18. (1) A driver intending to slow down, stop, or alter course, shall either give a signal by using a direction indicator or stop lamp, as appropriate, or give the appropriate hand signal set out in Table A in the Second Schedule.

(2) A driver shall indicate the direction in which the vehicle is to be driven to a member of the Garda Síochána by giving either a signal by using a direction indicator or the appropriate hand signal set out in Table B in the Second Schedule.

(3) A driver shall give a signal in sufficient time before altering course and in such a manner as to be clearly visible and clearly understood by those for whom such signal is intended.

(4) A driver shall not give simultaneous contradictory signals.