No you are right gerben, I should have thought of that from the start. There is also a discussion on Service Roads that you may want to move over here as well.

I created yet another topic to talk about the 3 highest road types (Freeway, Major Highway, and Minor Highway).

bgodette wrote: So you're of the opinion that:

Interstates are always Freeway.
US Highways are sometimes Freeway if built to interstate standard, otherwise Major
State Highways are sometimes Freeway if built to interstate standard, otherwise Minor
Other roads (unnumbered) are sometimes Freeway if built to interstate standard, otherwise Primary or below depending on functional considerations.

But you would like routing to consider Primary to be the same as Minor as far as base transit cost and route pruning.

We will see what mapcat says, but I would agree with the addition that there are cases where I'd make a State Highway Major. Specifically the case where a road is near interstate quality but is not fully limited access. One example is SR-168 (aka Pellissippi Parkway) north of I-40 in TN. Below I-40 that road is I-140, but above there are a few side street connections to ruin the limited access.

And the NJ specific conversation that started this would make numbered county routes Primary unless they are of a certain class of routes which could be Minor Highways.

mapcat wrote: Let's say you have two urban roads with similar volume, similar physical structure, similar number of curb cuts, etc. One has a state hwy number, one doesn't. Do you make the one without a number a minor highway, or do you make the one with a number a primary street?

Personally I'd make the one with a number a minor highway and the one without a primary street. I'm basing this on pure speculation that the routing server doesn't care anything about the road type in this case. Someday, I'd really like to have a long discussion about this with the routing server. Eventually I think it would come over to my side.

I agree and would handle the roads the same way.

I don't associate "highway" with physical structure, at least not in the IF physical structure=highway THEN category=(major, minor) highway sense. For example, the road we're currently calling "US Hwy 23" is sometimes a freeway, sometimes a major highway, and sometimes a minor highway in Ohio. When it goes through some small towns as a 2-lane street, it's really no more or less important than the 2-lane streets it intersects at stoplights. But they're not marked with state highway signs, so they get to be primary streets on the map, and it passes through as a minor highway.

I guess I am just fighting the distinctions in my own head. I have no problem UP-grading a road based on physical structure. If there is a county route built to interstate quality, then sure, label it as freeway type.

But I fight with the idea of DOWN-grading a road. Like when US-23 goes through a downtown, it is still a US highway and is a "major" component of the transportation network, so I'd leave it as Major unless there was a "better" bypass which could be Major instead.

US-11W here in TN is almost interstate quality but has grade intersections in my county. Heading north it goes down to 1 lane in each direction for two counties, then meets US-25E which is again close to interstate quality. That lower quality section I still have marked as Major Hwy because it is still the same road and there are no other parallel routes in that general area.

If we go with a pure physical determination, then we'd have roads changing type every few miles. If we go pure route-type determination, then we don't address bypasses.

So I think we need a hybrid where we try to balance both. Such as only changing types at intersections with roads of the same of higher type. For example US-23 shouldn't change from Major to Minor at a regular street or even a primary street. But changing at another Major or a Freeway makes sense.

I realize that I'm coming into the discussion a bit late, but here's what I've been doing in recent months (with considerable success) in rural areas of upstate NY with regard to Primary Streets. Most "county routes" came in with the basemap as Minor Highway, the same level as "state routes" -- but for the most part, they're rather unequal in real life . Thus, I've been downgrading such CR's to Primary Street, while leaving SR's at Minor Highway (and US routes mainly as Major Highway, unless they clearly should be only Minor Highway). I've also been upgrading the CR's that came in as "Street" so that they are "Primary Street".

In areas where I've done this extensively thus far (for example, Steuben County), this has been a tremendous aid in improving the routing across rural areas where there are decent CR's but no SR's. (Zoom in a level on that link and scroll around a bit, and you'll be able to see how the Primary Street network of CR's helps clarify the best ways to get around the county.) Of course, I haven't tweaked all of the CR's yet (even in this county), but there's enough there to make a remarkable improvement already. So that's one thing that PS's are definitely good for!