Activity-based modelling
We model people’s days, not just trips.
Classic four-step models treat trips independently. Activity-based models recognise that travel derives from the need to take part in activities: the sequence, duration and location of home, work, school, shopping, care and leisure activities are determined together. A parent who drops a child at school is more likely to drive to work than someone commuting directly.
The model starts from a synthetic population representing the study area by age, household structure, employment and car ownership. For each person a daily activity schedule, destinations, timing and mode choice are generated, and the resulting trips are assigned to road and public transport networks, so every mode is assessed in one consistent framework.
This answers questions beyond total traffic: whose journeys does a new line shorten? How does parking pricing affect different groups? How does flexible working reshape peaks? How many children could walk to school with safe routes?
- Synthetic population: a representative population with household and person attributes
- Activity schedules: sequence, duration, location and timing of activities
- Mode choice: walking, cycling, micromobility, public transport, car and shared options
- Assignment: loads, journey times and transfers on road and public transport networks
- Policy testing: pricing, routes and frequencies, cycle networks, land use and timing
Model scales
The right model is the one at the right scale.
Not every transport question needs a city model, and not every junction question is solved by one capacity calculation. Analytical capacity methods are often enough for a single junction’s signal plan. Where closely spaced junctions interact through queues, and pedestrians and public transport mix with traffic, microsimulation is required. When the question is how a new road, bridge or development area will change routes and mode choice across the city, a demand model is used.
At any scale, a model is credible only insofar as it reproduces observed conditions. We treat calibration and validation (testing against observations not used in calibration) as separate steps and report the fit criteria explicitly.
- Junction analysis: capacity, delay and queues at signalised, priority and roundabout junctions
- Microsimulation: interaction of vehicles, pedestrians and public transport along corridors
- Demand model: trip generation, distribution, mode choice and assignment at city or corridor scale
Key questions
Which questions does this study answer?
- How will changes in population, employment and land use affect travel demand?
- How will road, junction or public transport schemes change journey times, routes and network load?
- Which option is most robust under different demand assumptions?
- How well does the model reproduce observed conditions, and how reliable are the results?
Workflow
How we work
- 01
Model scope
We set the study area, assessment year, analysis hours, modes and model scale according to the decision.
- 02
Network and demand data
We assemble the road network, junction geometry, signal plans, public transport routes and demand data, and log gaps and assumptions.
- 03
Calibration and validation
We adjust parameters to counts and journey times, report fit with accepted measures such as the GEH statistic, and validate against independent data.
- 04
Scenario assessment
We compare options with the same indicators. For microsimulation we run multiple random seeds and report both mean results and variability.
Deliverables
What you receive
- Model scope, network structure and data sources
- Demand assumptions and calibration/validation report
- Scenario comparison of journey time, delay, queue and network load
- Sensitivity analysis: how results change if demand assumptions change
- Uncertainties, model limits and technical commentary for planning decisions
- Simulation visuals and presentation material on request
Model outputs show expected conditions under specific data and assumptions. An improvement in traffic flow does not in itself mean better accessibility, road safety or lower emissions; these are assessed with their own indicators.
Getting started
What to share with a modelling request
- The question to be answered and the options to compare
- Study area and assessment year
- Existing counts, signal plans, previous models and studies
- Any method, software or format required by the authority
We can start the first call even if not all documents are ready.
FAQ
Questions about this service
What is an activity-based model and how does it differ from a classic traffic model?
Classic models treat trips as independent numbers. An activity-based model simulates the activities people take part in during the day (home, work, school, shopping, leisure) and the trips between them as a chain. Walking, cycling, micromobility, public transport and car choices are assessed together, and the effect of a transit line, parking policy or land-use decision can be shown for different population groups.
Which methods and software do you use?
We choose the method to suit the decision: junction capacity analysis, traffic microsimulation, strategic demand modelling and GIS-based spatial analysis. If the authority requires specific software or formats, we plan accordingly.
Do you only look at vehicle traffic?
No. Our models treat walking, cycling, micromobility, public transport and car trips together. Alongside delay and queues we assess pedestrian crossing times, cycle links, public transport access and transfers, and show whether improving one group’s journeys penalises another.