TDOT Route ID Naming Structure

The Route ID is 10 positions and comprised of the following concatenation: County, Route, Special Case, and County Sequence.

The County position 2 digits (01 – 95) assigned to each of the 95 counties.

The Route position is 5 characters that indicate one of the following prefix codes:

Prefix codes:

SR - State Route (i.e., SR001)

I - Interstate Route (i.e., I0040)

00 - 09 - Functionally Classified Route (i.e. 00811 or 05413)

0A - 0Z - Local Road (i.e. 0A001) (0I, 0S, 0U not available)

The Special Case is 1 digit that indicate one of the following codes:

Codes:

0 – None

1 – Spur

2 – Alternate

3 – State Connector

4 – Bypass

5 – Business Route

6 – Northbound

7 – Southbound

8 – Eastbound

9 – Westbound

The County Sequence is 2 digits. It indicates the number of times a route has left and re-entered a county. For most routes, this value will be “01.” If the route leaves the county and returns to the county, the value will be “02” and increment each time the route subsequently leaves and reenters the county. Each time the route reenters the county, a new route record will be created.