As European law makers prepare to finalise tough new legislation governing vehicle carbon emissions, fresh evidence has emerged confirming that Europe's top car manufacturers are set to fall short of proposed emission reduction targets.

According to new research from green lobby group Transport & Environment (T&E), average emissions from new cars sold in the EU last year fell fractionally from 160g/km in 2006 to 158g/km – still well short of the proposed EU target of average emissions of 130g/km by 2012.

Speaking to BusinessGreen.com, Friends of the Earth transport campaigner Tony Bosworth said that the car industry was not making progress fast enough to meet the targets. "The European Commission is proposing watering down the original 120g/km target to 130g/km," he said. "But [manufacturers] are struggling to even meet that – tough regulation is what is needed to force the pace of change."

The research revealed a mixed picture across the industry, with BMW cutting average emissions across its fleet by 7.3 per cent, compared to an average EU wide improvement of 1.7 per cent. "BMW has shown that even premium carmakers can seriously reduce CO2," said Jos Dings, director of T&E said. "But the slow response of most carmakers shows that the EU needs to keep up the pressure with challenging, long-term CO2 targets."

The push to impose stringent standards will now enter a crucial few weeks as the European Parliament's industry and environment committees meet to discuss the final version of the new rules. Late last year, the European Commission proposed watered down legislation that would not only result in the original 120g/km target being relaxed, but would also see penalties for non-compliance phased in up to 2015, effectively meaning that only the most fuel efficient vehicles would initially be covered by the standards.

"German carmakers want CO2 targets to only apply to the cleanest cars in the early years," said Dings. "It is the equivalent of demanding that a smoking ban should only apply to non-smokers."

However, Bosworth expressed hope that MEPs would resist industry lobbying and insist on tighter standards. "There is still plenty to play for," he said. "The auto industry has known these rules were coming for years, so there is no excuse for these types of low emission vehicles not being developed."