Man by nature mobile in pursuit of place, profession, promotion, publicity, political mileage, and pleasures. Mobility is a fundamental right. Transportation contributed to the progress of the world to a considerable extent. The world would be less exciting if there is no transportation. Transportation improves urbanization. Therefore, transportation is the driving force for the development of any nation. The performance of transportation systems can be measured through qualitative and quantitative factors. One of the essences of service quality in transportation is reliability. The causes of non-reliability in public transportation would be breakdowns, traffic congestion, and unexpected demand. Reduced breakdowns result in the reliability of transportation. The present study has been taken up to study the impact of causes for breakdowns. Four State Transport Corporations are operating in Karnataka State: KSRTC, BMTC, NWKRTC and NEKRTC. The present study found that BMTC and KSRTC had more opportunities to reduce the breakdowns. Whereas, NWKRTC and NEKRTC had moderate opportunities to reduce the breakdowns.