1. Midwest Research Institute, 425 Volker Boulevard, Kansas City, MO 64110-2299
2. , 35 Merton Street, Apt. 1706, Toronto, Ontario M4S 3G4, Canada
3. Pennsylvania Transportation Institute, Transportation Research Building, Pennsylvania State University, University Park, PA 16802
4. Turner-Fairbank Highway Research Center, FHWA, 6300 Georgetown Pike, McLean, VA 22101