Careful preparation and management of the rollout proved to be the key factor to success, along with close collaboration with the manufacturer.
Compared to a vehicle of the very newest design with full air conditioning and particle filter, fuel consumption fell by approx. 18 %. Compared to a Euro 2 bus and older technology, it was down by as much as 30 % or more.
Measurements in real operation have shown that the emission values are appreciably lower than the saving in fuel. This is attributed above all to the smaller engine and its new operating concept. The level of noise developed when approaching, especially at bus stops, is viewed very positively. In order to deploy hybrid buses in a really energy-saving way, it is necessary to have precise knowledge of the route characteristics and vehicle attributes and to schedule the vehicle deployment accordingly.
During the term of the project, the vehicles proved to be far more reliable than the Stuttgart Tram Company had assumed. The hybrid buses are very well accepted by the drivers and preferred to diesel ones. This can be attributed above all to the handling qualities and reduced noise.
Maintenance of the hybrid buses is carried out within the workshop’s normal workflow. The existing personnel were trained accordingly. In future, all Stuttgart Chamber of Trade and Industry vehicle mechanic trainees will obtain the basic qualification as part of their training.