This paper extend j ? rgensen ’ s transport model by considering the influence of the number of passengers on travel time costs , and use the method of comparative statics analysis to discuss how travel distance affects the fare levels and the quality of transport supply . and it concludes some sufficient conditions to ensure optimal fare and optimal quality will increase when the travel distance becomes longer Rgensen的交通模型,利用比较静态分析的方法讨论了出行乘距对票价和供给服务质量水平的影响,给出了一个新的保证最优票价和最优供给服务质量水平会随着出行乘距增加而增加的充分条件。