- University of California, School of Business Administration, Berkeley ‑ 1966, Acting Assistant Professor.
- Founded the Program in Transportation Systems Engineering (Undergraduate and Graduate) at the University of Pennsylvania -1967.
Positions at the University of Pennsylvania: Assistant Professor – 1967; Associate Professor – 1970; Professor – 1975; UPS Foundation Professor of Transportation, Department of Systems Engineering – 1990; Professor of City and Regional Planning, 2002; Retired, 11 June 2010; Emeritus Professor, 1 July 2010.
- University of Belgrade, Visiting Professor – 1970.
- University of Stellenbosch, Republic of South Africa, Visiting Professor, 1981, 1982, 1983, 1993, 1996, 2001, 2003, 2006 and 2010.
- University of Lisbon, Visiting Professor – 1988 and 1990.
- University of Sao Paulo, Brazil, Visiting Professor, 1998.
- University of Pretoria, Republic of South Africa,Visiting Professor, 2003, 2006 and 2010..
- Nanyang University, Singapore Mass Rapid Transit (SMRT) Visiting Professor of Transportation Engineering, 2004.
- Land Transport Authority Academy, Singapore, Program Leader and Lecturer of a 5-day course on Rail Transit and other Guided Systems, 2008.
- Technical University of Munich – TUM, Visiting Professor, Sep-Nov. 2009.
3.2 Research Areas
- Urban Transportation
- Urban Transit Systems
- Traffic Engineering
- Bus, Light Rail, Metro & Regional Rail Systems
- Design of Transportation Facilities
- Comparison and Selection of Transit Modes
- Transportation Policies for Livable Cities
- Transportation Planning and Economics
- High-Speed Rail Systems
- Rail Transit Networks: Design and Operation
3.3 Courses Taught
- Transportation Systems Engineering
- Urban Transit Systems and Technology
- Cities and Transportation
- Design of Transportation Systems and Facilities
- Project Management
- Systems Engineering Senior Design
- Urban Transportation for Livable Cities