My daughter lives in Washington now and is an attorney there. On our last visit, we encountered women in sun dresses walking through Dupont and Georgetown at 10:30 at night. This would have been previously impossible in my experience. The story mentioned here is more indicative of 1972 DC and Hunter Thompson’s book about the Nixon campaign.
As you stated, in 1995, the hotels had signs telling you not to be out alone after dark. They were on the dressers and refrigerators in hotel rooms. In 1987, I stayed at the Washington Hilton, a huge hotel, and there was one side of it that went through a scary looking, desolate neighborhood. Apparently that neighborhood has come back to life and traveled to the front door. They need to clean that up, fast.
“Apparently that neighborhood has come back to life”
After DC got rid of Marion Barry as Mayor (and the FedGov stepped in to supervise the City), there has been a big turnaround. DC is no longer the “Murder Capital”. The downtown areas are dramatically safer. You can still run into dangerously violent individuals or groups, especially in the bad neighborhoods (some of which are still really inadvisable to walk around at night, like Anacostia), or late nights on Friday or Saturday.
Downtown areas like DuPont Circle and the tourist areas are really not that bad anymore - like an average city of that size.