Drastic road standard changes

[PHLBOS]

US 202 at the PA 611 cloverleaf near Doylestown, PA: 4-lane divided expressway north of the interchange to a 2-lane undivided parkway south of it.

[bzakharin]

Woodhaven Road in Philly goes from a full freeway to a dead-end street without so much as a marked median after a single at-grade intersection

[pdx-wanderer]

The Summerlin Parkway progresses from freeway to arterial to total dead end in less than a mile.

[roadfro]

The Summerlin Parkway progresses from freeway to arterial to total dead end in less than a mile.

Well actually,  it turns into an arterial at the CC 215 interchange (traffic lights), and hasn't yet been constructed beyond said beltway interchange. If and when Summerlin Pkwy is built beyond the 215, it is planned to be a surface arterial.

[pdx-wanderer]

The Summerlin Parkway progresses from freeway to arterial to total dead end in less than a mile.

Well actually,  it turns into an arterial at the CC 215 interchange (traffic lights), and hasn't yet been constructed beyond said beltway interchange. If and when Summerlin Pkwy is built beyond the 215, it is planned to be a surface arterial.

Which makes perfect sense and it's clearly left with room to easily expand but until that happens though, it definitely fits for this list, I think.

[jakeroot]

The Summerlin Parkway progresses from freeway to arterial to total dead end in less than a mile.

Well actually,  it turns into an arterial at the CC 215 interchange (traffic lights), and hasn't yet been constructed beyond said beltway interchange. If and when Summerlin Pkwy is built beyond the 215, it is planned to be a surface arterial.

Which makes perfect sense and it's clearly left with room to easily expand but until that happens though, it definitely fits for this list, I think.

If you and a mate were driving along US-95 at its interchange with the Summerlin Parkway, and you told them that the overhead ramps led to a freeway that dead-ends in a desert in about six miles, you'd at least get some sort of "seriously?" response. I think it should qualify for the time being.

[wxfree]

These are examples of high-standard roads changing to not-high standard roads.  My first thought goes to an example on the other end of the scale.  Texas FM 1576 runs north to the New Mexico state line, then runs east along the state line, and then the road turns north and changes into a county road in New Mexico.  FM 1576 is a narrow two-lane highway but has very little traffic and other than three right angles is suitable for highway speeds.  The county road it turns into is very rough and requires low speed and great care.  It's rocky, so getting stuck in mud isn't a worry, but any speed higher than a crawl imposes a constant pounding.  This is a change from a normal road to a very low standard road that happens instantly.