3a.1 University of California, School of Business Administration, Berkeley ‑ 1966, Acting Assistant Professor.
3a.2 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.
3a.3 University of Belgrade, Visiting Professor – 1970.
3a.4 University of Stellenbosch, Republic of South Africa, Visiting Professor, 1981, 1982, 1983, 1993, 1996, 2001, 2003, 2006 and 2010.
3a.5 University of Lisbon, Visiting Professor – 1988 and 1990.
3a.6 University of Sao Paulo, Brazil, Visiting Professor, 1998.
3a.7 University of Pretoria, Republic of South Africa,Visiting Professor, 2003, 2006 and 2010..
3a.8 Nanyang University, Singapore Mass Rapid Transit (SMRT) Visiting Professor of Transportation Engineering, 2004.
3a.9 Land Transport Authority Academy, Singapore, Program Leader and Lecturer of a 5-day course on Rail Transit and other Guided Systems, 2008.
3a.10 Technical University of Munich – TUM, Visiting Professor, Sep-Nov. 2009.