Britain joins calls for limits on truck CO2 emissions

* Emissions from trucks are not regulated in EU

* Five EU countries calling for emissions targets for trucks

* Data show trucks account for 30 pct of road transport emissions (Adds comment from industry group)

By Julia Fioretti

BRUSSELS, Sept 21 (Reuters) - Britain and three other countries have joined calls for mandatory European Union limits on the amount of CO2 pumped out by trucks, which account for 30 percent of road transport emissions but only a small fraction of vehicles on the road.

The European Commission has introduced a limit of 95 grams of CO2 per kilometre (g/km) by 2021 for cars and vans, but emissions from heavy duty vehicles (HDVs) are unregulated. The United States by contrast in June proposed tighter standards on truck emissions.

Britain, Belgium, Slovenia and the Netherlands are calling for the Commission to introduce CO2 limits for trucks, according to submissions to a Commission questionnaire, adding their weight to calls from Germany's Federal Environment Agency in August for CO2 targets for trucks.

An EU source, speaking on condition of anonymity, said Germany's backing of HDV standards was linked to efforts to protect its car industry: "There is an argument that if you bring in standards for trucks, you don't have to do any more for cars."

Lobby group the European Automobile Manufacturers' Association (ACEA) said CO2 emissions from trucks were already being reduced by efforts to improve fuel efficiency, driven by competition in the industry.

"Considering that trucks and buses come in several thousand shapes and sizes, there simply is no 'one-size-fits-all' approach to address CO2 emissions from heavy-duty vehicles," said a spokeswoman for the ACEA, whose members include Daimler AG, Renault and Volkswagen AG.

Earlier this month the European Parliament called for the development of a simulation tool measuring the fuel consumption and CO2 emissions of HDVs, and, if needed, the imposition of mandatory emissions limits.

Commission data found overall HDV emissions rose by 36 percent between 1990 and 2010, while data released on Monday by campaign group Transport & Environment show that in 2012 HDVs accounted for almost a third of road transport emissions but less than 5 percent of all vehicles on the road.

By contrast, CO2 emissions for new cars sold in the EU have fallen from more than 170 g/km in 2005 to less than 130 in 2014, although U.S. authorities have accused Volkswagen of cheating emissions tests for diesel cars.

"Lorry-makers have made no progress on fuel economy in 20 years," said Carlos Calvo Ambel, policy analyst at Transport & Environment. "This lack of progress ... (shows) manufacturers can't be trusted and that Europe needs to move ahead with CO2 standards like the U.S. and Japan." (Additional reporting by Barbara Lewis; Editing by David Holmes)