The authoritative UK Energy Research Centre (UKERC) has carried out an analysis of the impact of enforcing the current 70mph speed limit or raising the limit to 80 mph on the motorways of the UK.
Current emissions from passenger cars make up about 15% of total UK CO2 emissions. Whilst newer car technologies are more efficient at higher speeds, a medium sized family car still uses about 15% more fuel at 80mph than 70mph.
UKERC researchers Dr Jillian Anable, University of Aberdeen, and Dr Christian Brand, University of Oxford, calculate that raising the speed limit to 80mph will increase CO2 emissions from cars by almost 2% per annum, if the current enforcement policy continues.
For a more detailed summary of this UKERC work click here.