A control lever arm, knob, handle, or other convenient and effective means shall be provided to set the taximeter mechanism for the desired operating condition and to clear the taximeter.
The several positions of the control lever shall be mechanically defined and displacement from any one of these positions shall be sufficiently obstructed that the accidental or inadvertent changing of the operating condition of the taximeter is improbable. Possible movement of this control to an operating position immediately following its movement to be cleared position shall be automatically delayed enough to permit the taximeter mechanism to come to a complete rest in the cleared condition.
If the control for the operating condition is a lever arm and flag, the flag shall be at its highest position when the taximeter is cleared, and in this position, the whole of the flag shall be above the level of the taximeter housing.
The knob, handle or other means provided to actuate the extras mechanism shall be inoperable whenever the taximeter is cleared.
The construction of a taximeter shall be such that there will be no interference between the time and the mileage portions of the mechanism at any speed of operation corresponding to a vehicle speed faster than the speed at which the basic rate of mileage revenue equals the basic waiting-time rate. Specifically, the registration of a taximeter in the "hired" condition shall agree with its performance in the "Time not recording" condition within one percent (1%).
Adequate provision shall be made for affixing lead-and-wire seals to a taximeter and to other parts required for service operation of a complete installation on a vehicle, so that no adjustments, alterations, or replacements affecting in any way the accuracy or indications of the device or the assembly can be made without mutilating the seal or seals. The sealing means shall be such that it is not necessary to disassemble or remove any part of the device or of the vehicle to apply or inspect the seals.