1. Professor, Dept. of Transportation Planning and Engineering, School of Civil Engineering, National Technical Univ. of Athens, Zografou Campus, 5 Iroon Polytechniou St., 15773, Greece.
2. Ph.D. and Senior Researcher, Dept. of Transportation Planning and Engineering, School of Civil Engineering, National Technical Univ. of Athens, Zografou Campus, 5 Iroon Polytechniou St., 15773, Greece (corresponding author).