Aerodynamic trailers, like Don-Bur's Teardrop and slope-fronted double-decks, have received a massive boost after a DfT-commissioned report suggests they offer a cost-effective way of cutting CO2 emissions. The report from consultancy Ricardo, published last week, will be used to inform the government's low carbon transport strategy and may encourage the government to incentivise the uptake of different technologies or introduce new training programmes.
Ricardo technology and clean energy manager Nick Powell explains: "We were asked to examine: if you were looking at heavy- or medium-duty vehicles, what are the most promising technologies to reduce carbon emissions and how far into the future are they likely to come?" Group technology director Neville Jackson adds: "You have to take a bigger view of it: at some point in the future there may be targets to reduce fuel consumption from this sector and it is better that these are based on fact rather than putting a finger in the air. You need to understand what's feasible before you set a target and that's what this study is about."
It grouped the various low-carbon technologies into three areas: vehicles (including aerodynamics, reduced rolling resistance tyres and driver behaviour); powertrain (engine efficiency, waste heat recovery, alternative powertrains and transmissions); and fuels (three fuels were analysed along with three methods of producing biodiesel). These were scored against a number of criteria including the potential reduction in CO2, the maturity of the technology, cost and safety.
Aerodynamic trailers and bodies scored highly, says Jackson, because a long-haul truck expends about 35% of its energy to overcome drag, therefore anything that can be done to address that achieves a relatively large improvement in fuel consumption. For instance, a 22% reduction in rolling resistance results in an 8.7% improvement in fuel consumption.
Jackson adds: "There's a long way to go with aerodynamics. Formula 1 teams employ armies of people working to improve airflow and we need to put more effort into that, just as racing does."
However, the report warns that aero trailers are not a panacea as they are not applicable to all operations. Overall, aerodynamic trailers, electric bodies (on refuse trucks or fridges, for instance), low rolling resistance tyres and platooning have the most potential for CO2 reduction among the vehicle technologies; electric drives, fuel cells and full hybrids are highlighted in the powertrain section; and biogas, biofuels and hydrogen are the fuel technologies with the greatest lifecycle CO2 benefits. However, tailpipe CO2 reductions are lower, it cautions.
Platooning: looking beyond the regulations
One area that's sure to cause controversy is the suggestion that platooning - driving a number of trucks extremely close together to ensure high aerodynamic performance - could be used in the real world. Ricardo's study suggests that platooning could cut CO2 emissions by as much as 20% at motorway speeds for a relatively minor cost increase of about £1,600 per vehicle for sensors and active safety features.
Although the technology - which sees the lead driver in a train of trucks controlling the powertrain, brakes and steering for all the vehicles in the convoy - has been proved to work in a test environment, it is not legal to use on the road. But Ricardo group technology director Neville Jackson says that with such a high potential CO2 saving it is something that should not be ruled out. "It is an important area of research because of the need to improve aerodynamics: the closer you can get to the vehicle in front the more efficient the train becomes. What you need to do is have the vehicles very, very close together, at a distance that would not be safe if it was not electronically controlled," he says.
"The guy in front is effectively driving the whole train. Regulations don't allow that, but if you want to take a step forward, then that's one way to do it. There are plenty of challenges in the way, but the potential gains are significant." Jackson says that distances between the vehicles would be less than 1m. As well as the technological and legal barriers to overcome, Jackson says there needs to be more research conducted into how the train would interact with other road users as well as practicalities such as how trucks leave or join the train.
But he adds: "If there was a policy decision to do so, then you could have something working along these lines within the next five to 10 years."