Volvo VNL 780 Operator's Manual page 308

298 OPERATION
External Environment
Under unfavorable conditions, the external environment can have a negative effect on fuel
consumption. This can be broken down into two main groups: weather and wind, and the
nature of the roads. Rain, snow, icy conditions and headwinds have a large negative impact
on fuel economy, as do hilly roads and uneven road surfaces.
Headwinds
Headwinds have a large negative impact on fuel consumption. With tailwinds, fuel saving is
only marginal.
A good sign of an axle or wheel out of alignment is uneven tire wear. Check the tires often.
Air Temperature
Low ambient temperature contributes to increased fuel consumption.
Rain, Snow and Road Surface
A wet road surface increases rolling resistance and, thereby, fuel consumption. Slush will
increase consumption even more. In certain cases, the surface structure of the road can also
have a negative effect on fuel consumption.
Gradients
A hilly road with many bends demands a higher output from the engine. The difference
between flat, straight roads and hilly, winding roads can amount to as much as a 50 percent
increase in fuel consumption.
When choosing your route, avoid hills, rough roads and frequent stops.