Both routes US 19 in Pinnelas County, FL and NJ 17 in Bergen County, NJ both have the same issues. They were both roads that had segments with at grade signalized intersections, and both had interchanges to replace them all. The only difference between the two routes in the two completely different states is how they interchanged the intersections as well as laid the roads out in general.
US 19 has put flyovers over all the cross streets and installed Texas U turns with full length service roads its whole freeway length. US 19, in fact looks like, US 75 north of Dallas and uses the Texas feeder road system for its freeway.
NJ 17 on the other hand, especially north of Paramus, built either overpasses or underpasses with ramps that jut away from the highway, and the businesses and side streets still exist on the highway itself. Built to typical NJ Freeway standards like NJ 4, and NJ 3 always were and are basically the freeway, but with driveways and side roads in between interchanges.
Of course two states DOTs and even one states regional districts can also attack a same problem two different ways which is what makes this great nation of ours great. Anyway, I wrote this post cause I find it interesting that if NJDOT was in Florida US 19 would be a Jersey Expressway and not a Texas Freeway, and if FDOT was in NJ all of Route 17 north of US 46 would be a Texas style highway.
Then again, someone once pointed out about how if NJ were FL, US Route 9 from Toms River to Lakewood would already be a six lane arterial with traffic lights every quarter mile or less, but if NJDOT were able to construct that much needed widening there, it would be only four lanes with a jersey wall center and jug handles every half mile.
A lot of it has to do with what was already there to widen a road into a Texas-style freeway and which state could foreso growth years in advance with where buildings and driveways and easements would be allowed.
Florida and Texas had massive growth after 1950 so the car culture in full swing. NJ had its heyday of innovation in the 1930s . So the obvious difference is older infrastructure in NJ. However a lot of suburban NJ was undeveloped until the same post WW2 era.(ie Ocean County) So it's not just FL new
NJ has comparatively few 6 lane arterials.. route 37 in Toms River is one if the few examples of extensive six laning in suburban NJ. In Ocean County for example FL would have much of routes 9,70, 549,528,72 as 6 lanes