Hong Kong Regulations

ROAD TRAFFIC (CONSTRUCTION AND MAINTENANCE OF VEHICLES) REGULATIONS - REGULATION 57

Guard rails

(1) If any two wheels on the same side of a bus have a clear space of more
than 600 millimetres between their nearest points, a guard rail, running board
or other similar device, which shall extend to within 220 millimetres of the
front wheel and 150 millimetres of the rear wheel, shall be fixed to guard
such space effectively to within at least 250 millimetres of the ground when
the vehicle is carrying no passengers and is standing on level ground.

(2) Any guard rail fitted in compliance with this regulation shall be so
constructed and fitted that, when necessary, by raising the rail or otherwise,
access can easily be obtained to any part of the space underneath the vehicle.