Hamburg and affiliates have recently bought Volvo hybrid buses. When I visited the area recently there were by coincidence eight of the buses standing in the court of the Volvo workshop in Hamburg.
The transport authority, Hamburger Hochbahn, is probably the most reputed transport authority in Europe. The track record is impressive with increased attractiveness, an increasing share of public transport users and at the same time with enormous efficiency. A bit more than 50% of the daily users choose public transports. The cost coverage in 2011 was 88.7%.
No doubt both cost efficiency and attractiveness were important factors in the decision to purchase Volvo hybrid buses.