linear utility function, non-linear utility junction, and randomly distributed parameter utility function were all specified to find the effect of utility function specification on the updating of model 效用函数指定除一般常用的线性模式外,另建立旅行服务水准变数为非线性与旅行时间变数之参数为常态分配之效用函数,来探讨效用函数指定对模式更新之影响。