Traffic management at the speed of life
Aimsun Online is a real-time decision support system for traffic management. Its dynamic, high-speed simulation of large areas allows traffic operators to “see” traffic conditions before they actually unfold and anticipate future events. It’s fast too: 2-5 minutes is all Aimsun Online needs to produce comprehensive traffic predictions for the next half hour.
A vision of the future
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 applications
Aimsun Online is the perfect engine for any Advanced Traveller Information System (ATIS) or Advanced Traffic Management System (ATMS), allowing for a wealth of applications:
- Predictive travel time calculations
- Intelligence-based Transit DSS
- Online travel information systems
- Dynamic emergency vehicle rerouting
- Dynamic route guidance
- Emissions management
- Accident response strategy assessments
- Urban and interurban congestion management
- Security threat mitigation and large-scale evacuation management
Smart traffic management
Simulation has the potential to significantly improve the accuracy and relevance of travel-time forecasts. Because it takes capacity changes and network effects into account, it is the only technique that can allow operators to compare the effectiveness of complex alternative traffic management strategies quickly and objectively, leading to:
- More effective and efficient incident management
- Reduced incident impact and quicker recovery period
- Earlier dissemination of incident information to the public
- Reduced manpower resources
- Shorter journey times and, as a corollary, increased economic savings
The future is now
Aimsun Online takes an accurate reproduction of the current traffic status as the starting point for the forecasting process. By comparing the records from the previous 30 minutes with the historical patterns in the database, Aimsun Online allows you to load the appropriate trip tables (Origin-Destination matrices) and simulate the network under its current capacity status. This sophisticated, simulation-based monitoring procedure is supported by time-series analysis and not only produces accurate travel-time forecasts but also offers advanced incident detection capabilities.
Strategy comparison without the guesswork
Unlike traditional analytical forecasting processes, a simulation of individual vehicles permits an explicit and faithful emulation of ITS policies such as:
- Ramp metering
- Signal coordination
- Lane reversals
- Variable speed limits
- Traffic information systems
This allows Aimsun Online to reproduce traffic management strategies and compare quantitatively their ability to mitigate congestion before their implementation in the field.
Customised performance indices
The comparison between strategies relies on the ability of Aimsun Online to synthesise huge amounts of simulated data in unique performance indices. This allows control centre operators to review the future network status and choose the best strategy by consulting a series of concise, individually rated temperature maps. Most importantly, these measures of effectiveness are not fixed but can be customised so that they correspond faithfully to the traffic management policies that a road authority wishes to put in to action. With access to individual vehicle delays, travel times, position, pollutant emissions, speed, route and many other characteristics, the measures of effectiveness can be as complex as you like.
Rich dynamic traffic assignment
One of the key elements that make Aimsun Online a unique solution for real-time forecasting and information provision is its innovative combination of dynamic traffic assignment (DTA) techniques. Aimsun Online features a rich combination of DTA techniques within the same simulation to give the most realistic representation possible of network behaviour. Dynamic user equilibrium (DUE) techniques and stochastic route choice models are both available in Aimsun and can be combined with either mesoscopic, microscopic or hybrid modelling. This gives you the flexibility of combining planning applications (modelling steady-state behaviour under recurring conditions) with operational assessment, (looking at short-term capacity and demand signals for non-recurring situations such as road works or short-term lane closures). Aimsun’s DTA model analysis results can be used to evaluate many more meaningful measures related to individual travel time and cost, as well as system-wide network measures for regional planning purposes.
Aimsun Online standard architecture
Dynamic traffic assignment diagram
To ensure the best possible forecasting accuracy, Aimsun Online includes a module that continuously compares forecast performances against field measurements received once the prediction period has passed. Forecasting errors give rise to alerts and also lower the confidence associated with forecasts produced during that same period. This comparison helps traffic operators to make informed decisions but also guarantees the availability of a frequently updated network and traffic representation.
The Aimsun Online package
To help you get Aimsun Online off the shelf and onto the streets, we offer a complete package that goes beyond basic product introduction, offering individual project solutions to address your specific requirements for real-time decision support. We offer:
- Off-the-shelf software
- Model setup and calibration, typically in partnership with reputable firms
- Integration with your ATMS, working closely with your systems provider
- Customisation of the web-user interface
- Training for support personnel and users
- Ongoing expert support and software maintenance