Demand Modelling
Variable demand models, 4-stage models, activity-based models, elasticty models, model audit
Variable Demand Modelling sits at the core of evidence-based transport appraisal. It captures how people respond to changes in cost, travel time, service levels and land-use policy. With over 20 years’ experience building TAG-compliant behavioural models, Amodellis provides specialist VDM services that deliver robust, policy-aligned and decision-ready forecasts.
Services Offered
TAG-Compliant VDM Development
End-to-end development of demand models consistent with DfT TAG, including:
- Mode, destination, time-period and frequency choice structures
- Pivot-point or absolute formulations for four- and five-stage models
- Elasticity-based or logit-based behavioural responses
- Full integration with highway and public transport assignment models
- Calibration, validation and sensitivity testing
VDM Enhancements & Elasticity Modules
We improve existing frameworks through:
- Updated exogenous costs and demand inputs
- New behavioural segments and assumptions
- Bespoke elasticity modules
- Benchmarking against DfT and international evidence
- Python scripting for bespoke analytical tools, including automation via Visum’s COM interface and the OpenPath Python API
Model Audits & Assurance
Independent technical reviews of VDM structure, assumptions and outputs to strengthen appraisal credibility.
Advanced Behavioural Modelling & Research
Whilst full activity-based and agent-based models require substantial research and development, we provide specialist behavioural and econometric support for organisations exploring these next-generation modelling approaches. Our expertise in discrete choice modelling and machine learning techniques are directly applicable to:
- Designing and estimating the choice models underpinning activity generation, mode and destination choice
- Developing behavioural rules and utility functions for agent-based frameworks
- Advising on model structure, segmentation and data requirements
- Reviewing activity-scheduling components drawing on recent research (including RNN-based scheduling work)
- Providing independent technical advice and research input for academic–industry collaboration projects
Scenario Testing & Policy Analysis
Assessment of impacts from:
- Pricing and charging changes
- Service and infrastructure improvements
- Land-use development scenarios
- Future travel conditions and behavioural shifts
Relevant Experience
PLANET Framework Model Update Audit - HS2 Ltd
Provided independent peer review for the PFM update, focusing on discrete choice and variable demand modelling. Supporting HS2 Ltd by advising on model robustness, methodological rationale, and alignment with best practice.
NorMITs Elasticity Model - Transport for the North
Enhanced the Northern Model Integration Tool with an elasticity-based adjustment model, underpinned by extensive benchmarking of demand elasticities.
VDM Development - Greater Bristol Area
Developed a multi-modal, TAG-compliant VDM with segmentation, demand responses and pivoting structures integrated into both public transport and highway assignment models.
Why Amodellis?
- 20+ years of behavioural and demand modelling experience
- Deep knowledge of DfT TAG requirements and UK appraisal practice
- Strong track record in independent model audit and technical assurance
- Active engagement in transport research
- Established links with academic researchers and universities
- Commitment to modern, data-driven and transparent modelling methods