It is a special kind of environmental campaign: it is the first time that an urban bus fleet of Mercedes-Benz Citaro buses is being "retrofitted" on a large scale in Germany with the Blue Angel label of environmental quality. Just recently Michael Korwisi, Lord Mayor of the city of Bad Homburg, along with Dr. Rademacher and Andreas Vetter, both general managers at the Mittelhessen GmbH transportation company, and Randolf Troche, Head of Environmental Protection at Mercedes-Benz Mannheim, unveiled three Citaro buses with the sought-after ecolabel in Bad Homburg as a representative sample of Mittelhessen's 33 retrofitted vehicles. "The campaign, which was essentially set in motion by the city of Bad Homburg, not only exemplifies the importance of an environmentally oriented public transportation system but also visibly illustrates the environmental focus of the municipality. As a transport operator we are pleased to take on this challenge as our Mercedes-Benz fleet shows that we are dedicated to using environmental products that are truly distinguished", said Andreas Vetter. The new "angels" are operating in Oberursel and Bad Homburg transport systems.

The Blue Angel is an environmental seal of quality which has been awarded since 1978 to distinguish products and services which are particularly environmentally friendly. It is also the oldest environment-related distinction in the world for products and services. Mercedes-Benz Citaro urban buses with BlueTec® diesel technology have been eligible for the ecolabel since 1 November 2007, but a few technical requirements must first be met before the label can be awarded by the RAL e.V. and the German Federal Environment Agency. For example, the engine emissions figures must meet the Euro V or EEV standards, the internal and external noise emissions must be low, no ozone-depleting substances can be used, the refrigerant can have only a minimal potential for generating greenhouse gases and the paint finish must be free of heavy metals and have less than 130 grams of solvent per square metre. All in all these are requirements which can only be met by modern, future-oriented products which are distinguished by a high level of environmental responsibility.

The ecolabel is awarded in four categories: "Protects health", "Protects climate", "Protects water" and "Protects resources". Buses can now be awarded the Blue Angel in the "Protects health" category based on the RAL-UZ 59 requirement. The RAL-UZ 59 award requirement for low-noise and low-emission municipal vehicles and buses is focused in particular on two bases of evaluation: advantages for health and environment along with vehicles that are quiet and clean. The former evaluates noise protection in inner-urban traffic and reduced exhaust and particulate matter emissions in residential areas. Those who wish to comply with the ecolabel's requirements must permanently meet strict exhaust and particulate matter emissions standards. For vehicles that are clean and quiet, a key area of attention is the operating noise of municipal vehicles which can be especially disruptive in residential areas and quiet zones. The view of the RAL e. V. is that municipalities should operate low-noise vehicles and buses to protect residents' interests. That is why the Blue Angel also sets limits for the permissible noise level of buses.

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.