The I-95/JTB exit is a remnant of when Belfort curved west at the former St Lukes (now St Vincents)and ended at Philips. Essentially a rural style exit.
JTB when conceived in the 1960's as an expressway from downtown and the beach was originally supposed to follow a ROW northwest after Southside and connect with the Commodore Point Expressway (more known as the Hart Bridge Expressway) right where it curves and ends at Beach Boulevard.
However, when the plan was announced and JTA worked to acquire the ROW, many people in the Parental Home/Hogan/Brackridge neighborhoods which predated consolidation complained that it was going to destroy their neighborhoods completely (which is correct, they would have been obliterated)
In response, Commordore Point Expressway was turned east at Beach and brought down to street level. This was easy to do because Parental Home used to end at Hogan and this was once a switching yard for the FEC Mayport Line and a logging railroad that went defunct after WWI.
JTB was then turned west at Southside towards a terminus with I-95 on top of the old Belfort Road route. However for reasons I haven't found any information on, the FHA approved design ends/begins at the Pottsburg Creek Bridge. JTB between the creek and I-95 is not considered FHA compliant. The JTB bridge over Belfort clearly shows that it was planned and built to support a future FHA compliant interchange with I-95. But I haven't seen any reasons why it was cut short the way it was.
Until I can find the T-U articles from the late 70's and early 80's that outlines any of the behind the scenes going on, I can only speculate.
