Having previously served as Executive Director of the Diesel Technology Forum since its founding in 2000, in October 2023 Allen led the organization to expand its scope and emerge as the Engine Technology Forum. The Forum’s work focuses on the current and future roles, and sustainability of advanced internal combustion engines in a wide range of applications including power generation commercial vehicles, marine, rail, construction, and other industrial applications. He has more than 35 years of experience working on climate, energy, environmental, public health related issues and policy. Previously he served as Vice President at Rowan and Blewitt, a public relations agency and brand of Weber Shandwick. Prior to that, he was Vice President of Environmental Policy at the American Trucking Associations (ATA), where he represented the trucking industry on legislative and regulatory policy matters at the national level including the Clean Air Act Amendments of 1990. He also was principal environmental and energy advisor to a research foundation and 60 affiliates at the state and regional levels. His prior experience included time as senior research specialist for a pharmaceutical and medical device manufacturer, conducting clinical trials in a pulmonary clinical research laboratory and as a respiratory therapist at a community hospital. He was appointed and served on EPA’s Federal Advisory Committee Subcommittee on Ozone, Particulate Matter and Regional Haze and the Clean Diesel Workgroup of the Mobile Source Technical Review Committee. A Maryland native, Schaeffer holds a Bachelor of Science degree in Zoology from the University of Maryland College Park and a Master of Environmental Health Sciences degree from Johns Hopkins University Bloomberg School of Public Health in Baltimore.