Displayed by a Colour Light SignalA Signal that conveys its information by coloured lights., indicates to the driver that, in Three or
Four Aspect SignallingA system of colour light signalling which provides Red, Yellow, Double Yellow and Green Aspects in a manner which normally provides a First Caution at least two..., the next SignalA visual display device which conveys instructions or provides prior warning of instructions regarding the driver’s authority to proceed. will be displaying a Proceed AspectAny Signal Aspect which permits the driver to pass the Signal..
See also Two Aspect SignallingA system of colour light signalling normally employing Red/Green Two Aspect Stop Signals only (as commonly used on London Underground). Yellow/green Repeater Si....