Just back from a DC to Orlando trip via I-95 and I-4. There seemed to be more construction on the return trip than on the way down. Maybe it's just because DC has warped me, but I did not find the construction to be causing actual traffic. Only two times I hit traffic were on the way back through Jacksonville (series of accidents) and from Richmond to Fredericksburg (early Friday rush hour). Do advise that you use the Richmond bypass as the interstate signs suggest.
Don't know where you're coming from, but if you'll be passing through the DC area, do be advised that there can be significant traffic on the I-495/I-95 portion of the trip. Suggest you avoid 7-9AM and 4-7 PM.