1. Mack-Blackwell Transportation Center, University of Arkansas, 4190 Bell, Fayetteville, Ark. 72701
2. Bureau of Business and Economic Research, University of Arkansas, Business Administration 443, Fayetteville, Ark. 72701
3. Industrial Engineering Department, University of Arkansas, 4207 Bell, Fayetteville, Ark. 72701
4. Civil Engineering Department, University of Arkansas, 4190 Bell, Fayetteville, Ark. 72701