This was the warning from the Low Carbon Vehicle Partnership (LowCVP) after the Society of Motor Manufacturers and Traders (SMMT) published its latest report on CO2 emissions.
While the report showed CO2 emissions are continuing to fall, there was a slowdown in the headline rate of CO2 reduction in both cars and vans.
UK average new car CO2 fell 1.1% in 2016 versus 2015, compared with 2.6%; 2.9% and 3.6% in the previous three years.
LowCVP managing director Andy Eastlake said: “Today’s report should come as an early warning to all stakeholders that while our focus on dramatically improving the air quality in our cities is absolutely necessary, we must not take our eyes off the ball in terms of carbon reduction.
“We believe there is a like-for-like CO2 advantage in running diesel versus petrol in motorway/long-distance use. The task of transforming the diesel car fleet to deliver the low air quality emissions performance we are seeing from the latest trucks is very challenging, but in motorway operations a highly efficient combustion engine, such as diesel, is currently the lowest carbon practical solution. We need to ensure that we use the most appropriate available technology in each situation.”
The report also showed a slowdown in the growth of Alternative Fuel Vehicles (AFV) sales from 40.3% in 2015 to 22.2%.
Eastlake said: “We need to see a ramping-up in the rate of take-up in the market for plug-in cars and other low emission alternative fuel vehicles (AFVs). These are critical technologies in the transition and some of the signals, such as the VED incentive to encourage consumers to buy lower CO2 cars are being eroded with upcoming changes.”