A SignalA visual display device which conveys instructions or provides prior warning of instructions regarding the driver’s authority to proceed. which gives the driver the first indication of a need to stop at a
SignalA visual display device which conveys instructions or provides prior warning of instructions regarding the driver’s authority to proceed. ahead. See also Caution (Aspect)An Aspect which advises the driver that the next Signal may be at Danger. It is indicated by a Single Yellow (Aspect) or a Semaphore Distant arm horizontal. and Preliminary Caution (Aspect)A Signal Aspect which informs the driver to expect the next Signal to be at Caution. It is indicated by a Double Yellow Aspect..