Types of Supports
Through the years, the Texas Department of Transportation (TxDOT) has used many types of roadside sign supports. Since the early 1960s, the emphasis has been on the yielding or breakaway sign supports. The TMUTCD requires sign supports to be crashworthy (breakaway, yielding or shielded) if the sign is within the clear zone. All TxDOT standard supports are crashworthy. TxDOT uses several kinds of breakaway supports. The
(SMD‑Series) detail all of the designs and the appropriate size sign to be mounted on each.
An approved list of crashworthy sign supports can be found on the
. These systems are to be installed as per manufacturer directions.
The following table lists the common types of roadside sign supports. Details and procedures for these supports may be found in the Traffic Engineering Standard Sheets (SMD‑Series).
Anchor System | Sign Post | Sign Area Range |
|---|---|---|
Wedge Anchor or Universal Anchor | Thin Wall Tube | ≤ 14 sq. ft |
Triangular Slip Base | 10BWG SCH80 | > 14 sq. ft., ≤ 24 sq. ft. > 24 sq. ft., ≤ 36 sq. ft. |
Slip Base with Fuse Plate | Steel I-Beams | Large Guide Signs |
Double post installations can hold up double the square feet. The area of the regulatory or warning sign supplementary plaques is included in determining the total sign area.
Signs mounted back-to-back on a single support need only use the square footage of one sign when determining the type of sign post as the wind load is the critical factor for the post capacity.