Non-intersecting US Highways

[Alps]

You can do US 1-US 2-US 3-US 4-US 5-US 6-US 7, albeit in 5 states (ME, NH, VT, MA, CT).

That requires making a U-turn (only direct connection between US5 and US6 is 5N→6W).

We've done to death all the freeway interchange gaps, but how often do two US highways cross without an interchange?

[corco]

6 and 34 in sunny Lincoln, Nebraska.

[hbelkins]

There's really no direct connection between US 20 and US 52/61/151 in Dubuque, Iowa. You have to use various surface streets to make the connection.

[WNYroadgeek]

US 20 crosses US 219 in Orchard Park, but there's no direct connection. You have to use either NY 179 or US 20A to make the connection.

[jdb1234]

The best example I can think of is US 31/280 @ US 11 in Birmingham.  Only one movement (US 31 North to US 11) is direct, the rest involve surface streets.

[froggie]

We've done to death all the freeway interchange gaps, but how often do two US highways cross without an interchange?

US 45 and US 11/80 outside Meridian, MS.  No connection, period...US 45 is a freeway and US 11/80 is too close to I-20/59 for an interchange here.

[dfilpus]

I 140/US 17 and US 117 in Wilmington NC, where a daughter route crosses its parent without an interchange.

[Mr. Matté]

Going by official state routings, US 206 crosses over US 1 in Trenton, NJ, but there are several signed routes to connect the two (and also Business 1 too).