Sitras MES marks a further step towards greater environmental compatibility and economic efficiency in mass transit. Sitras MES enables the energy generated during braking to be stored on board the vehicle. This energy is then used when the vehicle reaccelerates, thereby reducing the load on the traction power supply, stabilizing the line voltage and minimizing the use of expensive peak power. The vehicle is therefore able to cut its primary energy import by as much as 30%. For example, a triple-articulated Combino Plus tram can thereby reduce its CO₂ emissions by 50 tons a year. Sitras MES also allows vehicles to operate without an overhead contact line. This has a positive effect on cityscapes in that, for example, transit vehicles can now cross picturesque city squares free from contact wires and catenaries or travel underneath structures where overhead lines cannot be installed.

Sitras MES also improves the energy-saving advantage of diesel-electric drives. The system stores the energy released during braking and makes it available again during acceleration. This allows the diesel engine to always run in an optimum and economical speed range. Alternatively, Sitras MES acts as an energy source, such as during short stops at signals. This reduces noise emissions and fuel consumption and thus CO₂ and NO_x emissions.