Intelligent Transportation Systems (ITS) refers to transportation systems which apply emerging hard and soft information systems technologies to address and alleviate ( 缓解 ) transportation congestion problems. For example, using advanced surveillance ( 监视 ) systems, the early stages of a traffic bottleneck situation can be detected, and traffic can then be directed to other routes to mitigate ( 减轻 ) the congestion and to provide faster and more efficient routes for travelers. New technologies enable this type of surveillance and guidance response to occur in real time, and therefore, to allow potential congestion situations to be addressed before they develop into serious traffic jams.