Having never used Domestic hours in their current form, this is taken from Section 96 of the 1968 Transport Act which covers them even in 2012. Maybe someone can make sense of them. I canât 
Section 96. Permitted driving time and periods of duty.
(1)Subject to the provisions of this section, a driver shall not on any working day drive a vehicle or vehicles to which this Part of this Act applies for periods amounting in the aggregate to more than ten hours.
(2)Subject to the provisions of this section, if on any working day a driver has been on duty for a period of, or for periods amounting in the aggregate to, five and a half hours andâ
(a)there has not been during that period, or during or between any of those periods, an interval of not less than half an hour in which he was able to obtain rest and refreshment; and
(b)the end of that period, or of the last of those periods, does not mark the end of that working day,
there shall at the end of that period, or of the last of those periods, be such an interval as aforesaid.
(3)Subject to the provisions of this section, the working day of a driverâ
(a)except where paragraph (b) or (c) of this subsection applies, shall not exceed eleven hours;
(b)if during that day he is off duty for a period which is, or periods which taken together are, not less than the time by which his working day exceeds eleven hours, shall not exceed twelve and a half hours;
(c)if during that dayâ
(i)all the time when he is driving vehicles to which this Part of this Act applies is spent in driving one or more express carriages or contract carriages; and
(ii)he is able for a period of not less than four hours to obtain rest and refreshment,
shall not exceed fourteen hours.
(4)Subject to the provision of this section, there shall be, between any two successive working days of a driver, an interval for rest whichâ
(a)subject to paragraph (b) of this subsection, shall not be of less than eleven hours;
(b)if during both those days all or the greater part of the time when he is driving vehicles to which this Part of this Act applies is spent in driving one or more passenger vehicles, may, on one occasion in each working week, be of less than eleven hours but not of less than nine and a half hours;
and for the purposes of this Part of this Act a period of time shall not be treated, in the case of an employee-driver, as not being an interval for rest by reason only that he may be called upon to report for duty if required.
(5)Subject to the provisions of this section a driver shall not be on duty in any working week for periods amounting in the aggregate to more than sixty hours.
(6)Subject to the provisions of this section, there shall be, in the case of each working week of a driver, a period of not less than twenty-four hours for which he is off duty, being a period either falling wholly in that week or beginning in that week and ending in the next week; butâ
(a)where the requirements of the foregoing provisions of this subsection have been satisfied in the case of any week by reference to a period ending in the next week, no part of that period (except any part after the expiration of the first twenty-four hours of it) shall be taken into account for the purpose of satisfying those requirements in the case of the next week; and
(b)those requirements need not be satisfied in the case of any working week of a driver who on each working day falling wholly or partly in that week drives one or more stage carriages if that week is immediately preceded by a week in the case of which those requirements have been satisfied as respects that driver or during which he has not at any time been on duty.
(7)If in the case of the working week of any driver the following requirement is satisfied, that is to say, that, in each of the periods of twenty-four hours beginning at midnight which make up that week, the driver does not drive a vehicle to which this Part of this Act applies for a period of, or periods amounting in the aggregate to, more than four hours, the foregoing provisions of this section shall not apply to him in that week, except that the provisions of subsections (1), (2) and (3) shall nevertheless have effect in relation to the whole of any working day falling partly in that week and partly in a working week in the case of which that requirement is not satisfied.
(8)If on any working day a driver does not drive any vehicle to which this Part of this Act appliesâ
(a)subsections (2) and (3) of this section shall not apply to that day, and
(b)the period or periods of duty attributable to that day for the purposes of subsection (5) of this section shall, if amounting to more than eleven hours, be treated as amounting to eleven hours only.
(9)For the purposes of subsections (1) and (7) of this section no account shall be taken of any time spent driving a vehicle elsewhere than on a road if the vehicle is being so driven in the course of operations of agriculture or forestry.
For the purposes of subsections (1) and (7) of section 96 no account shall be taken of any time spent in driving a goods vehicle elsewhere than on a road if the vehicle is being so driven in the course of [F2operations of quarrying or of] carrying out any work in the construction, reconstruction, alteration, extension or maintenance of, or of a part of, a building, or of any other fixed works of construction or civil engineering (including works for the construction, improvement or maintenance of a road) and, for the purposes of this exemption where the vehicle is being driven on, or on a part of a road in the course of carrying out any work for the improvement or maintenance of, or of that part of, that road, it shall be treated as if it were being driven elsewhere than on a road.]
(10)For the purpose of enabling drivers to deal with cases of emergency or otherwise to meet a special need, the Minister may by regulationsâ
(a)create exemptions from all or any of the requirements of subsections (1) to (6) of this section in such cases and subject to such conditions as may be specified in the regulations;
(b)empower the traffic [F3commissioner] for any area, subject to the provisions of the regulationsâ
(i)to dispense with the observance of all or any of those requirements (either generally or in such circumstances or to such extent as the [F3commissioner thinks] fit) in any particular case for which provision is not made under paragraph (a) of this subsection;
(ii)to grant a certificate (which, for the purposes of any proceedings under this Part of this Act, shall be conclusive evidence of the facts therein stated) that any particular case falls or fell within any exemption created under the said paragraph (a);
and regulations under this subsection may enable any dispensation under paragraph (b)(i) of this subsection to be granted retrospectively and provide for a document purporting to be a certificate granted by virtue of paragraph (b)(ii) of this subsection to be accepted in evidence without further proof.
(11)If any of the requirements of [F4the domestic driversâ hours code], is contravened in the case of any driverâ
(a)that driver; and
(b)any other person (being that driverâs employer or a person to whose orders that driver was subject) who caused or permitted the contravention,
shall be liable on summary conviction to a fine not exceeding [F5level 4 on the standard scale]; but a person shall not be liable to be convicted under this subsection if he proved to the courtâ
(i)that the contravention was due to unavoidable delay in the completion of a journey arising out of circumstances which he could not reasonably have foreseen; or
(ii)in the case of a person charged under paragraph (b) of this subsection, that the contravention was due to the fact that the driver had for any particular period or periods driven or been on duty otherwise than in the employment of that person or, as the case may be, otherwise than in the employment in which he is subject to the orders of that person, and that the person charged was not, and could not reasonably have become, aware of that fact.
[F6(11A)Where, in the case of a driver F7 of a motor vehicle, there is in Great Britain a contravention of any requirement of [F8the applicable Community rules] as to periods of driving, or distance driven, or periods on or off duty, then the offender and any other person (being the offenderâs employer or a person to whose orders the offender was subject) who caused or permitted the contravention shall be liable on summary conviction to a fine not exceeding [F5level 4 on the standard scale]]
[F9(11B)But a person shall not be liable to be convicted under subsection (11A) ifâ
(a)he proves the matters specified in paragraph (i) of subsection (11); or
(b)being charged as the offenderâs employer or a person to whose orders the offender was subject, he proves the matters specified in paragraph (ii) of that subsection]
(12)The Minister may by orderâ
(a)direct that subsection (1) of this section shall have effect with the substitution for the reference to ten hours of a reference to nine hours, either generally or with such exceptions as may be specified in the order;
(b)direct that paragraph (a) of subsection (3) of this section shall have effect with the substitution for the reference to eleven hours of a reference to any shorter period, or remove, modify or add to the provisions of that subsection containing exceptions to the said paragraph (a);
(c)remove, modify or add to any of the requirements of subsections (2), (4), (5) or (6) of this section or any of the exemptions provided for by subsections (7), (8) and (9) thereof;
and any order under this subsection may contain such transitional and supplementary provisions as the Minister thinks necessary or expedient, including provisions amending any definition in section 103 of this Act which is relevant to any of the provisions affected by the order.
[F10(13)In this Part of this Act âthe domestic driverâs hours codeâ means the provisions of subsections (1) to (6) of this section as for the time being in force (and, in particular, as modified, added to or substituted by or under any instrument in force under section 95(1) of this Act or subsection (10) or (12) of this section)]
