1. Ph.D. Candidate, Dept. of Transportation Planning and Engineering, School of Civil Engineering, National Technical Univ. of Athens, Zografou Campus, Athens, Greece 15773.
2. Assistant Professor, Dept. of Transportation Planning and Engineering, School of Civil Engineering, National Technical Univ. of Athens, Zografou Campus, Athens, Greece 15773 (corresponding author).
3. Research Associate, Dept. of Transportation Planning and Engineering, School of Civil Engineering, National Technical Univ. of Athens, Zografou Campus, Athens, Greece 15773.