Section 2: Determining Location
Determination of Need
Traffic engineers usually indicate signing needs on a schematic
or drawing of the location.
Field Review
After determining what signs are needed and approximately
where they should be located based on the (TMUTCD),
traffic engineers conduct a field review to refine sign locations.
Most of the field work required for plan preparation is to:
- determine estimated roadside sign post lengths for large guide signs
- determine overhead sign support spans, tower heights and drill shaft foundations, and
- determine any site restrictions and document existing or proposed conditions that could affect sign visibility.
Physical Features of Sign Placement
Many physical features may enter into the consideration of
sign placement. These include:
- right-of-way width
- driveways
- bar ditches and culverts
- trees and shrubs
- other signs and traffic control devices
- parking areas
- building overhangs
- overall sight distance due to curves and hills.
Choosing the correct sign location requires good engineering
judgment. Where possible, sign posts should not be placed in ditches
or drainage channels.
Back to Back Mounting
The shape of STOP or YIELD signs should not be obscured by
mounting a larger sign behind the STOP or YIELD sign. Where possible,
signs of different shapes should not be mounted back-to-back on
the same post.
Mounting Height
TxDOT roadside signs are mounted a minimum of 7 feet (maximum of 7.5 feet) above the edge of the travel lane, or above the grade at the base of the support, when the sign is installed on the backslope. The
and the (SCFB) provide more detail on mounting height.
Lateral Clearance
Minimum lateral clearances for both large and small roadside signs are shown in the
and the
.
Rural Intersections
Information and typical examples of appropriate signing and spacing for rural intersections can be found in the
.