This page serves as a supplemental tutorial to help explain some of the rationale behind select Tennessee mapping standards in greater detail than is appropriate for the primary Tennessee wiki page.
With very few exceptions, every road that is classified as Primary Street or as one of the Highway types will be found on the TDOT Functional Classification Maps. These maps are the key to understanding not only what the proper Waze road type should be, but are also used to determine state highway numbers and naming format.
Who maintains Tennessee roads?
It may be helpful to think of Tennessee roads as belonging to four overlapping networks:
Federal: A network of interstates, US highways, and state and local roads that are part of the National Highway System maintained by the state using federal funding to some degree. State roads that are part of this network can be identified on the TDOT Functional Classification Maps by the small letters "NHS" above the highway shield. These are usually classified in Waze as either Freeway or Major Highway , but occasionally as Minor Highway .
Example: in Roane/Anderson Counties, TN-95 is part of the NHS because it serves as important access to the facilities at Oak Ridge.
State and locally maintained roads found on TDOT maps: TDOT also maintains a network of state highways in each county using state funds. Overall, this is a fairly small percentage of the total road mileage in each county, and will be mapped as Freeway , Major Highway , Minor Highway , or Primary Street .
Local roads not shown on TDOT maps: Individual counties (and many cities) maintain a network of local streets and roads composing the majority of road miles within the state. These will be Street type unless they are private or unpaved roads. Individual jurisdictions may use unique road naming/numbering schemes and some maintain their own GIS websites, so road names and sources of reliable information will vary between counties. For example, Monroe and Meigs counties assign numbers to many county roads, though they may also have local names as well. Incorporated municipalities typically have their own highway departments charged with maintenance and upkeep of these roads.
National Park Service and US Forest Service roads: The NPS maintains a network of roads within national parks and various other park units, as well as two scenic roads: the Natchez Trace Parkway and the Foothills Parkway. These roads use a functional classification system that is separate from the rest of the state, and most of them do not appear on TDOT maps. See https://wiki.waze.com/wiki/National_Park_Service for mapping guidelines. These roads receive special attention by state and area managers and, in general, should not be changed before consulting with these editors.
Example: When Great Smoky Mountains National Park was established, there were already several state roads across land that was transferred to the NPS. All state highway designations were abolished within the park boundary, and no state funds are currently used to maintain roads within the park. As part of the agreement that saw TN roads turned over to the federal government, no tolls may be collected on these highways - this is why the Smokies is one of the few national parks with no entrance fee.
Within the Cherokee National Forest is a network of forest roads, many of which are only open seasonally. Like roads administered by the National Park Service, forest roads have their own naming and mapping conventions: https://wiki.waze.com/wiki/Forest_Service_Roads
How to determine road type using a TDOT FC map
This section serves as a supplement to the Functional Classification section of the TN wiki page. Be sure to review that section for current classification standards. Each map has a legend, as shown in the image below, and roads are color coded based on their intended use.
1) This is a major collector, which would typically be a primary street. But, since it is also a state highway (247) as indicated by the triangle shield, it would be upgraded to Minor Highway , the minimum Waze classification for TN numbered state highways.
2) This is also a major collector; it is identified by the name Kendron Rd and the number 01907. These five digit numbers, which usually begin with a zero, are NOT mapped in Waze, and are NOT state route numbers! They are simply internal reference numbers that TDOT uses to track locally maintained roads that are shown on their maps. Therefore, this would be a Primary Street .
3) This is a minor collector called Greens Mill Rd. It does not have a state highway number, and is maintained by the county. Similar to #2, the number 00972 is not mapped in Waze, and this would be a Primary Street .
4) This is a principal arterial road, which makes it a Major Highway . It is both US-31 and TN-6, as indicated by the presence of both shields, and is also called Main St. It is up to the editor to determine which of these three names belongs in the primary name field in Waze, and which two should be alternate names.
5) This is a freeway, TN-396, and should be a Freeway in Waze. It is also called Saturn Pkwy.