How Hertfordshire County Council transformed highway and structures planning using AIM.

Maximise valuePlan for resilienceValue public outcomesTarget net zeroEmbed climate thinkingInclude uncertaintyMaximise valuePlan for resilienceValue public outcomesTarget net zeroEmbed climate thinkingInclude uncertainty
Client:
Hertfordshire County Council
Location:
UK
Consulting Partner:
Probit (direct implementation)
Asset Types:
Roads (A, B, C, U), bridges, retaining walls, gantries
AIM Version Used:
AIM 4.0
Key Outcome:
Integrated optimisation of highway and structures planning, reducing scenario times and enabling strategic, whole-life decision-making

Hertfordshire County Council (HCC) manages over 5,100 km of local roads and a wide range of associated assets, including bridges, retaining walls, and gantries, in the UK county of Hertfordshire, north of Greater London.

With an annual budget exceeding £1 billion, HCC is recognised as a leader in highway asset management. To maintain its infrastructure efficiently and cost-effectively, the council sought to upgrade its investment planning capabilities with a faster, more transparent, and integrated solution.

The challenge

HCC faced significant limitations in its existing investment planning tools.

For its road network, the legacy system was slow, taking days or even weeks to run scenarios, and difficult for internal teams to use. This created uncertainty and limited its ability to answer complex investment questions. For civil structures, the Excel-based SAVI tool was respected but functionally isolated, making it hard to use council-wide.

HCC needed a single, streamlined platform capable of integrating road and structure asset planning, improving efficiency, user adoption, and long-term decision-making.

Who worked on this project?

This was a direct collaboration between Hertfordshire County Council and Probit.

Probit configured AIM to replicate and enhance the council's existing models, including full integration of SAVI, and provided consultancy support for data preparation, model development, and team training.

HCC was a founding contributor to the original SAVI methodology, and its technical expertise helped shape the project. The result was a robust, user-friendly platform aligned with HCC's strategic objectives and national frameworks.

Probit

How was AIM used?

AIM was deployed as HCC's central web-based platform for asset investment planning, covering both highways and structures:

  • Road Network Planning (HDM-4 model) - AIM modelled the deterioration of individual road segments and selected optimal interventions across flexible time windows. The optimisation engine (powered by Gurobi) generated long-term maintenance strategies, from surface dressing to full reconstruction, aligned with budget and performance targets.
  • Structures Investment Planning (SAVI model) - AIM's Risk Map module embedded the SAVI model directly, enabling condition scoring, deterioration modelling, and valuation for structures such as bridges and gantries. This eliminated the need for standalone spreadsheets and ensured alignment with CIPFA/HAMFIG guidelines.
  • Advanced Scenario Optimisation - The platform supported long-range planning (15 years for roads and up to 120 years for structures), enabling HCC to explore multiple funding, performance, and policy scenarios in parallel.
  • Streamlined Data & Reporting - AIM managed HCC's asset data with full transparency and enabled in-house control of modelling assumptions and logic. Outputs were available through configurable reports and dashboards, ready for stakeholder engagement.

The results

The deployment of AIM at HCC led to significant and immediate improvements:

  • Planning cycle times cut from weeks to minutes, unlocking rapid scenario testing.
  • Greater internal control over modelling parameters and reporting, improving transparency and confidence.
  • Broader internal adoption, thanks to AIM's intuitive web interface.
  • Improved strategic insight, with more robust answers to complex planning questions.
  • Cost savings, particularly in structures planning, through better optimisation of whole-life value.

AIM replaced multiple legacy tools with a single integrated platform, helping HCC meet regulatory, fiscal, and public expectations.

“AIM delivered HCC vastly improved control over modelling parameters and reporting, while planning cycle times were cut from weeks to minutes.”

Dr Phil JonkergouwManaging Director, Probit

Technical insight

AIM's configuration for HCC embedded two industry-standard methodologies, HDM-4 for road assets and SAVI for structures, into a single, powerful modelling environment.

Using AIM's advanced and fast analytics and optimisation engine, the council could process over 5 million asset segments, run sophisticated constraint-based scenarios, and explore dozens of planning scenarios in real time.

Model logic and deterioration curves were fully transparent and editable, ensuring compliance with UK accounting standards and enabling scenario stress-testing.

AIM's scalability and web-based access made it ideal for large, multi-asset authorities like HCC.

What followed for HCC and AIM?

HCC plans to consolidate additional asset classes into AIM and continue building a fully integrated asset management approach.

Probit will support the rollout with ongoing consultancy, including data processing and team training.

As pressures on infrastructure funding grow, HCC aims to use AIM to deliver smarter investment, improved accountability, and long-term public value.

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