a fire engine used for the purpose of extinguishing fires, of preserving life and property in case of fire or of aiding or rescuing persons in danger, or in case of an accident;
(b)
an ambulance used for the purpose of aiding or rescuing persons in danger, or in case of an accident; or
(c)
a motor vehicle owned by the Government and used by the Singapore Police Force for the purpose of executing its functions,
if compliance with these Rules would be likely to hinder the use of the fire engine, ambulance or vehicle for the purpose for which it is being used.