I've been driving over 30 years and the 9th Street ramp that enters from the left side to 395 north may be the only place I'm afraid to drive in the U.S. There is no merge area, and you have about 3 seconds to decide to floor it with the 70 MPH traffic or come to a complete stop. I noticed that on the latest Google Maps Street View there is an accident and ambulance in that exact spot!
Yes, that is an
awful entrance ramp. On the left side, no acceleration lane at all, and lots of lane changing traffic ahead as I-395 northbound exits off itself on the right and into the Third Street Tunnel.
There's another one similar to that on where traffic from eastbound Benning Road, N.E. enters the northbound side of D.C. 295. It is not a drop ramp like the one from 9th Street, S.W. onto I-395 but otherwise, the geometrics are similar and there are plenty of crashes there (maybe not as many as on I-395 at the 9th Street ramp).
I use that ramp frequently and I agree with you, although I almost always use it at night so in theory it's easier to see if the lane is clear ("in theory" because a disproportionate number of residents of Southeast DC have taken to driving at night without headlights).
Last year WTOP took a poll about the worst merge in the area. I submitted that one and the reporter contacted me for an audio clip about it, which he then played on the air.
People driving around with no headlights seems to be in vogue for some reason. Or driving around with high beam lights on, even in places where it is unsafe and inappropriate.
And on most D.C. limited-access roads, there's also the matter of the "crotch rocket" motorcycles, often ridden by people with an apparent death wish, especially at night when it is warm, and on weekends and holidays.