possible. Warm asphalt is mixed at around 40°C lower than an equivalent hot mix. This results in benefits from more efficient production, improved mixture workability, effective compaction at a lower temperature and a reduced cooling period required prior to trafficking. This, coupled with our use of insitu recycling, reclaimed asphalt products (RAP), single use plastics used in the manufacturing of bituminous material (where available) resulted in saving a total 348 Tonnes of carbon. This saving is equivalent to 872,150 miles driven by an average petrol-powered car or the electricity consumption of 227 average households for a year.
Savings through Asset management:
As previously mentioned, we use asset management principals to produce various condition projection models. These models allow us to reduce carbon through the application of optimised life cycle plans to determine future forward works programmes and their funding requirements. It then considers how works can be effectively prioritised to deliver the most effective maintenance, and how asset valuation and deterioration modelling can support effective investment programmes.
These outputs have shown that increasing surface treatments such as Microasphalt and rejuvenation surface penetration treatments can enhance the life expectancy of some roads. Darlington intend to carry on with the existing Microasphalting and Surface dressing programmes, and also intend to investigate the use of rejuvenators for future schemes.
The process is designed to increase awareness for highways maintenance practitioners to lead them towards better decision making and to adopt new technologies, materials and processes over the longer-term throughout the supply chain, reducing as far as practical the carbon costs associated with delivering maintenance works.
Sustainability commitments:
Climate change and its extreme weather conditions, of increased winter rainfall and more intensive summer rainfall in the summer with their associated flooding events coupled with increased summer temperatures accelerate the deterioration of our assets. By committing to net zero carbon and committing to adaption with new products, technology and condition monitoring we hope to minimise the deterioration
In 2019 Darlington Borough Council declared a climate emergency, and a high-level strategy and a supporting action plan was produced. In July 2023, recognising the increased urgency of action, the Council reaffirmed the climate emergency, bringing forward the date for the Council to be carbon neutral to 2040. We are also part of the Tees Valley’s Net Zero Strategy, Highway Asset Management is playing its part in ensuring these policies are met.