A dead end and a Cul De Sac are the same thing...
cul-de-sac /ˈkʌldəˈsæk, -ˌsæk, ˈkʊl-; Fr. küdəˈsak/ Show Spelled Pronunciation [kuhl-duh-sak, -sak, kool-; Fr. kyduh-sak] Show IPA
–noun, plural culs-de-sac /ˈkʌlzdəˈsæk, -ˌsæk, ˈkʊlz-; Fr. küdəˈsak/ Show Spelled Pronunciation [kuhlz-duh-sak, -sak, koolz-; Fr. kyduh-sak] Show IPA . 1. a street, lane, etc., closed at one end; blind alley; dead-end street.
...you could probably use a symbol style...
the culd de sacs might need to occupy their own layer...