Why? The entire argument for self driving cars is that they are safer drivers than humans. If that claim breaks down whenever the driving conditions are anything other than perfect, then self driving cars lose their only supposed benefit. If we have to substantially change everything we do on or around the road to simply help them match human efficacy then (1) what is the point of a "self driving" car that can trivially encounter breaking conditions and (2) if these changes would be beneficial safety why haven't we already done them for human drivers?

Also the picture in the article shows both cones and workers, the presence of either would generally cause a human to alter how they drive.

What we see consistently is self driving cars that randomly stop in perfectly reasonable driving conditions, and similarly we see repeated cases of them driving through clearly unsafe areas. If a single human driver repeatedly made these same mistakes they would lose their license, but for some reason we allow it from these unsafe self driving systems. If a car manufacturer ships a car that is found to operate unsafely, the manufacturer is required to recall them, and isn't allowed to return the car to market until the problem is demonstrably fixed.