Travel demand modelling brings true integration
Four-step demand modelling is an important functionality for Aimsun software and another step towards true integration. You can now start a transportation modelling project from scratch, entering raw geographical and socio-economic data and follow the process all the way through to simulation without recourse to a separate package.
With Aimsun you no longer have to interface with an external traffic demand model for importing data as a starting point or as a means of redistributing demand from one mode to another or to estimate the impact that capacity changes have on overall demand levels.
Being able to use a single software application for an entire project means vastly increased cost-efficiency, consistency and quality for Aimsun users.
The Aimsun hybrid simulator gives you simultaneous microscopic and mesoscopic simulation, allowing you to model large areas while zooming in on all areas that require a finer level of detail.
Combining an event-based mesoscopic model with a more detailed time-sliced microsimulator offers a best-of-both-worlds scenario, blending superior computational efficiency with precise representation of traffic dynamics.
The hybrid simulator features the following:
- Definition of areas for microscopic simulation within a mesoscopically simulated network
- Legion for Aimsun available inside the microscopic areas
- Demand definition using O/D matrices or traffic states
- Unified statistics collection
- Look-ahead propagation between microscopic and mesoscopic areas
- Dynamic traffic assignment based on stochastic route choice
- Hybrid simulator applicable to sub-networks
- Dynamic traffic assignment based on dynamic user equilibrium
- Traffic management
Consolidate your traffic modelling in one multi-purpose, multi-layer simulation suite and see the benefits:
- Choose the right tool for the right project rather than creating projects to fit the tools.
- Build extensible simulation models on a larger and larger scale using a single all-in-one package.
- Eliminate cumbersome and error prone manual interfacing between different macroscopic, mesoscopic and microscopic software packages.
- Eradicate redundant work of maintaining separate networks in different packages.
- Reduce administrative and maintenance costs and expertise turnover.
- Modelling, simulation and output analysis in a single environment
- Intuitive, highly visual and mouse-driven user interface
- Simultaneous 2D and 3D (micro only) views
- Easy-to-visualise graphical outputs
- Copy and paste
- Table views for quick object searches
- Multiple project previsions
- Comparison of different scenarios
- External datasets (field measurements or other scenarios)
- Python scripting for automating repetitive tasks
One of Aimsun’s most outstanding features is its speed: our microscopic simulator is the fastest on the market by far and the finest microsimulation tool available in the world for large-scale projects.
Aimsun’s multithreaded software architecture speeds up the simulation process to such an extent that it completely redefines what can be included in a dynamic model, be that a major city or a large and complex highway network.
Even on a laptop, the Aimsun microsimulator can run a model of the whole of Singapore with 10,580 intersections and 4,483 km of lanes 2-3 times faster than real time. High speed simulation frees you up to:
- Simulate larger areas without leaving out problem zones
- Test a greater number of scenarios in the time available allowing for broader ‘what if’ analysis for a variety of traffic conditions
- Deal with time-critical situations
It’s not just our microsimulator that’s fast – the speed of Aimsun’s mesosimulator has enabled our users to build some of the world’s largest dynamic models in Montreal, Toronto and New York City.
Dynamic user equilibrium (DUE) techniques and stochastic/discrete route choice models are both available in Aimsun in combination with either mesoscopic or microscopic modelling. This framework gives you the unrivalled flexibility of modeling recurring and non-recurring conditions at the appropriate level of accuracy. But it doesn’t stop there: by reusing previously obtained static or dynamic equilibrium assignment routes in a new simulation and combining them with discrete route choice, Aimsun users are able to reproduce the blend of habitual driving and on-the-fly congestion avoidance that occurs in reality. The result? The tools for reproducing the most realistic representation possible of route choice behaviour under any conditions.
In addition, Aimsun’s rich traffic management framework allows you to model network operations that may have an impact on route choice:
- Parking schedules
- Cleaning schedules
- Turning closures during peak
- Reversible lanes
- Dynamically reserved lanes
Aimsun’s modular architecture and programming capabilities make it open to developing interfaces with a broad range of third party tools. Anything is possible, from traffic signal optimisation with the TRANSYT–Aimsun Link to emissions modelling with VERSIT+micro or even providing realistic virtual traffic conditions for the Oktal SCANeR driving simulation engine.
Aimsun fits right in with your existing software and can exchange data with the most popular CAD, GIS, transport modelling, signal optimisation and adaptive control software tools .
Multiplatform: Aimsun works on Mac OSX, Linux Ubuntu, Windows XP, Windows Vista and Windows 7. Multithreaded: for unbeatable speed. 64-bit: capable of handling very large models that can be built upon and added to.
Customisable and extensible: Make Aimsun your own using familiar industry standards such as Python and C++ in four different ways.
- Python scripting allows you to automate operations such as modifying model parameters; importing and exporting data; performing additional calculations on simulation outputs and launching multiple simulations or assignments.
- The Application Programming Interface or API is a collection of functions, in Python or C++, that allow you to include intelligent transportation systems (ITS) in the simulation. These include non-standard adaptive traffic control, advanced traffic management, vehicle guidance and many more.
- The Aimsun Microscopic Simulator Software Development Kit or microSDK enables you to override Aimsun’s behavioural models (car-following, lane-changing, etc.) and apply your own behavioural models, programmed in C++.
- Finally, the Aimsun Platform Software Development Kit or platformSDK gives you the power to create entirely new applications (plug-ins) with their own menus and dialogs; add new classes of objects to the database or extend the current ones; and access all information inside an Aimsun model file to perform any computation imaginable – all using industry-standard C++.
Superior software architecture
Pedestrian & vehicle interaction
Legion for Aimsun is a concurrent pedestrian and vehicle simulation solution that allows you to assess the interaction of vehicles and pedestrians. This is an essential tool for:
- public transport assessments
- safety analysis
- major event management
- urban environmental studies
Legion for Aimsun can handle up to 30,000 pedestrians an hour, running concurrent simulations of people and vehicles.
Pedestrian-vehicle interaction can range from boarding and alighting both public and private vehicles to crossing bridges and underpasses. Seamlessly integrated into the Aimsun microsimulator, Legion for Aimsun inherits Legion’s patented algorithms calibrated to actual measurements of walking speeds and personal space preferences as well as a world-class commercial track record that includes every Olympic Games event since 2000.
Network Revisions is part of a new set of Scenario Management features that has revolutionised the process of comparing and revising base and future scenarios.
Network revisions allows you to make a change in the base network model and apply the edit automatically to all related future scenarios, which cuts down menial copy-and-paste tasks and the probability of errors. With network revisions you can also simultaneously store different edits in individual future scenarios without affecting the base model and keep all the scenarios in the same file for easy reference.
- Cuts out the need to duplicate data between different scenarios
- Reduces error
- Speeds up the modelling process
Note: Aimsun has many options for accommodating several scenarios in the same network: demands, control plans, public transport schedules, traffic management actions, network attribute overrides, etc. The revision system is for when a modification (such as a change in the geometry) cannot be accommodated in the same network file.
Whenever two or more networks use the same output database Aimsun will list scenarios, experiments and replications from another network in the current network as External Scenarios. You can retrieve data from these external data sources and Aimsun will retrieve data for existing objects in the current network as long as the ID and type match.
Network revisions allows you to:
- Model, calibrate and validate the base network
- Create a revision for each new scenario
- Delete any scenario from the base network in the revision (to detect it as external and to have only relevant scenarios for this revision)
- Use the same outputs database for the base network and the revisions
- Aimsun will automatically list external scenarios (in the base and the revisions)
- Present and compare common data
Network revisions is part of the move away from throw-away, one-use models to the maintainance of a base model that you can use again and again for operations analyses: create the current state, make revisions for different projects and then whatever you have built is consolidated in the base model, which therefore remains up-to-date.
The FZP Exporter exports Aimsun simulations to Autodesk® 3ds Max® for high–quality three dimensional presentations, allowing you to immerse themselves in a very rich virtual environment with high-fidelity terrain and structures. You can attach to or detach from a vehicle and fly around the database, zoom in and zoom out, freeze the simulation, and resume.
Simulation data is generally available as two dimensional drawings or large tables that must be analyzed statistically, and it is difficult for non-modellers to interpret the impacts of these phenomena upon the rest of the transportation system. The FZP Exporter makes it possible to render the transportation system in 3D virtual reality, allowing researchers, analysts, planners and stakeholders to view the transportation system through virtual traffic cameras, traffic-monitoring helicopters, or first-person from an individual driver or pedestrian viewpoint.
City planners, traffic engineers, and other decision makers can apply this technology to various problems or purposes, such as the following:
- congestion/choke points
- the effectiveness of new technologies and highway improvements such as HOV lanes or other ITS deployments
- the effects of construction phasing and lane closures (allowing for ‘what if’ analysis for a variety of traffic conditions)
- the development of commercial or residential sites (e.g., value of visualisation)
The OpenStreetMap importer gives you amazing independence, allowing you to start a new project by importing the geometry of any place in the world in a matter of seconds without having to rely on anyone to provide the right material, or depending on another model’s network. It’s just you and your internet connection.