All the constituent parts of the recording equipment must be made of materials with sufficient stability and mechanical strength and stable electrical and magnetic characteristics.

Any modification in a constituent part of the equipment or in the nature of the materials used for its manufacture must, before being applied in manufacture, be submitted for approval to the authority which granted type-approval for the equipment.

The range of speed measurement shall be as stated in the type-approval certificate.

The natural frequency and the damping of the measuring device must be such that the instruments showing and recording the speed can, within the range of measurement, follow acceleration changes of up to 2 m/s², within the limits of accepted tolerances.

The control of the mechanism for resetting the clock must be located inside a case containing the record sheet; each opening of that case must be automatically recorded on the record sheet.

If the forward movement mechanism of the record sheet is controlled by the clock, the period during which the latter will run correctly after being fully wound must be greater by at least 10 % than the recording period corresponding to the maximum sheet-load of the equipment.

The visual instruments of the equipment must be provided with adequate non-dazzling lighting.

For normal conditions of use, all the internal parts of the equipment must be protected against damp and dust. In addition, they must be made proof against tampering by means of casings capable of being sealed.

The value of the smallest grading on the instrument showing distance travelled must be 0,1 kilometres. Figures showing hectometres must be clearly distinguishable from those showing whole kilometres.

The figures on the distance recorder must be clearly legible and must have an apparent height of at least 4 mm.

The distance recorder must be capable of reading up to at least 99 999,9 kilometres.

Within the range of measurement, the speed scale must be uniformly graduated by 1, 2, 5 or 10 kilometres per hour. The value of a speed graduation (space between two successive marks) must not exceed 10 % of the maximum speed shown on the scale.

The range indicated beyond that measured need not be marked by figures.

The length of each space on the scale representing a speed difference of 10 kilometres per hour must not be less than 10 millimetres.

On an indicator with a needle, the distance between the needle and the instrument face must not exceed three millimetres.

All equipment, whatever the form of the record sheet (strip or disc), must be provided with a mark enabling the record sheet to be inserted correctly, in such a way as to ensure that the time shown by the clock and the time-marking on the record sheet correspond.

The mechanism moving the record sheet must be such as to ensure that the latter moves without play and can be freely inserted and removed.

For record sheets in disc form, the forward movement device must be controlled by the clock mechanism. In this case, the rotating movement of the record sheet must be continuous and uniform, with a minimum speed of seven millimetres per hour measured at the inner border of the ring marking the edge of the speed recording area. In equipment of the strip type, where the forward movement device of the record sheets is controlled by the clock mechanism, the speed of rectilinear forward movement must be at least 10 millimetres per hour.

Recording of the distance travelled, of the speed of the vehicle and of any opening of the case containing the record sheet or sheets must be automatic.

Every kilometre of distance travelled must be represented on the record by a variation of at least one millimetre on the corresponding coordinate.

Even at speeds reaching the upper limit of the range of measurement, the record of distances must still be clearly legible.

• the trace drawn by the stylus must be perpendicular to the average circumference (in the case of record sheets in disc form) or to the axis (in the case of record sheets in strip form) of the area reserved for speed recording,

• the ratio between the radius of curvature of the trace drawn by the stylus and the width of the area reserved for speed recording must be not less than 2,4 to 1, whatever the form of the record sheet,

• the markings on the time-scale must cross the recording area in a curve of the same radius as the trace drawn by the stylus. The spaces between the markings on the time-scale must represent a period not exceeding one hour.

Each variation in speed of 10 kilometres per hour must be represented on the record by a variation of at least 1,5 millimetres on the corresponding coordinate.

Recording equipment must be so constructed that the period of driving time is always recorded automatically and that it is possible, through the operation where necessary of a switch device, to record separately the other periods of time as indicated in points (ii), (iii) and (iv) of Article 34(5)(b) of this Regulation.

It must be possible, from the characteristics of the traces, their relative positions and if necessary the signs laid down in Article 34 of this Regulation, to distinguish clearly between the various periods of time. The various periods of time should be differentiated from one another on the record by differences in the thickness of the relevant traces, or by any other system of at least equal effectiveness from the point of view of legibility and ease of interpretation of the record.

In the case of vehicles with a crew consisting of more than one driver, the recordings provided for in point 4.1 must be made on separate record sheets, each record sheet being allocated to one driver. In this case, the forward movement of the separate record sheets must be effected either by a single mechanism or by separate synchronised mechanisms.