"When s. 92 speaks, as it does, of trade, commerce and
intercourse as activities among organized communities, it
quite evidently speaks of them as carried on not amidst
anarchy, but in conformity with rules. In whatever terms
it may be right to define the class of rules which is postulated,
because of the very nature of the communities the definition
must at least be wide enough to include a law of general
application limiting the permissible dimensions of the units of
traffic on the roads and wearing no other aspect than that of a
law directed to the obviating of physical damage to persons
or property. For the purpose of determining whether a law
is of such a description considerations of the need for it or of
its reasonableness may conceivably be relevant in some
circumstances.But once the description is found to apply, it cannot
matter, in my view, whether the restriction appears necessary
or reasonable, large or small, regarded either generally or in
relation to the circumstances of a particular case. For in any
event the law, because of its character, must be conceded a
place as part of the legal framework within which s. 92
contemplates inter-State trade, commerce and intercourse as
being freely carried on."