It depends on the day. At a minimum I ride Constitution in the afternoons between 14th Street and Virginia Avenue… It is really only 4 or 5 blocks, but they are the long DC blocks. Some days I pick up Constitution further east and ride it for about half the length of the Mall.
People turning left at 15th street NW always run the red arrow. That stopped annoying me about 5 years ago. When there’s a lot of difference between our speeds, people behave like spoiled children. If we’re all going the same speed, we all get along fine.
That’s the difference between Constitution and Virginia Ave.