Highway Numbering
Tennessee currently observes the following Standardized Name nomenclature for Numbered Routes:
| Road Type | Standardized Name |
|---|---|
| Freeways | I-XXX |
| US Highways | US-XXX |
| Primary State Highways | TN-XXX |
| Secondary State Highways | SR-XXX |
| County Highways | CR-XXX |
These naming conventions should also be applied to "Old" numbered routes that have become local streets after the completion of new highway alignments. For example, "Old State Rte 33" and "Old US Hwy 70" Should be renamed "Old TN-33" and "Old US-70" respectively. In some cases, it may be necessary to research whether the old route was formerly a state or US highway.
State Highway Signage
State highways are divided into primary and secondary classifications and use a different type of signage for each:
Tennessee Primary State Route signage: use format TN-155 and shieldː 
Tennessee Secondary State Route signage: use format SR-171 and shieldː 
Should that road be Primary or Secondary?
In order to determine which naming format to use, check Street View and the TDOT FC Maps (Link) to verify sign shape. Most US highways in Tennessee are also assigned a "hidden" state route number, in which case one will be unable to find state highway signs in Street View. For example, TN-1 follows US-70 and several other US highways across most of the state from Memphis to Bristol, but is only signed in certain areas. These state highway designations, where they exist, should be listed in the alternate name for the US highway segment.
Also note that state routes can change between primary and secondary designation depending on their intended use. For example, TN-25 in Gallatin has a short stretch that is classified as SR-25.
If primary or secondary status cannot be determined, it is acceptable to default to TN-xxx format.
Highway Naming
See Road names and Road types for general guidelines for naming and classifying roads.
Regarding Local and Alternate Names:
In situations where a highway passes through a town, the road in those areas is typically named something other than the numbered route. In these situations the road should be named based on the following conditions: If the local street signs provide guidance with the local name, that should be used as the primary name in the Waze map. The numbered route should be added as an alternate name. If the local signs only indicate the route number, then that should be the primary name and and the local road name should be added as an alternate name.
Example: TN-13 in Waverly, TN has a Local Name of S Church St. (as indicated by signage). The Primary Street Name of the segments is S Church St., while TN-13 is listed as an Alternate Street Name.
Regarding Overlapping Highways:
When two or more numbered highways (or interstates) run concurrently (one stretch of road has multiple route numbers), the segment should be named after the primary of the routes. The primary route will usually have one or more of the following attributes:
- The route whose mile markers are used for the concurrent segment
- The route whose exit numbers are used for the concurrent segment
- When the concurrency ends, the route whose path does not get signed as a numbered exit.
In Tennessee, most US highways are also assigned a "hidden" state route number. These routes are often unsigned when they share a concurrency with a US highway. For example, TN-1 follows US-70 and several other US highways across most of the state from Memphis to Bristol, but is only signed in certain areas. These state highway designations, where they exist, should be listed in the alternate name for the US highway segment.
Regarding Scenic Routes:
Although Tennessee's roads tend to be quite scenic in and of themselves, many highways are specially designated as scenic routes and are signed with a green and white mockingbird logo. However, the "Scenic" or "Scn" designations should not be included in road names on numbered highways, unless specifically named as such in state GIS sources. Do not treat these like bannered routes when determining road names.
Lists of Highways in Tennessee
Interstate and US Highways in Tennessee
Functional Classification
A road's type is determined by a two step method:
- Classification via TDOT Functional Classification maps
- Possible classification upgrade due to highway type
Step 1: Classification via TDOT Generated Functional Classification
The Tennessee Functional Class Map is updated by the the Tennessee Department of Transporation (TDOT). Using the TDOT maps, the Corresponding Waze Road Type is determined via the following two tables:
TDOT Functional Classification
| TDOT Functional Class | Corresponding Waze Road Type |
|---|---|
| Interstate (blue) | Freeway |
| Other Freeways and Expressways (brown) | Freeway (if Controlled-access highway) or Major Highway otherwise (see note below) |
| Principal Arterial (red) | Major Highway |
| Minor Arterial (green) | Minor Highway |
| Major Collector (purple) | Primary Street |
| Minor Collector (yellow) | Primary Street |
Note: The editor should check to see if a road is a Controlled-access highway to determine if it qualifies as a Freeway . Partially-limited-access roads, however, should NOT be set to Freeway.
If a road is not shown on the Functional Classification Maps, it is deemed as a Local Road with a Waze Road Type of Street .
Inconsistent switching between road types along a road is not wanted. Consistency is key. Do not change a road type for routing sake or to make it appear on the map at a higher speed.
Sometimes strictly following these functional classification guidelines will generate inconsistent Waze road types at boundaries between urban and rural maps. It is best to use the aerial maps and GPS data to find a logical location where a road should make the change in road type. These types of changes are usually at intersections with other roads (primary street and above) and sometimes incorporate a change in lane count (2-lane road transitions to 4-lane road). Prudent editor discretion is needed at these locations.
Step 2: Classification upgrades via highway type
Sometimes, after determining road type in step 1, a road will need to be upgraded if it is an Interstate, Federal Highway, or State Highway. The list below provides the minimum that a particular highway should be classified (e.g. a Urban Collector would be at a minimum a primary street, but it would be upgraded to a major highway if it was a US Highway or a minor highway if it were a State Highway).
- Freeway - Interstates
- Major Highway - US Highways
- Minor Highway - State Highways (Both Primary and Secondary State Routes), US Business Highways
Quick Reference Table
This chart is an alternative presentation of the two steps above which can provide a handy reference.
To use this chart, first determine the functional class of a road. Secondly, determine whether it is a signed, numbered highway in a particular highway system.
Where the column for the road's highway system and the row for the road's Tennessee functional class meet, you will find the proper road type for that particular road.
A number of examples are given below the chart.
| Highway Systems | ||||||
|---|---|---|---|---|---|---|
| Interstate | US Hwy | US Hwy BUS, SPUR, LOOP | State Hwy | Locally-maintained | ||
| examples | I-40, I-75, I-240, I-275 | US-70, US-11E, US-41A | US-412 BUS, US-11E BUS | TN-1, SR-33, TN-840 | Sam Cooper Blvd. | |
| T N F u n c t i o n a l C l a s s |
Interstate (blue) | Fw | N/A | N/A | N/A | N/A |
| Other Freeways and Expressways (brown) (Controlled-access highway) |
N/A | Fw | Fw | Fw | Fw | |
| Other Freeways and Expressways (brown) (Partially-limited-access road) |
N/A | Major | Major | Major | Major | |
| Principal Arterial (red) (Controlled-access highway) |
N/A | Fw | Fw | Fw | Fw | |
| Principal Arterial (red) (Non-controlled-access highway) |
N/A | Major | Major | Major | Major | |
| Minor Arterial (green) | N/A | Major | Minor | Minor | Minor | |
| Major Collector (purple) | N/A | Major | Minor | Minor | PS | |
| Minor Collector (yellow) | N/A | Major | Minor | Minor | PS | |
| Local/not mapped | N/A | Major | Minor | Minor | Street | |
For example,
- A State Highway that is a controlled-access highway classified as a Principal Arterial is a Freeway .
- A State Highway that is a partially-limited-access road classified as a Principal Arterial is a Major Highway .
- A US Highway classified as a Minor Arterial is a Major Highway .
- A US Highway Business Route route classified as a Minor Arterial is a Minor Highway .
- A State Highway classified as a Freeway is a Freeway .
- A State Highway classified as a Principal Arterial is a Major Highway .
- A State Highway classified as a Collector is a Minor Highway .
- A locally-maintained road classified as an Principal Arterial is a Major Highway .
- A locally-maintained road classified as a Collector is a Primary Street .
Road Locking
Tennessee currently observes the following Locking Levels for Functional Classifications:
| Segment Type | Abbr. | Lock |
|---|---|---|
| Freeway | Fw | 5 |
| Ramp | Highest lock of connected segment | |
| Major Highway | MH | 4 |
| Minor Highway | mH | 3 |
| Primary Street | PS | 2 |
| Street | N/A | Automatic (1) |