Authorization for classifying, making, and signing state highways is provided to TxDOT under of the Texas Transportation Code. The Texas Reference Marker (TRM) system marks the highway so that all data collected and recorded identifies the correct section of road in the Texas Department of Transportation (TxDOT) database. The Transportation Planning and Programming Division (TPP) has established a highway system hierarchy listing all classes of highways in the database. On roadways having more than one route number assigned to them, it is very important that the route markers (M1 series) be mounted according to the roadway system hierarchy shown in Figure 7-2 to help data collectors record the proper highway number.

Markers for higher ranked systems are mounted either

above or to the left

of lower ranked systems.

EXAMPLE: If a US and state highway are concurrent, the US shield is mounted above or to the left of the state highway shield.

Markers within a direction or highway class are arranged by number. Lower numbers are mounted either

above or to the left

of higher numbers.