1. Department of Transportation and Logistics Engineering, Hanyang University at Ansan, 1271, Sa-3 Dong, Sangnokgu, Ansan-Si, Kyunggi-Do 426-791, South Korea.
2. Center for Intelligent Transport Systems, Korea Transport Institute, 1160 Simindae-Ro, Ilsanseogu, Koyang City, Kyunggi-Do 411-701, South Korea.