Road Types

OK, so here's the road type plan that Blyzz & I debated IRL the other day. I'll lay out our proposed standards first and then get to the reasoning afterwards.

• Freeways: Any national road (with an N prefix) should always be classified as a freeway in Waze, even where it passes through the middle of a one-horse town and has its speed limit reduced to 60kph.
  
  Major Highways: Major arterial roads, as indicated on any maps produced by the Directorate of Surveys & Mapping, or identified as such by SANRAL or the provincial roads department responsible for their upkeep are major highways. These roads have an Rnn naming structure, where nn represents a two digit number (eg: R27), and their road sides enclose their names in a rhombus/diamond shape, and they're typically the primary roads that connect cities and towns to each other.
  
  Minor Highways: Surveys & Mapping's maps call these secondary roads. Their designations are R's followed by three digit numbers. eg: R304, R102.
  
  Primary Streets: In metropolitan areas anything with an M prefix is automatically (at least) a primary street, but there will be of plenty of other major roads that qualify as primary streets without the M prefix. In rural areas, it's probably appropriate to use primary streets for district roads that have a D prefix, but probably not for private roads (P prefixes).
  
  Promotion: Anything roads from Primary Streets upwards can have segments of their length upgraded to freeway status where appropriate, but only in those segments. You can generally identify genuine freeways by the presence of freeway starts/ends signs at the beginning and end and, most importantly, the absence of intersecting crossroads. ie: Freeway road segments have fly-offs (or ramps) and don't have stop streets or traffic lights. eg: The M3 in Cape Town is a freeway Westlake to the top of Wynberg Hill and from Newlands Ave all the way to Vredehoek, but the section in between (Edinburgh Dr & Paradise Rd) is just a primary street because it has traffic lights and other intersections with side roads connecting directly to it. See https://world.waze.com/cartouche/?zoom= ... ayers=BTFT
  
  Demotion: Roads don't get demoted below the status they inherit from their prefix or naming structure at any point in their length. So, just as the N2 remains a national road (and hence a freeway in Waze classification) where it runs through that intolerable stretch of traffic lights in the Somerset West/Strand area, so the R27 is always a major highway even in the sections where it's interrupted by lots of traffic lights.

I think the N vs Rnn vs Rnnn vs M breakdown is a pretty clear guideline that should work for us 99% of the time. The biggest question that Blyzz & I debated was what happens to highways when they pass through the centres of towns or cities. In some of the roads I've previously labelled, I demoted major highways to primary streets where they pass through towns with traffic lights or just plain old stop streets, but that's inconsistent with the treatment of national roads, many of which are also subjected to the indignity of stop signs in some areas, and I think inconsistencies are dangerous ground in naming standard! An even bigger motivation for not demoting roads, though, is that lower level roads like primary streets aren't visible when you zoom out too far on the live map or on our mobile clients, and so if you're visually scanning a route through a town, highways that get demoted would seem to disappear through the middle of the towns, and that's never confidence-inspiring.

All comments welcome as usual.