Industrial machinery, whether or not it is entirely fitted with pneumatic tyres and whether or not it exceeds 8.5 tons, may be used on a road without registration if —
(a) the industrial machinery is a road roller;
(b) the road used is not maintained with public funds;
(c) the distance travelled on the road is not more than 1.5 miles; or
(d) there is a subsisting permit issued under section 33 authorizing such use.