Advice on Beltway Bottlenecks

I got a letter about Beltway traffic this morning that I thought I'd share with the group, because I love the idea the writer speaks of: A map that would show where the typical tie-ups occur. What would you want to color in on such a map? In the morning, there's the outer loop from about Greenbelt around to Georgia Avenue. That's a splotch I'd color in. Also, the outer loop in the morning around Tysons.

In the afternoon, there's the inner loop in Maryland from the Legion Bridge through the I-270 split and the outer loop from the Telegraph Road area to the Wilson Bridge.

What am I forgetting?

To answer her specific question about the trip to the Eastern Shore, I'll warn her that backups can occur anywhere for a variety of reasons, but that she's likely to encounter delays on either loop of the Beltway at some point. I wouldn't advise going through the District. I don't see how that would speed the trip. And I'll warn about potential backups at the Bay Bridge on Friday afternoons, though it should be easier now that summer holidays are over.

This is the letter:

Dear Dr. Gridlock,
Do you know of a map that shows the typical morning and evening rush hour traffic back ups around the Beltway? My husband and I live in Falls Church (Fairfax Co.) and are planning a trip to the Eastern Shore of Maryland. We plan to leave on a Friday afternoon and were wondering which way around the Beltway we should go.