The implementation of bike sharing systems is becoming popular in the cities around the world. Bike sharing systems could be one component of public transportation systems and has the potential to solve the last mile problem in public transportation. This study demonstrates the effects of implementing a bike sharing system into public transportation systems using continuum approximation method. The implementation of bike sharing system could have various effects on user cost, agency cost and greenhouse gas emissions depending on the profile of the city in question. This study shows that implementing bike sharing systems reduce users’ opportunity cost in most cities except for small, sparsely populated, low-income cities. This study also indicates that implementing bike sharing systems sometimes increases transportation agency costs because of the additional facilities required for proper implementation. Effective policies are needed to bridge these funding gaps and realize the benefits of bike sharing for commuters in the city.