There doesn't necessarily need to be a law in place that says "all buildings adjacent to a road must have bollards", it will come down to a lot of factors outside of that. This is actually how precedents and laws are made.

For instance, if there are records of complaints or reports being made for similar incidents in the past, even for circumstances where they were near misses that didn't actually strike the building, and the property owners did nothing to take precautions against similar incidents in the future, that will work heavily against them.

As the property owners, they are liable for what happens on their property and should be working to make everything safe for their customers and other persons who are on the property, and ignoring obvious safety hazards, even if there isn't specific laws covering them, can leave them at fault.