Section 2: Determining Location
Anchor: #i999791Determination of Need
Traffic engineers usually indicate signing needs on a schematic or drawing of the location.
Anchor: #i999815Field Review
After determining what signs are needed and approximately where they should be located based on the Texas Manual on Uniform Traffic Control Devices (TMUTCD), traffic engineers conduct a field review to refine sign locations.
Most of the field work required for plan preparation is to:
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- determine estimated roadside sign post lengths for large guide signs Anchor: #GYQKMWMJ
- determine overhead sign support spans, tower heights and drill shaft foundations, and Anchor: #IRBLFWEC
- 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:
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- right-of-way width Anchor: #SCKEXGOH
- driveways Anchor: #EPFWPXHN
- bar ditches and culverts Anchor: #NVJGUPNR
- trees and shrubs Anchor: #BKMXJEDT
- other signs and traffic control devices Anchor: #YABUODFP
- parking areas Anchor: #TEQBVLNS
- building overhangs Anchor: #KCJOLFRC
- 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.
Anchor: #i999854Back 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.
Anchor: #i1013888Mounting 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 TMUTCD and the Sign Crew Field Book (SCFB) provide more detail on mounting height.
Anchor: #i1013970Lateral Clearance
Minimum lateral clearances for both large and small roadside signs are shown in the Traffic Engineering Standard Sheets and the SCFB.
Anchor: #i1014030Rural Intersections
Information and typical examples of appropriate signing and spacing for rural intersections can be found in the SCFB.