Parisian public transport company RATP is using a Gruau Microbus fitted with the StARS + X system on the “Bièvre-Montsouris” local service. This experiment, the result of a research partnership between the RATP, Valeo and the manufacturer Gruau, was selected and approved by ANR (French National Agency for Research) and PREDIT (French Program for Transport Research) in 2006, with the financial support of ADEME as part of the national “clean and cost-cutting vehicles” program.

In heavy urban traffic, the combined start-stop and regenerative braking system can generate fuel savings up to 20%, according to Valeo.

The regenerative braking extension to the StARS start-stop system uses supercapacitors for energy storage.