(1) The main purposes of this Chapter are—
(a) to improve public safety by decreasing risks to public safety caused by excessively loaded or excessively large heavy vehicles; and
(b) to minimise any adverse impact of excessively loaded or excessively large heavy vehicles on road infrastructure or public amenity.
(2) The purposes are achieved by—
(a) imposing mass limits for heavy vehicles, particular components of heavy vehicles, and loads on heavy vehicles; and
(b) imposing restrictions about the size of heavy vehicles and the projections of loads on heavy vehicles; and
(c) imposing requirements about securing loads on heavy vehicles; and
(d) restricting access to roads by heavy vehicles of a particular mass, size or configuration even if the vehicles comply with the mass limits, restrictions and requirements mentioned in paragraphs (a) to (c).
(3) However, this Chapter recognises that the use of particular heavy vehicles that do not comply with the mass limits, restrictions and requirements mentioned in subsection (2)(a) to (c) may be permitted on roads in particular circumstances and subject to particular conditions—
(a) to allow for—
(i) the efficient road transport of goods or passengers by heavy vehicles; or
(ii) the efficient use of large heavy vehicles that are transporting neither goods nor passengers and need to use roads for special uses; and
(b) without compromising the achievement of the purposes.