Critics are accusing the Department for Transport's appraisal method for road building schemes which measure CO2 emissions against national emissions and benefits of the road scheme against the local economy. This results in CO2 emissions having a much smaller impact on whether individual road schemes gets the 'go-ahead'. 

Professor Phil Goodwin, Fellow of CIHT, says to the BBC that the DfT should employ the same standard for measuring the negatives of the roads programme as it uses to measure the positives. He says that the appraisal system makes CO2 "uniquely unimportant". 

Chris Todd, director of the Transport Action Network, compared the appraisal system to a morbidly obese person insisting that they can gorge another cream cake, because no single cake will have material impact on their well-being. The Transport Action Network are currently seeking to take the DfT to court over the Road Investment Strategy 2 (RIS2) on the grounds of its climate impact.

A spokesperson for HM Treasury has rejected that the appraisal system is ignoring CO2 emissions, arguing that climate change is a global problem, whereas road schemes offer local benefits, hence the two should be separated. 

Further, HM Treasury rejects another claim made by Transport for Quality of Life saying that the government's road programme will increase carbon emissions from the strategic road network by about 20 metric tonnes CO2 (MtCO2) when it needs to reduce CO2 by 167 MtCO2. According to the treasury they have assessed carbon impacts using more accurate methods than those used by Transport for Quality of Life and that the new road improvements will have an impact of just 0.27 MtCO2 through to 2032. 

Source: https://www.bbc.co.uk