We are sad to announce that Professor Hani Mahmassani (Northwestern University) has passed away. Mahmassani will be remembered not only for his expertise in transportation science and logistics, but also for his student mentorship, important contributions to the industry, and desire for his work to positively affect as many people as possible. At IPAM, Mahmassani left a lasting impact and was regarded as a wonderful colleague and collaborator. He was a main organizer for IPAM’s long programs New Directions in Mathematical Approaches for Traffic Flow Management (2015) and Mathematical Challenges and Opportunities for Autonomous Vehicles (2020). He was also an organizer of the workshops Mathematics of Traffic Flow Modeling, Estimation and Control (2011) and Mathematical Foundations for Equity in Transportation Systems (2024), and a speaker at the Autonomous Vehicles workshop (2019).