1. Lead Research Engineer, National Center for Asphalt Technology, Auburn, AL 36830; formerly, Ph.D. Student, New Mexico State Univ., Las Cruces, NM 88003-8001.
2. Associate Professor, Dept. of Civil Engineering, New Mexico State Univ., Box 30001, MSC 3CE, Las Cruces, NM 88003-8001 (corresponding author).
3. Professor, Dept. of Economics and International Business, Experimental Statistics, New Mexico State Univ., Las Cruces, NM 88003-8001.