There are two characteristics common to most of these papers: they are based on Wardrop's principle and they are travel time crisp.observed that ‘in real world, however, the driver can only use fuzzy traffic information even if several types of information are available’. These authors succeeded in formulating the fuzzy user equilibrium with fuzzy travel time. They confirmed their assumption about drivers' perception of time as triangular fuzzy numbers by organizing the survey on the network comprised of Hanshin Expressway and urban streets in the Osaka area. In their paper, the authors introduced ‘the descriptive method of route choice behavior to design the traffic assignment model’. They showed that ‘the state of user equilibrium is also generated even if fuzziness of travel time exists’. Akiyama et al. developed Fuzzified Frank-Wolfe algorithm to solve the problem considered. This pioneer paper undoubtedly presents a significant study on the relationship between traffic information and drivers' behavior.