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Rules For Using A Portable Stop Sign

The use of a portable stop sign is governed by rules set forth in the Manual on Uniform Traffic Control Devices (MUTCD).  The specific text for these regulations can be found here.  Below is a summation of the guidelines for using portable stop signs.


Appropriate Uses for Portable Signage

Modern traffic control makes extensive use of powered signalized devices such as flashing red lights and timed traffic signals.  These offer significant advantages over static signs, especially in terms of visibility, but in most cases they depend on an electrical grid, and if power goes out, so do the signals.  When this occurs, local authorities may need to use portable signs until electrical service is restored.  This is the most common scenario in which a portable stop sign is useful.  Some others include the following:


  • When new road construction has been completed but powered signalized devices are not yet in place.  In such cases, portable stop signs may be used for a limited time.  When possible, they should be used in conjunction with battery- or generator-powered flashing red lights.


  • When ongoing construction requires temporary changes in local traffic patterns.  If vehicles are required to stop completely at certain points during the building of an intersection, portable signage may be used.


  • When a traffic accident or other incident has temporarily disabled a permanently placed sign or signaling device.


MUTCD Rules for Using A Portable Stop Sign

The MUTCD has strict rules that regulate the size and use of portable stop signs.  A sign that faces multiple lane approaches should be a minimum of 36”x36” in size, while a sign that faces single lane approaches should be a minimum of 30”x30.” When a non-powered stop sign is used in emergency situations, it should be replaced or supplemented with a flashing red signal light as soon as possible, and in cases where side roads intersect with multi-lane roads that have speed limits of 45 mph or higher, the stop sign should be a minimum of 36”x36.”


Use of a Portable Stop Sign in School Crossing Zones

Various state codes allow the use of portable signs in school zones.  Iowa’s traffic code, for example, specifies when this type of signage may be used.  In such cases, specific rules regarding size and construction must be followed.  The sign must be a minimum of 30”x30” in size, and be permanently affixed to a mobile base.  Sign bases should have wheels on the bottom to allow easy transportation.  The state of Iowa requires the wheels to be eight inches high, although this requirement may vary from state to state.  Sign bases should also be constructed of steel, with welds holding the various components in place, and brace rods should be used at the base to stabilize the sign.  The length from the bottom of the base to the center of the sign must be between four and six feet in height.


Sign usage must also follow rules regarding its placement, including both time and location.  Signs should be supplemented with on-site crossing guards when possible, and must be removed from the site when not in use.  They should be placed in the center of the street from which traffic is approaching, not on the sides as with permanent signage, and the signage should only be used in areas that have been pre-established as school zones according to state and local laws.  Local traffic officials should regularly review the uses of portable stop signs.  If a more effective measure is feasible, such as a permanent signal device, that method should be used instead.


While a portable stop sign is subject to strict rules regarding its usage, it can serve a valuable role in unusual situations or as supplements to other traffic control measures.