Dr. O. A. Elrahman (Sam), Ph.D. is a Senior Research Scholar at the Center for Transportation Infrastructure and Environment (CTIE), Rensselaer Polytechnic Institute. Prior to his work with the Center, Dr. Elrahman served at the New York State Department of Transportation (NYSDO) for over 30 years at different capacities/divisions, most recently, the Head of the Research Coordination and Technology Transfer group of the Transportation Research & Development Bureau. His extensive research and management activities spanned several departmental divisions, including Environmental Analysis, Policy, Transit, Project Development, and Economic Development.