As per the title, here's a screeny showing rail line choose signals and straight road choose signs working fine. However, road vehicles ignore choose signs on diagonal roads.
(http://i.imgur.com/GC86EiM.png)
This was in [r7300], however I think it also appear in an older install I had somewhere, it was about [r6900] I think.
I ran into this problem early this year on multiplayer servers as well. Was the last release version (112.3). It seems like road choose signs work differently as they can be placed on intersections and things.
please try r7303