Transportation Analysis and Simulation System (TRANSIMS) software was developed with the goal of providing state transportation agencies and metropolitan planning organizations a tool that would capture both the complex nature of individual traveler activity and the collective interaction of these activities within the transportation system.

Researchers at the Los Alamos National Laboratory (LANL) developed the original TRANSIMS methods and software. The software was initially made available to non-commercial users under a “University” license. Versions of TRANSIMS that descended from this version were independently developed at a number of academic and research institutions. A parallel commercialization effort by LANL led to a version available under a commercial license from Price Waterhouse Coopers (PWC), an effort later taken over by International Business Machines (IBM).

In 2006, LANL and FHWA released a version of TRANSIMS descended from a LANL-developed version (Version 3.1.1), further developed by researchers at the Virginia Bioinformatics Institute (Version 3.2.2) and AECOM (Version 4.0) as part of a case study based on the Washington DC metropolitan area. These versions were released under the NASA Open Source Agreement Version 1.3 to make it available as an on-going public resource. Version 4.0 provides the root version of the software for the TRANSIMS open source community. Open source community members (funded by FHWA and non-FHWA sources) have continued to refine and improve TRANSIMS code, methods and documentation based on this root version.