The two new SOR electric buses, which travel the regular BB1 and BB2 routes connecting the multifunctional BB Centrum complex and the Budějovická metro station in Prague 4, have travelled more than 23 thousand kilometres in the first half year of its full operations. More than 300 thousand passengers have caught a ride on the buses. They are the first electric buses to be put into service in the Prague mass transit system that passengers can use free of charge. The project is a joint initiative of the development and investment company PASSERINVEST GROUP, the ČEZ Group and the ARRIVA transportation company and it aims to decreased the burden on the environment, particularly in cities.