Making right decisions in cities depends on profound investigation of conflicting objectives in planning e.g. better usage of the equipment versus better public transportation services, more facilities for travelers versus higher costs and eventually higher income versus higher taxes and fees. Thus, in order to get the best out of available resources and allocated budget it seems necessary to monitor the performance of bus transportation system as the most important civic transportation services. Bus transportation system in Isfahan plays a special role in traveler’s transition due to the weakness of other public transportation sectors like subway- which is in service just for one path. Considering the importance of bus transportation system for city decision makers and in order to improve travelers’ satisfaction, performance evaluation is a must. In this study effectiveness scores of different paths were given using data mining analysis in two different perspectives: commuters and bus transportation organization. Then, using Boot Strap method statistical approximation of the result and ranking of paths were performed. Moreover, with fitting of efficiency scores on environmental causes, effect of these causes on scores of different paths was investigated. Finally, in order to specify the quality of service in Isfahan bus transportation service, the concept of Service Level which is mentioned in TCRP 100 report was applied. Results show that the average of efficiency of bus transportation system in Isfahan is 71% and 85% from the perspective of bus transportation organization and travelers respectively. This can show that bus transportation system should increase the service around 29% to achieve an efficient level. Furthermore, it was found that private bus transportation organization used their resources optimally while state bus paths have better services. in bus organisation opinion,the 68th line has the first rank, and the 65th line is the last one with 15% efficient. also in passengers opinion the 61st bus line, hs the first rank, and 10th line is the last with 53%efficiency. On the influence of environmental effects, the cause of Speed has a direct and meaningful relation to effectiveness of bus transportation paths. Moreover, the difference in the time of travel between bus and personal cars is influential on effectiveness. In the Service Level indicator in parameters of service availability, time difference between public and personal commutes and area coverage the paths majorly stand on C level, in load coefficient parameter they stand on D level and in head distance parameter they step up to level B.