Government emissions data shows that buses outside of London emit an average of 221g/km CO2e (CO2 equivalent) per passenger km compared to a small petrol car (201g/km), a small diesel car (172g/km) and a medium diesel car (215g/km). A car containing 2 people would obviously halve these figures. London buses manage 102g/km due to their higher average occupancy.
ABD Environment Spokesman Paul Biggs said: "Perhaps those who criticise lone car drivers should turn their attention to empty off-peak buses instead. Although buses provide an important public service, even London can only manage an average occupancy of around 15 passengers. Modern efficient cars outperform busses not just for CO2 emissions, but for genuine pollutants as well".
The data was compiled by DEFRA and DECC for use by employers who wish to interfere in the travel arrangements of staff.