FYI, plural of cul-de-sac is culs-de-sac. It means bottom-of-the-bag in French, so the plural form would be bottoms-of-the-bag. Like the plural of sibling-in-law is not sibling-in-laws. Worthless fact of the day!
Does it mean something different in the US? And what would be the French equivalent then?
Here’s a fairly representative picture of the geometry: https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcS8zguy...