1. Sr. Res., Hwy. Res. Inst., Korea Hwy. Corp., Sungnam, Kyunggi 461-380, Korea.
2. Dir., Inst. for Transport Technol., Univ. of Stellenbosch, Stellenbosch, South Africa, 7600.
3. Joe J. King Chair in Engrg., Dept. of Civ. Engrg., Univ. of Texas at Austin, Austin, TX.