Hong Kong Regulations

ROAD TRAFFIC (CONSTRUCTION AND MAINTENANCE OF VEHICLES) REGULATIONS - REGULATION 18

Vacuum or pressure braking systems

(1) Subject to paragraph (2) and except in the case of a motor vehicle to
which paragraph (3) applies, every motor vehicle which is equipped with a
braking system which embodies a vacuum or pressure reservoir or reservoirs
shall be provided with a warning device so placed as to be readily visible or
audible to the driver of the vehicle when in the driving seat in order to
indicate any impending failure or deficiency in the vacuum or pressure system.

(2) In the case of a vehicle the permitted gross vehicle weight of which does
not exceed 5.5 tonnes which is propelled by an internal  combustion engine and
is equipped with a braking system embodying a vacuum reservoir or reservoirs,
the vacuum therein being derived directly from the induction system of the
engine, it shall not be necessary to provide a warning device in accordance
with paragraph (1) if, in the event of a failure or deficiency in the vacuum
system, the brakes of that braking system are sufficient to provide a
braking efficiency of 50 per cent.

(3) A motor vehicle which is equipped with a braking system which uses
compressed air only as its means of operation shall be fitted with a suitable
air pressure gauge or gauges and a suitable audible warning device to indicate
low air pressure. (L.N. 203 of 1990)

(4) Where a motor vehicle to which paragraph (3) applies was manufactured on
or before 1 January 1990 or was first registered on or before 1 July 1990, it
shall be sufficient compliance with paragraph (3) if it is fitted with a
suitable air pressure gauge or gauges. (L.N. 203 of 1990)