1. Assoc. Prof. of Civ. Engrg., and Assoc. Research Engr., Inst. of Transportation and Traffic Engrg., Univ. of California, Berkeley, Calif.
2. Asst. Prof. of Civ. Engrg., Univ. of British Columbia, Vancouver, B. C., Canada
3. Asst. Prof. of Engrg., Univ. of California, Los Angeles, Calif.