In addition to the significant contribution of electric vehicles to energy consumption and carbon emissions, the fact that they are quiet and highly sustainable in terms of use causes an increase in demand. Buses, which are a type of public transportation vehicle among vehicles, are of great importance for transportation, providing fuel savings for society in general and being a solution to the traffic problem. Gathering two separate phenomena such as electricity and a bus under one roof raises the impact values of the concepts to a higher level. In addition to having systemic differences, electric vehicles should be put into use in a way that is ready to provide long-term service in operating conditions, similar to conventional vehicles. To prove the readiness for use of the vehicles, they are subjected to multiple stages of testing simulating real operating conditions. At the end of the test process, if the vehicle meets the predetermined criteria, the test process is completed, and the vehicle is approved. In this study, two different battery electric bus models were subjected to road endurance tests and critical parts were determined and product reliability was ensured by making product development studies. The results of the study revealed the areas that should be considered in terms of periodic maintenance in electric vehicles.