What are these shaded areas? I looked in the Jeppesen legend, but couldn't find the answer. Thanks
It means that no Procedure Turn is required/expected if arriving within the sector defined by the 297 and 020 radials (inclusive) of DBL. The grey bars are a way of denoting the boundaries of the No PT sector (the entire pie section between the radials) without obstructing too much of the other details. That's why the bars are bordered on the north side of the two airways.
The Jepps wording seems to generate quite a lot of confusion because of the practice of including the words "Via Airway". I found a message thread here that might help a bit. Just remember that if confronted with something like this on a check ride and are confused, express your confusion to ATC and ask for clarification rather than blunder into a wrong move.