routeing and better return loading, improve the general
productivity of road haulage operations and are seldom
justified on fuel conservation grounds alone. This article
is primarily concerned with the first category of
measures, which are specifically designed to improve fuel
efficiency. It takes the amount of lorry movement as given
and examines what can be done to reduce the associated
demand for fuel.
The hauliers surveyed were asked to rate a range of fuel
conservation measures in terms of their relative
importance (see Table II). They considered good vehicle
maintenance and driver training to be the most important
measures, each being regarded as very important by
around 60 per cent of the sample. Improved aerodynamics
and vehicle replacement policy were felt to be of moderate
importance, while there was considerable scepticism
about the value of driver incentives and speed limiters.
The environmental survey conducted by PE-International
asked a broader cross-section of British firms to
indicate what "fuel-efficiency related" policies they had
implemented[2]. This also identified preventative
maintenance as the most important measure, with 91 per
cent of firms claiming to perform it on all their vehicles.
Vehicle Maintenance
Fuel efficiency can be impaired by a wide variety of
vehicle defects. According to a study by the Freight
Transport Association (FTA) (quoted in[ll]), the most
common of these fuel-related defects are fuel leaks either
in the supply or injection systems, representing
approximately 44 per cent of the total. Tyres that are
either misaligned or under-inflated account for a further
21 per cent of fuel-related faults. A one-degree
misalignment of one of the axles on a multi-axle trailer
will raise fuel consumption by roughly 3 per cent, while a
two-degree misalignment will increase it by 8 per
cent[12]. The other major category of fuel-related faults,
constituting 17 per cent of the total, are those associated
with the engine.