(1) Each of the following periods or series of periods of driving shall be deemed to be an excessive period for the purposes of this section, that is to say: -
(a) any continuous period of driving exceeding five and one-half hours;
(b) any series of continuous periods of driving amounting in the aggregate to more than eleven hours in any period of twenty-four hours beginning two hours after midnight;
(c) any period or series of periods of driving so arranged that the driver has not at least ten consecutive hours for rest in every period of twenty-four hours beginning at the commencement of any period of driving.
(2) For the purposes of the next preceding sub-section of this section -
(a) where a driver has at least nine consecutive hours for rest in a period of twenty-four hours beginning at the commencement of a period of driving, such period of at least nine consecutive hours shall be reckoned as a period of ten consecutive hours if such driver has at least twelve consecutive ho