Bus lanes have been considered as effective measure to improve bus operation in metropolitan areas. Past studies on the evaluation of bus lane performance focused on its impacts on road users. Little has been done to analyze its impacts on individual bus operator. In Taipei, there are more than ten bus companies. Each has different territory and bus routes. Since bus lanes are provided on segments of eight arterial roads, the impacts on each bus company may be different . The purpose of this study is to examine the effects of bus lanes on revenue, cost and profit of each individual bus operator. This study collects historical monthly operation data of ten bus operators in Taipei. By using a time series statistical technique (ARIMA), revenue and cost of each bus operator can be projected for the scenario of no bus lanes. By comparing the projection with the actual performance with bus lanes, effects of bus lanes on revenue, cost and profit of each bus operator can be obtained. The result of this study shows that implementation of bus lanes in Taipei results in a significant increase of bus patronage by 22 million riders for the entire bus system in eleven months. Its impacts on each bus operator are different. Among the studied ten operators, five of them gained profit, while the other five underwent profit loss.