The road north from Ait Benhaddou to Teleouet is the ancient caravan route from sub-Saharan Africa to the North. It was only tarmaced through last summer and now it is possible to drive in an ordinary hire car along the route through which thousands of slaves were force marched to the markets of Marrakech and exotic goods such as ivory were trafficked. The local Pashas of the Glaoui tribe became very rich taking a toll of all the goods passing over the coll.
During the French occupation the Glaoui became very powerful collaborators maintaining the puppet Sultan in power and becoming faboulously wealthy. You can read about them in Gavin Maxwell's classic "Lords of the Atlas" or more briefly at the links below. However although the brothers controlled both the main passes over the Atlas, the Tizi n'Test and the Tizi n' Tichka I think the French must not really have trusted them and prepared ahead for their eventual fall because when they built the current roads in the 30s they bypassed the Glaoui kasbahs on both routes. Hence Teleouet became cut off and this road relegated to a piste. The new part of the road is very good with spectacular hairpins and views but the southern part of the old metalled part of the road south of Teouet has , strangely, not been repaired and is pot-holed for 10km or so.