Route numbers that don't make sense

[RobbieL2415]

• I-495 was probably numbered with the assumption that it would cross the Sound to meet I-95 in either RI or CT (we're still waiting!); also, its westward extension across Manhattan and into NJ never happened either.

That's correct.  NJ 495 is numbered as such because it was supposed to be part of it.  (In fact, the New York side of the Lincoln Tunnel is signed incorrectly as I-495.)

If they ever build the LoMEx they should extend I-78 over it.

[paulthemapguy]

OH also the US20 and US30 designations should be swapped west of Boise, ID.

[Henry]

• I-495 was probably numbered with the assumption that it would cross the Sound to meet I-95 in either RI or CT (we're still waiting!); also, its westward extension across Manhattan and into NJ never happened either.

That's correct.  NJ 495 is numbered as such because it was supposed to be part of it.  (In fact, the New York side of the Lincoln Tunnel is signed incorrectly as I-495.)

If they ever build the LoMEx they should extend I-78 over it.

In fact, that was the plan, before it and other planned expressways (Bushwick, Nassau, etc.) were cancelled, and I-78 was truncated back to the east end of the Holland Tunnel.

[sparker]

• I-495 was probably numbered with the assumption that it would cross the Sound to meet I-95 in either RI or CT (we're still waiting!); also, its westward extension across Manhattan and into NJ never happened either.

That's correct.  NJ 495 is numbered as such because it was supposed to be part of it.  (In fact, the New York side of the Lincoln Tunnel is signed incorrectly as I-495.)

If they ever build the LoMEx they should extend I-78 over it.

In fact, that was the plan, before it and other planned expressways (Bushwick, Nassau, etc.) were cancelled, and I-78 was truncated back to the east end of the Holland Tunnel.

The original NJ/NY I-495 was to extend from I-95 east through the Lincoln Tunnel, across Manhattan and under the East River, then take the LIE out as far as then-proposed I-78 (I-295 today), where it would terminate.  The extension out onto Long Island occurred at a later time.