BRUSSELS (Reuters) - The European Commission is to propose making cars, trucks, buses and vans pay higher road toll charges the more CO2 they emit as it seeks to cut road transport’s carbon footprint, two EU officials said.

FILE PHOTO: Trucks pass through an electronic toll gate on the A10 highway south of Berlin February 26, 2015. REUTERS/Fabrizio Bensch/File Photo

The proposal, which has not yet been finalised, will for the first time set some EU-wide principles for road tolls for cars, including one that motorists must pay according to the distance traveled, and include buses and coaches, the people said.

The proposal will keep the average level of tolls collected roughly constant, meaning more polluting vehicles will pay more while cleaner ones will pay less, one of the sources said.

Heavy duty vehicles (HDVs) account for a small fraction of vehicles on the road but are responsible for a third of road transport’s CO2 emissions in the EU.

The European Automobile Manufacturers Association (ACEA) - which includes Volvo, CNH Industrial’s IVECO [IVEC.UL] and Daimler - said it supported differentiating road charging according to CO2 emissions as long as it promoted low emissions in real conditions of use and provided fair competition between types of vehicles.

“Any road charges that do not consider the real emissions or the complete vehicle combination (including tyres, weight and aerodynamics) would sub-optimize the fleet,” ACEA said.

Differentiating the amount trucks have to pay according to their CO2 emissions should make road hauliers more efficient as it increases the cost of driving per kilometer and could encourage the renewal of fleets.

Currently, the EU has a legal framework governing charging for trucks, but road tolls for private vehicles are left to national governments.

The proposal will not force countries to introduce road charging schemes for cars or trucks, but will lay down rules any such scheme would have to respect were it to be introduced, the sources said.

Road tolls often prove sensitive political issues and the EU’s move to set rules on car charging and phase out time-based charging systems is likely to face opposition from both motorists and governments.

Germany, which for years was embroiled in a tussle with the EU over its proposed road toll which Brussels said discriminated against foreign drivers, only recently introduced changes to assuage the EU’s concerns.

Time-based charging systems - where motorists buy a pass lasting a certain amount of time - known as vignettes, will need to be phased out, the sources said, meaning that road tolls such as those in Germany will need to be amended if the proposal becomes law.

Hauliers oppose the phasing out of vignettes as they are cheaper to operate and the introduction of distance-based charging would require them to invest in more expensive onboard devices.

While steering clear of requiring governments to earmark the money earned from road charging for road infrastructure, the Commission plans to introduce disclosure requirements on where the revenues go.

The proposals are expected to be published on May 31, after which they will need the approval of the European Parliament and of member states.