The Blue Angel is an environmental policy tool which is in line with the market and can be voluntary used to label products with their positive features. The 33 Citaro buses with the Blue Angel label must meet the award criteria for the RAL-UZ 59 ecolabel for the entire time that the label is in use. That precludes for example changes made to the engine characteristics which could result in non-compliance with Euro V/EEV emissions figures, changes of any kind which would mean exceeding the noise limits for low-noise vehicles, installing add-ons which contain ozone-depleting substances or applying additional paintwork containing heavy metals. Compliance with the criteria must be guaranteed by the transport operator, Mittelhessen GmbH.
Since 2006 the transportation company Mittelhessen GmbH (VM) has been serving the public transport system in the districts of Limburg-Weilburg, Marburg-Biedenkopf, Lahn-Dill as well as in the Hochtaunus, Rheingau, Taunus and Wetterau districts. As a wholly owned subsidiary of Abellio GmbH, the company, which is based in Weilburg, Germany, currently operates 244 vehicles and employs 395 staff. The total distance of 10 million kilometres that it logs each year are all within the area covered by the Rhein-Main-Verkehrsverbund (RMV). The service lines in Bad Homburg and Oberursel operate a total of 45 buses.