Part IV of the Principal Act is hereby amended by the insertion after section 44 of the following section:
"General speed limit.
(1) The Minister may make regulations prescribing, in respect of all public roads, or all public roads with such exceptions as may be specified in the regulations, a speed limit (which shall be known as a general speed limit) for all mechanically propelled vehicles.
(2) Regulations under this section prescribing a general speed limit may except any class of vehicles from the limit and may restrict the limit to a particular period or to particular periods."