1. Dept. of Civil Engineering, UGent, Zwijnaarde, Belgium; Transportation Research Institute (IMOB), UHasselt, Diepenbeek, Belgium.
2. Dept. of Civil Engineering, UGent, Zwijnaarde, Belgium.
3. Transportation Research Institute (IMOB), UHasselt, Diepenbeek, Belgium.
4. Faculty of Engineering Technology, Transportation Research Institute (IMOB), UHasselt, Diepenbeek, Belgium.