|Developer(s)||TSS - Transport Simulation Systems|
|Stable release||Aimsun Online / 2008|
|Type||Traffic forecasting, transportation forecasting, road traffic control, congestion planning|
|License||Software license agreement|
Aimsun Online is used by traffic control centres to make real-time decisions about the management of a road network. It is used to dynamically forecast future traffic conditions based on the current state of the network and to evaluate incident response or traffic management strategies.
Aimsun Online slots right into the traffic control centre and continuously processes live field data, simulating vehicle movement inside a road network of any size, from a single highway corridor to an entire major world city. By combining these live traffic data feeds and high-speed simulations with emulation of congestion mitigation strategies, Aimsun Online can accurately forecast the future network flow patterns that will result from a particular traffic management or information provision strategy.
Aimsun Online was launched in 2008. It is built on the Aimsun platform which allows for static and dynamic modelling within the same software application.
Aimsun Online uses live traffic data feeds and simulations to forecast future traffic conditions for large urban areas and regional networks.
Aimsun Online analyses real-time inputs from disparate sources of information, such as field traffic controllers, detectors, incident reports and live data feeds from key intersections.
Calibrated model retrieval
Using up-to-date field data, Aimsun Online identifies, retrieves and loads a travel demand matrix of the road network being managed. It finds the closest match between the data received in real time from among several demand patterns stored in a database. The demand pattern database is created in a prior step by carrying out analysis of historical data.
This step involves dynamic (mesoscopic or microscopic) simulation of one or more scenarios in real time. Each scenario is simulated on a dedicated computer. The simulations produce dynamic forecasts of traffic conditions at a detailed, local level for the next 30-60 minutes. Each simulation considers a concrete set of actions that might be applied in order to improve the network situation. One of the scenarios always corresponds to the ‘do nothing' case.
The area included in the simulation model depends on the type of network being managed. It is typically defined using equilibrium assignment techniques which evaluate at a high level the impact of local but significant capacity changes on the rest of the network. The objective is to exclude areas that are unlikely to be affected by incidents or responses to those incidents.
Simulations typically last 1-3 minutes  depending on hardware specifications, network size and level of congestion (number of vehicles). These simulations are run in 'batch mode' (without animation in 2D or 3D) in order to improve performance.
Response information is presented visually online to provide support for operational decision making. Traffic control operators are provided with quick snapshots of predicted traffic flow and performance indicators for different control alternatives.
- Customisation to work with traffic control software
- Assimilation of new data to improve quality of predictions over time
- Online travel information systems
- Dynamic emergency vehicle routing
- Emissions management
- Accident response strategy assessments
- Urban and interurban congestion management
- Security threat mitigation and large-scale evacuation management
Aimsun Online is used to inform operational decisions for:
- Integrated Corridor Management Project on Interstate 15, San Diego, CA  The Intelligent Transportation Society of America (ITS America) awarded this project the Best Innovative Practices Award in the 2013 Best of ITS awards competition.
- Singapore City Centre
- M30, Madrid, Spain 
- Integrated Corridor Management on I-15 in San Diego, Traffic Technology Today, Dan Lukasik, A.: March 2013
- Traffic operations: Thinking ahead, Traffic Technology Today, Torday, A and Gerodimos, A.:17 Apr 2009
- Bola de cristal del tráfico, El Periódico de Catalunya, 23 Feb 2009
- Simulation times from Madrid, M30, project
- Project overview and links
- Report from European Transport Conference 2008