18. Where 2 axles or more are placed on the same transversal axis, they are considered to be a single axle.
However, in the case of a combination of road vehicles, a trailer with single wheels is deemed:
(1) to have only 1 axle when it has 2 or more axles if the distance between the centres of the outermost axles does not exceed 1 m;
(2) to have only 2 axles when it has 3 or more axles if the distance between the centres of the 2 outermost axles exceeds 1 m but is less than 2.40 m.