This has been discussed at laborious length several times in the forum, as well as there being the wiki road type and naming standards. In general, I am making state hwy a minor, US hwy a major, and interstates a freeway. There are exceptions like state hwys built to interstate limited access standards, but those are a minority.

I do it the same as Alan.

AlanOfTheBerg wrote:This has been discussed at laborious length several times in the forum...

...and yet nobody's ever comfortable taking the next step to codifying it. (Maybe that's intentional.)

So yes, currently road type is de facto subjective. My general guidelines FWIW:

Freeway: a freeway is a freeway is a freeway. Some people are uncomfortable applying this to expressways with short entrance ramps or curves that require drivers to slow down to 40 mph, but almost always, if the road is divided, lacks traffic lights, and only accessible via grade-separated interchanges, it's a freeway.

Major highway: a freeway with occasional at-grade intersections, a multi-lane divided or undivided highway that is the preferred route into a city from a freeway or other major highway, and primary 2-lane roads that act as the most direct routes between small cities (pop around 25k or greater). In the US all of these will be state or US highways (and possibly even a few county highways in states that sign them).

Minor highway: any other road with a US or State highway number (plus county highways in some states).

Primary street: in cities, typically a road whose intersections with other roads of the same or greater rank are controlled by traffic lights. Most of the time in urban and suburban areas these will have at least 3 lanes, or at minimum dedicated turn lanes at light-controlled intersections. In rural areas, these are county roads that directly connect roads of higher rank to small communities, state parks, significant industrial areas, etc.

The most detailed discussion I could find on this subject is in this topic, which illustrates the ideas with some Google Street View images on page 3.

unwallflower wrote:San Diego has very few US Highways.

Does SD have any US highways anymore? The 101 was truncated to LA or Orange Co a while back, wasn't it?

Around here, in the 1920s politicians had a lot more pull (and/or the east had more politicians), so every little cow path was nominated for consideration as a US highway at some point. If they were major highways, I'd show them that way, but many of them just handle local traffic, especially those shadowed by interstates.

I adhere to the method that mapcat described almost exactly.

You know, I really do follow both Alan AND mapcat's methods.

San Diego has very few US Highways, and nearly all State Highways here are limited access (and therefore marked at interstates).

I'm with Alan and I admit to starting some of the past discussions and also admit not taking them to the point of codification. I have my first baby on the way and have had much less time to devote to Waze recently.