Happy 50th Birthday AHB45 Committee on Traffic Flow Theory and Characteristics! Thanks to all of our volunteers, members, friends, paper reviewers, meeting participants, and Facebook friends! Special thanks to our past chairs Prof. Nathan Gartner and Prof. Hani Mahmassani as well as those chairs, members, friends, authors and supporters who came before. At the TRB Annual Meeting we held a celebratory workshop highlighting the past successes and future prospects of Traffic Simulation, where we also recognized the best Simulation paper for 2013; an inaugural workshop on Crowd Flow Dynamics, Modeling and Management; we held a celebratory podium session on 50 Years of Traffic Flow Theory: Achievements and Challenges, with four excellent presentations, the Greenshields Prize, the Highest Cited Paper Award, and birthday cake; we held our annual committee business meeting where we recognized new Emeritus Member Alex Skabardonis and past chair Nathan Gartner, founder of the Greenshields Prize; four other lectern sessions and five poster sessions. It has been my privilege to serve as chair of the committee since 2009, and I am proud of all of our accomplishments. We have a great circle of people who are wonderful friends and colleagues and I look forward to the next 50 years of collaboration and success!
