AirTrafcSim: An open-source web-based air trafc simulation platform. Ka Yiu Hui 1 , Chris HC. Nguyen 1 , Go Nam Lui 1¶ , and Rhea P. Liem 1¶ 1 Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR ¶ Corresponding author DOI: 10.21105/joss.04916 Software • Review • Repository • Archive Editor: Aoife Hughes Reviewers: • @gmingas • @xoolive Submitted: 17 October 2022 Published: 22 June 2023 License Authors of papers retain copyright and release the work under a Creative Commons Attribution 4.0 International License (CC BY 4.0). Statement of need Air trafc management (ATM) research traditionally focuses on the macroscopic aspect of air transportation such as airspace design, trafc fow management, airport planning and scheduling, and more (Wu & Caves, 2002). Recently, with the new development of aerial vehicle concepts, including urban air mobility (UAM) and unmanned aircraft system (UAS), there has been a growing interest in performing ATM research, for example, confict resolution using reinforcement learning (Wang et al., 2022), 4D-trajectory optimization (Tian et al., 2020), and even unmanned trafc management (UTM). Eurocontrol U-space (Barrado et al., 2020) and FAA/NASA UTM project (Kopardekar et al., 2016) are some examples of existing eforts in the industry to perform such research. To facilitate microscopic ATM research, an agent-based simulation and visualization software is needed. However, most ATM simulation tools are commercial products aimed at training air trafc controllers and airspace planning. ATM simulation tools for research purposes that are easily accessible and open-source, such as BlueSky (Hoekstra & Ellerbroek, 2016), are still scarce. In addition, the weather impact study in air transportation is mostly location dependent, such that the weather infuence factors difer for diferent climate conditions (Lui et al., 2022). Therefore, we developed AirTrafcSim to assist researchers to perform ATM research with an easy-to-use and comprehensive software environment to simulate air trafc movement and visualize the results. Compared to existing solutions, AirTrafcSim provides weather integration, a modern UI, and an easy-to-use API to control the aircraft with external modules. It is an open-source package that welcomes everyone to access and contribute. Summary Figure 1: Architecture of AirTrafcSim. Hui et al. (2023). AirTrafcSim: An open-source web-based air trafc simulation platform. Journal of Open Source Software, 8 (86), 4916. https://doi.org/10.21105/joss.04916. 1