[jbothma]

The whole article seems full of conjecture and generalisation.

A big example:

> Another advantage of a conventional cab design is that the truck can be more economical. Surely they usually pull heavier loads, but if there were two trucks, one a cab-over and another one a conventional cab design, and they had the same powertrain and the same cargo, the conventional cab truck would most likely use less fuel. Of course, that is just in theory – in reality there are too many factors to consider.

I don't know... power, load and fuel economy is the kind of data that's extremely available about motor vehicles... this is something we can't figure out? Or were they just writing hearsay to push content and get clicks? ("Subscribe to our facebook. Loads of content coming soon!")

[tgtweak]

Lots of conjecture. The reality is most of the drag is encountered on the trailer, tires and underside. This is the reason you now see "skirts" on almost all trailers, and the general reduction in distance between tractor and trailer and not long airplane-like tractors.

More important to fuel economy is maximizing cargo per trip, as having 20% more cargo in the trailer has no impact on aerodynamics and minimal contribution to rolling resistance and acceleration losses. This is the main argument against the length restrictions in the EU. Longer trailers + more aerodynamic tractors would lead to a significant increase in fuel economy - albeit at the cost of road safety: EU records nearly identical deaths per year for trucking related accidents as the US - around 5000 - but has 300% as many trucks on the road and 50% more population than the US.

[enragedcacti]

> Or were they just writing hearsay to push content and get clicks?

I think this is a very uncharitable interpretation. It has been decades in the US and Canada since cab overs fell out of style and thus you can't buy ones that take the same trade-offs as your average conventional truck. Comparing trucks designed for completely different regulatory, geographical, and practical constraints isn't going to net something useful so we have to make estimated guesses. It seems like it would be similar to comparing the fuel economy of an an unladen F-150 with an unladen F-350; They might do similar things but in practice there are so many capability trade-offs that it isn't a particularly interesting thing to do. As they said:

> that is just in theory – in reality there are too many factors to consider.

[zardo]

The most aerodynamic COE have higher drag coefficients than the most aerodynamic conventionals, the big flat front produces a large high pressure area.