An alert Officer of the Watch makes use of any visual indications of a change of speed.
Umzekelo, bekumele iinqanawa ezinesantya ezipheleka ezinye isondelela umkhosi ngasemva kwinothi eziyi20 kwaye iyalelwe okokuba ithathe iintambo zesikhululo ezintathu kumva wenye inqanawa eqhubekeka kwiinothi eziyi12.