4. Ordinary speed limits.
(1) The Minister may make regulations prescribing a speed limit ("ordinary speed limit") in respect of all public roads, or all public roads with such exceptions as may be specified in the regulations, for any class of vehicle.
(2) Regulations under this section may prescribe different speed limits for any class of vehicle using particular categories of public roads.
(3) Regulations under this section may make provision for the exemption of a class or classes, including a sub class, of vehicles from a speed limit specified in any such regulations.