The City of Montreal

Client: The City of Montreal Brief: The city’s modelling group, EMViM, needed to find an all-in-one, extensible modelling environment that would answer Montreal’s growing need for congestion management planning.

Before acquiring Aimsun, EMViM was working with a dynamic city model, MODYM, that they had built with the help of a mesoscopic tool that could show congestion and queuing. The modelling group supplemented this mesoscopic tool with several microscopic packages for analysing areas of more complex interaction. EMViM wanted to streamline this simulation platform and expand the Montreal model far beyond the size of the original in order to manage congestion and prepare for major upcoming road works.


EMViM considered many tools or combinations of tools for the expansion of the dynamic Montreal model but only Aimsun offered all three levels of modeling inside one software application: microscopic, mesoscopic and macroscopic with a single network representation and underlying database. The micro-meso hybrid capabilities of Aimsun 7 will allow EMViM to overcome mesoscopic restraints, particularly on freeway merge and diverge sections and connections to arterial networks, where modellers can simply zoom in for greater granularity.

Aimsun also fulfilled EMViM’s need for large network capabilities – an extensible mesoscopic model over eight times the size of the current version that could cover the entire island of Montreal and keep on growing. The storage requirements associated with representing large networks can easily exceed the 4GBs imposed by 32-bit architectures, leading to the necessity of 64-bit architecture as well as multi-threading capabilities.

The number of major road infrastructures that are scheduled for renovation over the next few years means that the City of Montreal urgently needed software that could combine both planning applications (modelling steady-state behavior under recurring conditions) and operations modelling (modelling short-term capacity and demand signals at isolated incidents such as lane closures due to road works or accidents). Operations models will be particularly relevant when the construction projects get underway.


EMViM will shortly incorporate the hybrid simulator in Aimsun 7, which will mean a simple zoom in and zoom out capability will replace the tedious and error-prone manual interchanges of data between meso and micro packages using different networks and databases.

Another advantage is that integrated software is reducing the high cost and management burden of using several different software tools. In the past, ENViM was maintaining four or more different types of software, which had become both technically and administratively challenging. This streamlining is closely related to the important issue of the retention of expertise: turnover of personnel is less of an issue when only one or two software tools are involved as opposed to four or five.