Draft NC highway reclassification 2022

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Stub for draft highway reclassification of North Carolina

NCDOT Functional Classifications

The North Carolina Department of Transportation classifies all roads as 1 of the following 7 categories (based on the US Department of Transportation Federal Highway Administration Functional Class):

  • Interstate
  • Other Freeway
  • Other Principal Arterial
  • Minor Arterial
  • Major Collector
  • Minor Collector
  • Local

Publicly available information is provided by NCDOT on their ArcGIS page. An interactive map of North Carolina's road system functional class can be found under the Gallery for North Carolina Department of Transportation Web Maps.

OpenStreetMap Type Matching With NCDOT

The highway classification system used in OpenStreetMap is based on the United Kingdom's classification system. To that end there is some confusion that is created from this. In an effort to simplify this process and allow for a general unification of the road classifications across North Carolina, the following guidelines are suggested:

Major Roads

Motorway

tag:highway=motorway

The Motorway classification should only be used for roads classified by NCDOT as Interstate. These roads are typically denoted as I-### (i.e., I-95).

Trunk Road

tag:highway=trunk

The Trunk classification should only be used for sections of US highways (i.e., US-70) that are classified as either Other Freeway or Other Principal Arterial.

Primary Road

tag:highway=primary

The Primary classification should only be used for road segments that are classified as Other Principal Arterial and do not meet the criteria of being a #Trunk Road road.

Secondary Road

tag:highway=secondary

The Secondary classification should only be used for road segments that are classified as Minor Arterial.

Tertiary Road

tag:highway=tertiary

The Tertiary classification should only be used for road segments that are classified as a Collector. NCDOT and the USDOT have collectors broken out into two types: Major Collector and Minor Collector. In reality, though, these roads are feeder roads for the higher functional class roads. Classifying both Collector types as Tertiary simplifies this.

Minor Roads

The Minor Roads are subtly different from each other with the exception of Track/Land-Access Road. For the sake of completeness some guidance on Minor Roads is provided below.

Minor/Unclassified Road

tag:highway=unclassified

The Minor/Unclassified Road classification should only be used for road segments that are classified as Local AND do not have residential buildings running along the majority of the segment.

Residential Road

tag:highway=residential

The Residential Road classification should only be used for road segments that are classified as Local AND is a residential area (i.e., a neighborhood).

Living Street

Tag:highway=living_street

At the time of writing, there are little to no known areas in North Carolina that meet the criteria of being classified as a Living Street. North Carolina has shared roads with designated biking lanes, but no areas other than parking lots where pedestrians can just walk out into the road.

If a Living Street classification must be used, consider using them for parking lot roads in locations such as (strip) malls and other outdoor/open shopping centers.

Follow the general OSM guidance for the appropriate usage for Living Street.

Service Road

The Service Road classification should be used for road segments that are unnamed and serve as a primary means of accessing a business. Such roads may or may not have a NCDOT functional class assignment. This guidance is similar to the general OSM guidance.

Track/Land-Access Road

tag:highway=track

Track/Land-Access Road should be used in accordance with the general OSM guidance.