1. Research Associate, Dept. of Transportation Planning and Engineering, National Technical Univ. of Athens, 5 Heroon Polytechniou St., GR-15773 Athens, Greece (corresponding author).
2. Ph.D. Candidate, Dept. of Transportation Planning and Engineering, National Technical Univ. of Athens, 5 Heroon Polytechniou St., GR-15773 Athens, Greece.