I was born here (longer ago than I care to say) and although traffic here has always had its more congested times, it has gotten progressively worse in the past 10-15 years.
You didn't say what day of the week you would be driving down, but I can tell you that if its a weekday getting to the DC Beltway area, in particular the southbound lanes of I-95 at the area where the Beltway crosses I-95 in Virginia, between 3 and 4 PM, will see you stuck in traffic. Rush hour here begins at about 3. The worst of the traffic leaving the city is usually at about 5 or 6 PM, but even at 3 or 4 it can be quite heavy.
Leaving from where you are at 3 AM will get you here for the morning rush hour which usually lasts through around 9:30, so traffic heading into the city from points north (Baltimore) will be heavy.
Assuming it will take about 4 or 5 hours to get from where you are to the DC area, for weekday travel I recommend trying to time your arrival at the DC Beltway area to anywhere from 10 AM to about 1 or 2 PM. You will still be in some traffic, but it should be lighter and moving. If there is a fender bender during that time it will be faster getting around it. But a fender bender, or worse, a major accident, will cause tie-ups for hours in rush hour traffic.
Hope this helps.