Do sluglines work?

I have been slugging for a long time. I work 9:00 to 5:30. My office moved to 14th and L St., NW, in late 1998. I recently moved from old Springfield about 3 miles west out to West Springfield. Between the two moves, I now find that my commute time has lengthened considerably. I usually arrive at Rolling Valley parking lot around 8:20-8:30, only to find no rides to anywhere north of 14th and G streets, NW. In the evening, it takes me about 15 minutes to walk from L street down to Constitution, and at least once a week I seem to find no rides home. I realize I am rather late on the schedule, but I am beginning to think of not slugging due to this unpredictability (or rather, the predictability of not getting a ride). I should note that previously I had been going to Bob's, where rides to upper 14th street are more plentiful late. I am gettingquite frustrated. Any thoughts? I have talked to many people about getting the HOV restricted by one half hour (until 9:30 in the morning, 6:30 in the evening), but I don't think we can change that now. Some (a lot?) of this is just venting (Wednesday's commute home was hellacious), so thanks for listening.