We honestly should have a graph connection here between the two routes. Would recommend using the location that I-395 use for that interchange mess.
Also, the following exit number should be adjusted in both I-395/US-1's files:
10 -> 10A (It's signed as 10A both ways,
NB &
SB)
Also would recommend adding a new point to I-395 for the Express interchange @ Eads St, as that's a complete interchange. Especially since that's the northern end of the 'reversible' system too where it splits into separate lanes for each direction so that it can be open 24/7 into/out of DC.