COMPRO is coordinated by ISIS –Institute of Studies for the Integration of System. The core partnership includes both local and regional authorities and public transport operators:

Two major factors strongly influenced the willingness of the urban area to develop a large-scale policy of non-polluting public transport fleet: the implementation of the first tramline in 1985 and the experimentation of CNG buses within the Jupiter 2 project.
Moreover, opinion polls conducted on public transport perception showed that it was necessary to enhance the image of buses, which had been left behind in comparison with the modern tram.
By a convention signed in 2000, Nantes Métropole Urban Council mandated Semitan (PT operator) to conduct a bus fleet procurement programme for the three-year period 2001-2003. As a minimum, the specifications of the new buses had the same ones as those of standard diesel buses already operating on the network.
Following the call for tender, 125 Heuliez GX317 GNV standard buses and 30 Volvo
7000 GNV articulated buses were delivered, all operating by the end of 2003.
Some deviation occurred in this delivery and operating schedule, due to homologation, ratification, and operational problems. Despite these problems, Nantes Métropole decided in June 2005 to continue to purchase new CNG buses. 60 new CNG buses will be purchased between 2006 and 2008.

 In order to reduce traffic air pollution, the Emilia Romagna Region allocates incentives to local public transport (LPT) either by contributing to the bus fleet renewal or supporting researches, meetings and agreements. For this purpose the Region works together with national and regional research institutes such as Enea, Cnr, Arpa, etc…,with the Ministry of Infrastructures and Transport, the regional air, noise and elettromagnetic pollution department, local authorities, local mobility agencies and LTP regional companies.
Emilia Romagna’s strategy aims on one side at progressively creating local public transport fleets made up of eco-compatible vehicles, and on the other side – in relationship to urban areas – at supporting  modal interchange and traffic fluidification  on the main access roads to towns centres (by means of reserved bus lanes and telecontrol systems).
The low impact technologies on which Emilia Romagna is mainly engaged are CNG, electric, and hybrid vehicles. The Agency is also interested in researches on the use of hydrogen as energy carrier.

As far as CNG vehicles are concerned Emilia Romagna ha promoted the implementation of new depots and refuelling stations in compliance with regulations and according to local needs. The results so far are very good, particularly in Bologna, since the number of circulating CNG buses is very high and two new refuelling stations are under construction.
With reference to electric and hybrid vehicles, Emilia Romagna has promoted them first of all in urban areas since they help to decrease noise and air pollution (particulate). Emissions of polluting gases due to the production of electricity can be better monitored and reduced directly at the power stations by means of filters.
Emilia Romagna allocates also incentives to support the purchase of new diesel buses which are equipped with antiparticulate filters.
Finally, in partnership with researchers and development institutes and with private companies which produce hydrogen Emilia Romagna is committed to evaluate the technical/economic feasibility  and the time needed for a real implementation of this technology on buses fleets.

The city of Göteborg has a long standing tradition in clean vehicles which recently was boosted by the participation to CIVITAS. Here, the city and three local companies (DHL, GreenCargo AB, Gatubolaget) purchased CNG heavy duty vehicles to be destined to local freight distribution (within the local environmental zone). The result so far has been 1 new fuelling station, 16 new distribution vehicles and 2 heavy duty vehicles. These small figure are complemented by greater new acquisitions both in private fleets and in the context of the current biogas investments (EU Project BiogasMax). Göteborg is an example showing that actors belonging to different part of the transport chain can cooperate toward the attainment of a switch from conventional vehicles to clean vehicles.

Bremen has been actively involved in developing the draft of the Directive for Clean Vehicles and is explicitly mentioned in the paper (page 7) – as contributing to the “Stakeholder Forum” of DG TREN.
Bremen takes the task of the Air Quality Directives very serious. The already for a long period taken measurements of air quality showed in the field of PM10 two hotspots – and at least one hotspot will exceed the limit of NO2 in 2010 – if not further measures will be taken. With its integrated transport strategy, Bremen is creating further incentives for the use of sustainable modes – especially for the use of the bicycle, which is considered as ultimate zero-emission vehicle.
In its air quality management plan and the action plan, Bremen had already implemented a “clean zone”, where all Light and Heavy Duty Vehicles (> 3.5 tons) are banned – except fulfilling Euro IV or better. This shall give an incentive to purchase quickly low-emission vehicles.
Bremen has extended in the last years its tram network. Now on several lines, trams have taken over the services of buses. This has reduced directly the emission level along these corridors and at the same time has attracted an increasing number of passengers.
There are some remaining inner-city bus lines, where the emission standard shall be drastically updated. The latest purchase of buses (articulated) has been updated to EEV-standard. Bremen is the first German city with regular EEV-Diesel busses.
But Bremen sees also the ecological and economical need to reduce energy consumption and greenhouse gases. Therefore, the various market options will be studied to select an ecological sound and economically reasonable propulsion for the next generation of busses for the Bremen PT operator BSAG. Until 2010, it is considered to purchase  hybrid busses.
Bremen has signed the commitment to reduce CO2-emissions. This project may contribute by developing a better market for less CO2-emitting busses – and their purchase under market conditions for Bremen.
The key alternatives to reduce the consumption of mineral oil have been seen under the given conditions of Bremen:

For both alternatives, there are still very relevant additional costs, which can be reduced by economy-of-scale by developing joint market demand with other cities and PT operators. In economic terms, any solution will have to be economically comparable in operation costs to Diesel busses with special motor-management and after treatment fulfilling EEV standard. That high level of commitment will have to be kept also with potential joint procurement of busses with alternative propulsion.