Tex. Parks and Wildlife Code § 28.004

(a) The department shall classify trails in the system according to the classifications established in this section. A trail may have more than one classification or may be composed of several trails with different classifications. A trail may not include the main travelway portions of highways, roads, or streets that are provided primarily for motor vehicle traffic or motor vehicle travel routes that exist or may be established on such travelways.

(b) A recreational trail is a trail that:

(1) is in or near an urban area; and

(2) is primarily used for recreational or health benefits.

(c) A scenic trail is a trail that:

(1) is in a rural or urban area;

(2) is in an area containing natural and scenic qualities of at least regional significance; and

(3) is primarily used for enjoyment of its scenic qualities and vistas, such as travel through or to a natural environment.

(d) A historic trail is a trail that:

(1) is in a rural or urban area;

(2) provides access to or between historic sites, structures, or monuments of regional or statewide significance; and

(3) is used primarily for its historic connotations, such as the significance of a historic structure or the presentation of a historic episode.

(e) An expedition trail is a trail that:

(1) is in a rural area;

(2) provides extended travel through scenic and natural areas of regional or statewide significance; and

(3) may require some travel preparation.