Fuel consumption, measured in kilometres per
litre, was recorded by vehicle type (tractors and
rigids) for each fleet during the survey period.
The rate at which vehicles consume fuel is affected
by a range of factors, including:
■ the weight of vehicle and load
■ the nature of the driving conditions and the
frequency of stops
■ driving technique
■ the specification of the vehicle including
airflow management equipment
As expected, this range of factors led to a large
variation in consumption rates recorded for each
vehicle type in the different fleets. An analysis by
vehicle type is shown in Figure 9.
The range of fuel consumption for each vehicle
type gives some idea of the potential savings for
poorer performers. For example, for 40 tonne trucks
on 5 axles the range of fuel consumption was 3.1 to
3.8 kilometres per litre. For the worst performer to
match the best performer a 22.6% improvement isrequired. Travelling 100,000 kilometres per annum,
with an approximate fuel cost of 65p per litre (exVAT),
this improvement would lead to an annual
saving of approximately £4,000 per vehicle. This
corresponds to a reduction of over 15 tonnes of
CO2 emissions per vehicle per annum.
Correlating the use of airflow management
equipment, such as aerofoils, spoilers or skirts,
against the fuel consumption rates, illustrates the
benefits for all but one vehicle type, as shown in
Figure 10.