The thing is that self.bridge.angles == 0 isn't correct. The angles of an object is a 3 dimension vector.
That's why I wrote that in pseudocode, because I'm not sure how to get the angles in one direction. I mean I know that anglesToRight(self.bridge.angles) returns the bridge's angles on Y axis, but I'm not sure if the value returned is in degrees. What I mean is, I'm not sure this

if (anglesToRight(self.bridge.angles) == 180)
{
...
}

is correct.
Or maybe you could use if (self.bridge.angles) == (0, 0, 0).

On another note, by else do nothing I meant that if the bridge is not aligned on the 2 horizontal axes, the script should not continue. So you should add a iprintln("The bridge is not correctly aligned.") to let you know of the problem and also maybe a return to end the script.

@ 9837265498
You can either set the bridges angle OR use if elseif rotateroll / pitch and doing test against something other than the angle.
You mustn't use both.

You could make a prefab with an extra script_origin which is at the final drawbridge angle and make the scripts rotate the bridge to those. Then you could rotate it in any way (even 45 degrees) and it'd still work