In C&U regulations, the area in which minimum ground clearance for trailers is measured (i.e. on single axle semi-trailers, between the point of support at forward end and the centre of axle on semi-trailer; on multi-axle semi-trailers, between point of support at forward end to midway between centres of the foremost and rearmost semi-trailer axles – in the case of other trailers measured from centre of front axle or midway between such axles and midway between rear axles).