1. Faculty of Geo-information Science and Earth Observation (ITC); of the University of Twente; P.O. Box 6, 99 Hengelosestraat 7500 AA Enschede The Netherlands
2. The Ethiopian Roads Authority (ERA); P.O. Box 7129 Addis Ababa Ethiopia
3. Addis Ababa Univ. (AAU); Faculty of Technology, Dep. of Civil Engineering; P.O. Box 385 Addis Ababa Ethiopia