[lexicalscope]

I've heard various things about how this software is written, but in short generally there should be failsafes. I don't know where you live - but I know where I live at least a buddy that worked on writing the control software told me they have a hardware module that basically shuts down the computer controlling the light if two "conflicting" green instructions are to be sent - and sets the light into the flashing red all stop condition.

I have heard, never asked my buddy to check honestly because I never thought much of it, that prolog and various other logic languages are used to do some of the traffic light control work. As I said - I'm not sure if that's true, but if so, it would certainly make sense, and should make these kind of cases near impossible to get into.

[dllthomas]

'they have a hardware module that basically shuts down the computer controlling the light if two "conflicting" green instructions are to be sent - and sets the light into the flashing red all stop condition.'

I have heard the same thing.