Green for Danger was a 1944 detective novel by Christianna Brand, praised for its clever plot, interesting characters, and military hospital setting. The 1946 film version, starring Alistair Sim and Trevor Howard and directed by Sidney Gilliat, is regarded by film historians as one of the greatest screen adapations of a Golden Age mystery novel. 1944 was a leap year starting on Saturday (link will take you to calendar). ... 1946 was a common year starting on Tuesday. ... Alistair Sim (October 9, 1900–August 19, 1976) was a Scottish actor. ... Trevor Howard Trevor Howard (September 29, 1913 - January 7, 1988) was a British actor. ... Sidney Gilliat (February 15, 1908 – May 31, 1994) was a British film director, producer and writer. ... A whodunit or whodunnit (for Who done it? and sometimes referred to as a Golden Age Mystery novel) is a complex, plot-driven variety of the detective story in which the puzzle is paramount. ...
Where a human is the interface between technology and the control of the event such as the driving of a vehicle the perception is all important.
We all are familiar with road traffic lights yet when asked to rank the most dangerous event between the aspects of green, red and no lights because the traffic signals have broken down, the latter is the obvious choice.
However, whilst red is clearly a danger signal and usually obeyed without question, the green signal is taken as a clear indication that the driver has the right of passage.