Use of horn
5. The circumstances referred to in regulation 4(b) are that the invalid carriage is either—
(a)stationary on a road and is not in danger from another moving vehicle on or near the road; or
(b)in motion on a road which is a restricted road for the purposes of Article 37(1) of the Road Traffic Regulation (Northern Ireland) Order 1997(1) between 2330 hours and 0700 hours in the following morning.
(1)
S.I. 1997/276 (N.I. 2)