1. University of East Sarajevo, Faculty of Transport and Traffic Engineering Doboj, Lukavica, Bosnia and Herzegovina
2. Organization of African Academic Doctors (OAAD), Off Kamiti Road, P.O Box 25305-00100, Nairobi, Kenya
3. School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, China
4. Ministry of Transport, Railway Department, Yaoundé, Cameroon