Fail Safe
Because the aspects are in reverse with more green lights meaning slower the aspects are not fail safe, so lamp proving is needed to prevent lamp failure giving a faster aspect.
Single and Double Green signals work the other way with Norwegian railway signalling and it would be unsafe for drivers to cross the border, unless ATP were fitted.
Read more about this topic: Swedish Railway Signalling
Famous quotes containing the words fail and/or safe:
“A man who speaks out honestly and fearlessly that which he knows, and that which he believes, will always enlist the good will and the respect, however much he may fail in winning the assent, of his fellow men.”
—Thomas Henry Huxley (1825–95)
“Separation anxiety is normal part of development, but individual reactions are partly explained by experience, that is, by how frequently children have been left in the care of others.... A mother who is never apart from her young child may be saying to him or her subliminally: “You are only safe when I’m with you.””
—Cathy Rindner Tempelsman (20th century)