95 and much of 101 could be bumped to 70. In fact, 95 could be 70 MPH from Peabody MA up to where it becomes 70 in Maine.
I wouldn't make the section from Portsmouth to Kittery 70 MPH... there's a good deal of traffic, left exits, a pretty descent curve where I-95 NB leaves the turnpike, etc.
Something about 70 in urban areas in southern New England and the seacoast just seems wrong to me... I bet the average speed on I-95 north of Peabody is touching 80 as it is. I-295 from Falmouth to Brunswick ME was briefly raised to 70, then they realized it was too much and dropped it back to 65.
I meant to exclude that stretch and neglected to bring it up. Yeah that can stay at its current 55.
Unrelated, but it's also worth noting that MaineDOT (and possibly MTA as well, since part of it runs on their road past I-95 MM 0.37) scaled back the 65 MPH (105 km/h) speed limit to 55 MPH (89 km/h) from the NH/ME border to the Exit 2 on-ramp SB, and Exit 1 off-ramp NB. Only found that out en route to a game v. UNH on 22 Feb 2023 that this change was in effect.
Also just recently in the past two weeks, the foundations for breakdown lane travel (mast arms, lane use signs, sign supports, some VMS?) have also started appearing on I-95 in both states as well.