Aimsun (short for "Advanced Interactive Microscopic Simulator for Urban and Non-Urban Networks"[1]) is a software company that provides simulation software and services for transportation planning and traffic management.

[2] Aimsun was founded in 1997 and developed Aimsun Next traffic modeling software, which simulates mobility in networks.

[6] Aimsun was acquired by Siemens in 2018 for an undisclosed sum, as part of the Siemens Mobility Intelligent Traffic Systems (ITS) unit.

[7][8] In 2021, Siemens Mobility carved out the Intelligent Traffic Systems (ITS) unit, of which Aimsun is a part, and renamed it Yunex Traffic.

[9] In 2022, Italian infrastructure group Mundys (then known as Atlantia) bought Siemens' Yunex Traffic division for 950 million euros ($1.1 billion) to expand its transport services, making Aimsun a part of the Mundys group.