A new St John hospital traffic sign "north bound" found under Decor / Misc. Decor, costs 0. This is the matching pair for the St John hospital traffic sign, just in opposite direction. This one was placed on the gap between 2 lots . You need Ambitions and to place the package in both the mods/packages (Sims3 ) directory and in the "The Sims 3 Create a World Tool/ Packages" directory for the item to show in your game. There is an earlier post explaining how to install items in CAW.
Importing packages into CAW
Alternatively you can place a small lot on the side of the road and place the sign on it.
St John hospital traffic sign north bound (MediaFire)
St John hospital traffic sign for CAW
St. John hospital