There’s been talk of this before -
here, for example.
In that thread, Harrock points out that Lancias were made left-hand drive even for the Italian market. One might also have to consider that the countries which currently drive on one side may have driven on the other in the past.
However, I wonder if there might be a technical reason arising from a drawing technique?
Hergé, and later his studio, used copious references for the vehicles in the books, yet seem to be out of step when it comes to cars.
It has also been pointed out that E.P. Jacobs has the British cars drive on the right in
The Yellow ‘M’, even after a trip to London in which he made copious reference photos, and he was no slouch in the fastidiousness department.
One that always sticks out to me is the caravan in
The Black Island, where the door is on the right hand side, opening onto the road - a British caravan like this actually should have the door on the left, so that a person wouldn’t walk into traffic.
This must have been known, as the brochure used for reference has it the correct way – and this has made me think…
In the days before digital scanning and computer graphics, and even before photocopiers, it wasn’t uncommon to use a simple glass screen to help reproduce images; one placed the image to be copied on one side of the glass, with a blank page on the other, then looking through the glass, traced the reflection where it fell on the paper. This produced an inverted image.
Only a glimmer of a theory, but I wonder if this was used in the production of so many reversed vehicles?