USA Banner
  U.S. flag
              An official website of the United States government Here's how you knowOfficial US Government Icon
              **Official websites use .gov**A **.gov** website belongs to an official government organization in the United States.
            Secure Site Icon
              **Secure .gov websites use HTTPS**
                  A **lock** ( A locked padlock ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites. 
 U.S. Department of Transportation Icon United States Department of Transportation
 Search DOT
            Search
                    About FHWAFHWA Organization
                Headquarters Offices
                Field Offices
                Strategic Plan
                Business Opportunities
                Staff Directories
                Careers
                Highway History
                Contact UsProgramsAcquisition Management
                Civil Rights
                Federal Lands Highway
                Infrastructure
                Innovative Program Delivery
                Operations
                Planning, Environment, and Realty
                Policy
                Research, Development, and Technology
                Safety
                Browse by TopicsResourcesCore Highway Topics
                Federal Aid Essentials
                Automation
                Complete Streets
                Laws and Regulations
                Policy & Guidance Center
                Section 508
                Publications and Statistics
                Professional Development
                National Highway Institute
                Resource Center
                Accessibility Resource Library
                FHWA Research LibraryNewsroomPress Releases
                Speeches & Testimony
                Photos
                Videos
                Media ContactsMenu FHWA Highway Safety Programs Home
                        A Guide for Street and Highway Maintenance Personnel


            
            In This Section
        Local and Rural Road Safety Program
                Training, Tools, Guidance and Countermeasures for Locals Practitioners
                Crash Facts
                
                III. Repair and Replacement of Small Sign Supports
**Location and Height of Signs**

The location of signs is usually established by the guidance set forth in the current edition of the "Manual on Uniform Traffic Control Devices,"State standards and/or directives, and legal procedures and/or requirements.

A sign may require replacement, an additional sign may be added or a whole sign assembly (sign(s) and support) may require replacement. Do not rely on original position and height of the sign as appropriate criteria. It is important to check the location of the support and the mounting height of the sign above the roadway to ensure the sign is legible and crashworthy. Additionally, it is essential to locate small sign supports (crashworthy sign supports) so they function properly, and remember, check new sign locations to ensure there are no utility problems or sight obstructions. Before changing the location of a support or the height of a sign, check with your supervisor.

The figures below represent the recommended height and location as provided in the MUTCD.

"Roadside sign, Business or residence district: No less than 7 feet high and placed 2 feet from the roadside" ""Warning Sign with advisory speed plate, Rural district: Not less than 4 feet between the speed plate and the ground level, 12 feet from the roadside to the edge of the sign"Roadside assembly, Rural district: Not less than 5 feet from the lowest plate to the ground level, 12 feet from the roadside to the leftmost sign." "Warning sign on island in the line of traffic: 7 feet from the ground to the sign and 4 feet from the ground to the retroreflective plate"

* A height of 7' or more from the bottom of the sign to the ground is recommended in all areas where there are bus stops, pedestrians or bicycle traffic.

**Positioning Signs**

To obtain maximum reflection from traffic signs, yet eliminate specular glare, signs should be correctly aligned. Specular glare is the mirror type reflection characteristic of any glossy surface. Under severe circumstances, such as direct sunlight, specular glare can make the sign legend unreadable. Often this becomes apparent from driver complaints.

On straight sections of highway, sign should be positioned slightly away from the driver. The recommended angle, as shown below, is 93 degrees.
	"On straight sections of highway, sign should be positioned slightly away from the driver. The recommended angle, as shown, is 93 degrees"
	On curved sections of highway, the sign should be positioned at an angle of 93 degrees away from the driver at the point where the sign is to be read.
	"On curved sections of highway, the sign should be positioned at an angle of 93 degrees away from the driver at the point where the sign is to be read"
	On existing sign supports, signs can be shimmed or reattached to reduce reflective glare.To obtain a 93-degree angle for roadside signs, the device described below can be fabricated and used.

"drawing of a device to obtain a 93 degree angle for roadside signs."

**TO USE THIS DEVICE:**

Position on the ground so that a line from Nail A to Nail B is parallel to the driver's line of sight (either straight along the roadway or where the driver should first see the sign). A string or straight edge can then be placed from nails A to C to establish the appropriate sign position.

"An illustration to the usage of the device described above"

**Sign Turners**

"Graphic of a Pipe handle about four feet long and Metal U-shape the size of the post."

Pipe handle about four feet long.Shown here is a locally fabricated tool for aligning the sign and post before final tamping. A metal U-shape the size of the wood post (4"X 4" or 4"X 6") has a pipe handle welded to it. After attaching the sign to the post, filling the hole, and lightly tamping the material, one person checks the sign to make certain it is facing the roadway at the proper angle to be seen at night while the other person rotates the post with the tool.

"Drawing of a sign turning device (see description below)"

1 Pc. - 1 1/2" Black Pipe - 50" long
	1 Pc. - 5/8" x 3" x 10" long
	1 Pc. - 3/4" x 3/4" x 5/8" long
	1 Pc. - 1/4" x 3/4" x 20" long
	1 Pc. - 3/8" x 3/8" x 3" long
	1 - Clevis slip hook (remove eye)

Crashworthy Sign Supports

**Wood Post**

"Drawing of a wood post with parameters described below"
			* For rural areas, the minimum height from bottom of sign may be 5'.
			**Small supports**. Cross section is 16 sq. inches. Posts should be buried in firm ground. Minimum recommended depth is three feet. You may need to bury deeper to reduce vandalism. Do not encase post in concrete. One or two posts may be used.

			**Large Supports** should be drilled. A 6" X 8" wood post can be used if the cross section is weakened by drilling two 3-inch holes as shown in the lower drawing (drill perpendicular to roadway). A 4" X 4" is the largest undrilled wood post recommended to act as a breakaway support.
			**Maximum Post Sizes**

			Max. Sign Panel Post Size

			18" X 24" 4" X 4" nom.

			30" X 30" 4" X 6" nom.(2" holes)

			36" X 48" 6" X 6" nom.(2" holes)

			**Sign Panels**. Sign panels should be bolted to the post with oversized washers. This will prevent the panel from separating from the post on impact and then penetrating a windshield. Set the bottom of the sign panel a minimum of 7 feet above the pavement or ground. This will limit the chance of the sign and post rotating and hitting the car's windshield.**U-Channel Steel Post**

The U-channel, hot rolled steel post is the second most common small sign support. It is considered breakaway since it will bend, break or pull out of the ground when it is hit.

"Drawing of a wood post with parameters described below"
			* One post at each end of sign; not a single post made of two rails bolted together
			**Post Support.** The post should be driven into the ground and not encased in concrete. Drive posts into the ground no more than 3.5 feet to make it easier to pull out damaged posts.

			**Breakaway Devices.** Splices can be purchased commercially to install at ground level (see lower drawing). They allow the post to break off on impact. These devices improve safety when the post is hit, will make repair easier, and will make it possible to use a U-channel post when it has to be placed in a concrete area. An alternate installation is to set a stub post in the concrete with a 4-inch length available to bolt to the sign post as a base connection.

			**Maximum Post Size**

			Max. Size Panel Post Size

			18" X 24" 2 lb/ft

			30" X 30" 3 lb/ft

			36" X 48" 2 @ 2 lb/ft*

			**Sign Panels**. Sign panels should be securely bolted to the post with oversized washers. This will prevent the panel from separating from the post on impact and then penetrating a windshield. Set the bottom of the sign panel a minimum of 7 feet above the pavement or ground. This limits the chance of the sign hitting a car's windshield.**Square Steel Tube**

Another sign post is the square steel tube (perforated) design. It is used in many localities.

"Drawing of a wood post with parameters described below"
			**Post Support**. Posts can be driven into the ground. Do not place concrete around the post. A broken or damaged post is easier to remove if it is not driven or set into the ground more than three feet.

			**Breakaway Devices**. Sleeve assemblies like the one shown in the lower drawing will increase the safety of a sign when it is hit and make it easier to repair. After the sign has been hit, the broken stub of the post can be removed from the base sleeve and a new sign post put back in place.

			**Maximum Post Size**

			Max. Sign Panel Post Size

			30 " X 30" 2.25" X 2.25"

			X 0.105"

			**Sign Panels**. Attach the sign panels tightly to the post and use oversized washers to keep the sign from breaking loose from the post when a vehicle hits it. Sign panels should be mounted a minimum of 7 feet above the pavement or ground.There are many other products available commercially for sign supports. Use depends on local requirements and costs. This publication only shows four of the most common types of small sign supports.

**Slip Bases**

When installing, replacing or repairing sign support systems always follow the manufacturer's instructions to ensure proper performance.

"Photograph: slip base supports are under several inches of back fill, consequently failed to activate when hit, note the bending of the left leg"

In this case, the slip base supports are under several inches of back fill, consequently failed to activate when hit, note the bending of the left leg.

Typical torque requirements for slip base breakaway systems.

Post Size
			Pounds per Foot
			Slip Base Bolt
			Diameter (in)
			Clamping Force
			(pounds)
			Bolt Torque
			(inch-pounds)
			Max Torque
			(ft-pounds)1 - 8
			1/2
			920 - 1380
			95 - 142
			129 - 20
			5/8
			1740 - 2660
			226 - 345
			2921 - 30
			3/4
			2400 - 3600
			369 - 554
			4630 +
			1
			2400 - 3600
			460 - 735
			60Unsafe Practices

Some practices or efforts to improve maintenance can reduce the positive safety aspects of crashworthy sign and sign support designs. The following examples will give you an idea of the kind of things to watch out for. Look carefully around your own areas of responsibility to ensure that past efforts have not compromised the crashworthiness of the design or situation.

"Photograph of a back side of a sign. Note the description of this photo below."
			This sign has multiple posts supporting it when two are probably enough. Also, two horizontal braces cross the bottom. These increase the strength of the support greatly, but a small car hitting this is likely to stop suddenly, causing a severe accident. Larger posts with breakaway mechanisms at the ground are better.The environment can also be a factor on the safety characteristics of sign supports. The two most common conditions that can affect the crashworthiness of a sign support are erosion of soil at the base and the growth of trees around the support.

"Use of too many supports, either on one sign or for a group of signs can produce a hazard. This supporting system is too rigid and may contribute to overturning, loss of control or abrupt stopping."
			Use of too many supports, either on one sign or for a group of signs can produce a hazard. This supporting system is too rigid and may contribute to overturning, loss of control or abrupt stopping."This support system is now a hazard as it constitutes a rigid concrete block more than four inches above the surrounding ground. This can snag the under-carriage of a vehicle causing it to stop abruptly or go out of control."
			While the system used is a breakaway base the pedestal it is mounted on was either not back filled around or the soil has eroded around it. This support system is now a hazard as it constitutes a rigid concrete block more than four inches above the surrounding ground. This can snag the under-carriage of a vehicle causing it to stop abruptly or go out of control.
      
  Book traversal links for III. Repair and Replacement of Small Sign Supports
      ‹ II. Repair and Replacement of Sign Panels
                    Up
                    IV. Cleaning and Checking Signs and Sign Supports ›
                
                Book:A Guide for Street and Highway Maintenance Personnel
              I. Importance of Maintaining the Sign Face
                II. Repair and Replacement of Sign Panels
                III. Repair and Replacement of Small Sign Supports
                IV. Cleaning and Checking Signs and Sign Supports
                V. Materials and Equipment Used in Maintaining Signs
                VI. Traffic Control During Sign Maintenance
                VII. Sign Maintenance Records
                VIII. Resource Material U.S. DEPARTMENT OF TRANSPORTATION

**Federal Highway Administration**

1200 NEW JERSEY AVENUE, SE

WASHINGTON, DC 20590

202-366-4000Subscribe to email updates
                    About
  

        
              About FHWA
                Careers
                Org Chart
                Staff Directories
                Work with UsPrograms
  

        
              Acquisition Management
                Civil Rights
                Federal Lands Highway
                Infrastructure
                Innovative Program Delivery
                Operations
                Planning, Environment, and Realty
                Policy
                Research, Development, and Technology
                SafetyPolicies, Rights, Legal
  

        
              About DOT
                Accessibility
                Budget and Performance
                Civil Rights
                FOIA
                Information Quality
                No FEAR Act
                Office of Inspector General
                Privacy Policy
                USA.gov
                Web Policies and Notices
                Web StandardsNews & Events
  

        
              Newsroom
                Press Releases
                Speeches & Testimony
                Media Contacts
                Connect with Us