903.4 Guide Signs—Conventional Roads (MUTCD Chapter 2D)
903.4.1 Scope of Conventional Road Guide Sign Standards and Application (MUTCD Section 2D.01)
Standard. The provisions of this EPG 903.4 shall apply to any road or street other than expressways and freeways, except as otherwise provided in the EPG.
Support. Guide signs direct road users along streets and highways; inform them of intersecting routes; direct them to cities, towns, villages, or other important destinations; identify nearby rivers and streams, parks, forests, and historical sites; and provide information that will help them along their way in the most simple and direct manner possible.
Guidance. The selection of primary or control destinations (those displayed consistently over longer distances along a route) displayed on guide signs should be meaningful to road users in navigation and orientation. The destinations selected should be identifiable on official maps.
Support. EPG 903.1 addresses placement, location, and other general criteria for signs.
903.4.2 Color, and Retroreflection, and Illumination (MUTCD Section 2D.02)
Support. Requirements for illumination, retroreflection, and color are stated under the specific headings for individual guide signs or groups of signs. General provisions are given in EPG 903.1.6, 903.1.21, and 903.1.22.
Standard. Except as otherwise provided in the EPG for individual signs or groups of signs, guide signs on streets and highways shall have a white message and border on a green background. All messages, borders, and legends shall be retroreflective and all backgrounds shall be retroreflective.
Support. Color coding is sometimes used to help road users distinguish between multiple potentially confusing destinations. Examples of valuable uses of color coding include guide signs for roadways approaching or inside an airport property with multiple terminals serving multiple airlines, and community wayfinding guide signs for various traffic generator destinations within a community or area.
Standard. Except as otherwise provided in the EPG, different color sign backgrounds shall not be used to provide color coding of destinations. The color coding shall be accomplished by the use of different colored square or rectangular sign panels on the face of the guide signs (see Figure 903.4.2).
Option. The different colored sign panels on the face of a sign may include a black or white (whichever provides the better contrast with the panel color) letter, numeral, or other appropriate designation to identify an airport terminal or other destination.
Support. EPG 903.4.48 contains specific provisions regarding Community Wayfinding guide signs.
903.4.3 Size of Signs (MUTCD Section 2D.03)
Standard. Except as provided in EPG 903.1.7, the minimum sizes of conventional road guide signs that have standardized designs shall be as shown in Table 903.4.3.
Support. EPG 903.1.7 contains information regarding the applicability of the various columns in Table 903.4.3.
Option. Signs larger than those shown in Table 903.4.3 may be used (see EPG 903.1.7) for special applications where speed, volume or other factors result in conditions where increased emphasis, improved recognition or increased legibility would be desirable, with approval from the MoDOT Highway Safety and Traffic Division.
Support. For other guide signs, the legends are so variable that a standardized design or size is not appropriate. The sign size is determined primarily by the length of the message, and the size of lettering and spacing necessary for proper legibility.
Option. Reduced letter height, reduced interline spacing, and reduced edge spacing may be used on guide signs if sign size must be limited by factors such as lane width or vertical or lateral clearance.
Guidance. Reduced spacing between the letters or words on a line of legend should not be used as a means of reducing the overall size of a guide sign, except where determined necessary by engineering judgment to meet unusual lateral-space constraints. In such cases, the legibility distance of the sign legend should be the primary consideration in determining whether to reduce the spacing between the letters or the words or between the words and the sign border, or to reduce the letter height.
When a reduction in the prescribed size is necessary, the design used should be as similar as possible to the design for the standard size.
| Placeholder | Table |
|---|---|
903.4.4 Lettering Style (MUTCD Section 2D.04)
Standard. The design of upper-case letters, lower-case letters, numerals, route shields, and spacing shall be as provided in the EPG articles and FHWA’s “Standard Highway Signs” publication (see EPG 911 (MUTCD Section 1A.05)).
The lettering for names of places, streets, and highways on conventional road guide signs shall be a combination of lower-case letters with initial upper-case letters (see EPG 903.1.8). The nominal loop height of the lower-case letters shall be ¾ the height of the initial upper-case letter. When a mixed-case legend letter height is specified referring only to the initial upper-case letter, the height of the lower-case letters that follow shall be determined by this proportion. When the height of a lower-case letter is referenced, the reference is made to the nominal loop height. The height of the initial upper-case letter shall also be determined by this proportion.
All other word legends on conventional road guide signs shall be in upper-case letters.
The unique letter forms for each of the Standard Alphabet series shall not be stretched, compressed, warped, or otherwise manipulated. Modifications to the length of a word for a given letter height and series shall be accomplished only by the methods described in EPG 903.4.3 and shall be approved by the MoDOT Highway Safety and Traffic Division.
903.4.5 Size of Lettering (MUTCD Section 2D.05)
Support. Sign legibility is a direct function of letter size and spacing. Legibility distance has to be sufficient to give road users enough time to read and comprehend the sign. Under optimum conditions, a guide sign message can be read and understood in a brief glance. The legibility distance takes into account factors such as inattention, blocking of view by other vehicles, unfavorable weather, inferior eyesight, or other causes for delayed or slow reading. Where conditions permit, repetition of guide information on successive signs gives the road user more than one opportunity to obtain the information needed.
Standard. Design layouts for conventional road guide signs shall be provided by the MoDOT Highway Safety and Traffic Division.
Except as otherwise provided in the EPG, the principal legend on post-mounted guide signs shall be in letters and numerals at least 6 inches in height for all upper-case letters, or a combination of 6 inches in height for upper-case letters and 4.5 inches in nominal loop height (see EPG 903.4.4) for lower-case letters.
Except as otherwise provided in the EPG, the principal legend on overhead guide signs shall be in letters and numerals at least 6 inches in height for all upper-case letters, or a combination of 6 inches in height for upper-case letters and 4.5 inches in nominal loop height (see EPG 903.4.4) for lower-case letters.
Guidance. Lettering sizes should be consistent on any particular class of highway.
The minimum lettering and numeral sizes provided in the EPG (see Table 903.4.5.1) should be exceeded where conditions indicate a need for greater legibility.
| Placeholder | Table |
|---|---|
| Placeholder | Table |
|---|---|
903.4.6 Amount of Legend (MUTCD Section 2D.06)
Support. The longer the legend on a guide sign, the longer it will take road users to recognize and comprehend it, regardless of letter size.
Guidance. Except where otherwise provided in the EPG, guide signs should be limited to no more than three lines of destinations, which include place names, route numbers, street names, and cardinal directions. Where two or more signs are included in the same overhead display, the amount of legend should be further minimized. Where appropriate, a distance message or action information, such as an exit number, NEXT RIGHT, or directional arrows, should be provided on guide signs in addition to the destinations.
903.4.7 Abbreviations (MUTCD Section 2D.07)
Support. The use of commonly recognized abbreviations for certain words can be useful in reducing the reading time and improve quicker comprehension of a sign message. Descriptors and directional or quadrant orientations for street names and destinations, such as Boulevard (Blvd), North (N), and Southwest (SW), are some examples of commonly recognized abbreviations. Examples of the use of some guide sign abbreviations are shown in Figure 903.4.7.
Standard. The words NORTH, SOUTH, EAST, and WEST shall not be abbreviated when used to indicate cardinal directions of numbered or named highways on guide signs.
Guidance. Abbreviations should be kept to a minimum; however, they are useful when complete destination messages produce excessively long signs. If used, abbreviations should be unmistakably recognized by road users (see EPG 911 (MUTCD Section 1D.08)). Longer commonly used words that are not part of a proper name and are readily recognizable, such as street name descriptors (such as Street, Boulevard, or Avenue), should be abbreviated as provided in Table 903.4.7.1 to expedite recognition of the sign legend by reducing the amount and complexity of the legend. Shorter street name descriptors, such as those shown in Table 903.4.7.2, should not be abbreviated.
Periods, apostrophes, question marks, ampersands, or other punctuation or characters that are not letters, numerals, or hyphens should not be used in abbreviations, unless necessary to avoid confusion.
The solidus is intended to be used for fractions only and should not be used to separate words on the same line of legend. Instead, a hyphen should be used for this purpose, such as “TRUCKS – BUSES.”
903.4.8 Arrows (MUTCD Section 2D.08)
Support. Arrows are used for lane assignment and to indicate the direction toward designated routes or destinations. Figure 903.4.8 shows the various standard arrow designs that have been approved for use on guide signs. Detailed drawings for these arrows will be provided by the MoDOT Highway Safety and Traffic Division.
Standard. Except for Overhead Arrow-per-Lane signs (see EPG 903.4.33), on overhead signs where it is desirable to indicate a lane to be followed, a down arrow shall be positioned over the approximate center of the lane and shall point vertically downward toward the approximate center of that lane. Down arrows shall be used only on overhead guide signs that restrict the use of specific lanes to traffic bound for the destination(s) and/or route(s) indicated by these arrows. Down arrows shall not be used unless an arrow can be located over and pointed to the approximate center of each lane that can be used to reach the destination displayed on the sign.
If down arrows are used, having more than one down arrow pointing to the same lane on a single overhead sign (or on multiple signs on the same overhead sign structure) shall not be permitted.
Where a roadway is leaving the through lanes, a directional arrow shall point upward at an angle that approximates the alignment of the exit roadway in the vicinity of the point of departure.
The Type E directional arrow for circular intersections shall not be used on any sign that is not associated with a circular intersection.
Guidance. The Type A directional arrow should be used on guide signs on freeways, expressways, and conventional roads to indicate the direction to a specific destination or group of destinations, except as otherwise provided in this Article and in Section 2E.18.
When a directional arrow in a vertical, upward-pointing orientation is placed to the side of a group of destinations to indicate a through movement, the Type A directional arrow should be used. When a directional arrow in a vertical, upward-pointing orientation is placed to the side of a single destination or under a destination or group of destinations, the Type B directional arrow should be used.
The Type B directional arrow should be used on guide signs on conventional roads when placed at any angle to the side of a single destination or when placed in a horizontal orientation to the side of a group of destinations.
The Type C advance turn directional arrow should be used on conventional road guide signs placed in advance of an intersection where a turn must be made to reach a posted destination or group of destinations.
The Type D directional arrow should be used primarily for sign applications other than guide signs, except as provided in the fourth Option paragraph below.
If the Type E directional arrow is used, the principles set forth in EPG 903.4.22 through 903.4.25 should be followed.
Option. The Type A-Extended directional arrow may be used on guide signs where additional emphasis regarding the direction is needed relative to the amount of legend on the sign.
The Type C directional arrow may be used to the side of the legend of an overhead guide sign to accentuate a sharp turn exit maneuver from a mainline roadway (see Section 2E.25 for additional information regarding Exit Direction signs for low advisory ramp speeds).
On conventional roads on the approach to an intersection where the Combination Lane-Use/Destination overhead guide sign (see EPG 903.4.24) is not used, the Type C advance turn directional arrow may be used beneath the legend of an overhead guide sign to indicate the fact that a turn must be made from a mandatory movement lane over which the sign is placed to reach the destination or destinations displayed on the sign.
The Type D directional arrow may be used on post-mounted guide signs on conventional roads with lower operating speeds if the height of the text on the sign is 8 inches or less. Type D arrows may be used on a Street Name (D3-1 only) sign displaying two street names to indicate the different direction of travel for each street.
The Type E directional arrow may be used on guide signs on approaches to circular intersections to represent the intended driver paths to destinations involving left-turn movements around the circulatory island.
The directional and down arrows shown in Figure 903.4.8 may be used on signs other than guide signs for the purposes of providing directional guidance and lane assignment.
Guidance. Arrows used on guide signs to indicate the directions toward designated routes or destinations should be pointed at the appropriate angle to clearly convey the direction to be taken. A horizontally-oriented directional arrow design should be used at right-angle intersections.
On a post-mounted guide sign, a directional arrow for a straight-through movement should point upward. For a turn, the arrow on a guide sign should point horizontally or at an upward angle that approximates the sharpness of the turn.
At an exit, an arrow should be placed at the side of the sign that will reinforce the movement of exiting traffic. The directional arrow design should be used.
Standard. If used, the Type C advance turn directional arrow shall display a right or left arrow, the shaft of which is bent at a 90-degree or oblique angle.
Option. Arrows may be placed below the principal sign legend or on the appropriate side of the legend that is consistent with the direction of the movement.
On a post-mounted sign at an exit where placement of the arrow to the side of the legend farthest from the roadway would create an unusually wide sign that limits the road user's view of the arrow, the directional arrow may be placed at the bottom portion of the sign, centered under the legend.
Guidance. The width across the arrowhead for the Types A, B, and C directional arrows should be between 1.5 and 1.75 times the height of the upper-case letters of the principal legend on the sign. The width across the arrowhead for the Type D directional arrow should be at least equal to the height of the upper-case letters of the principal legend on the sign. For down arrows used on overhead signs, the width across the arrowhead should be approximately 2 times the height of the upper-case letters of the principal legend on the sign.
Support. EPG 903.4.33 contains the provisions for arrows used in Overhead Arrow-per-Lane signs on approaches to conventional road intersections. Section 2E.41 contains the provisions for arrows used in Diagrammatic Advance guide signing on approaches to conventional road intersections other than circular intersections. EPG 903.4.35 contains the provisions for diagrammatic arrows used in Destination signs on the approaches to circular intersections.
The FHWA’s “Standard Highway Signs” publication (see EPG 911 (MUTCD Section 1A.05)) and Standard Plan 903.01 contains design details and standardized sizes of the various arrows based on ranges of letter heights of principal legends.
903.4.9 Numbered Highway Systems (MUTCD Section 2D.09)
Support. The purpose of numbering and signing highway systems is to identify routes and facilitate travel.
The Interstate and United States (U.S.) highway systems are numbered by the American Association of State Highway and Transportation Officials (AASHTO) upon recommendations of the State highway organizations because the respective States own these systems. State and county road systems are numbered by the appropriate authorities.
The basic policy for numbering the Interstate and U.S. highway systems is contained in the following Purpose and Policy statements published by AASHTO:
- A. “Establishment and Development of United States Numbered Highways,” and
- B. “Establishment of a Marking System of the Routes Comprising the National System of Interstate and Defense Highways.”
Guidance. The principles of these policies should be followed in establishing the highway systems described in the preceding paragraph and any other systems, with effective coordination between adjacent jurisdictions. Care should be taken to avoid the use of numbers or other designations that have been assigned to Interstate, U.S., or State routes in the same geographic area. Overlapping numbered routes should be kept to a minimum.
Standard. Route systems shall be given preference in this order: Interstate, United States, State, and county. The preference shall be given by installing the highest-priority route number on the top or the left of the sign, except as provided in the Option paragraph below.
Interstate route numbering shall be approved by the FHWA.
Option. The prioritization of route systems may be modified when a different prioritization would better accommodate the expectancy of the road user and provide more effective direction, such as for separate decision points for routes that are encountered in a particular order.
903.4.10 Route Signs and Auxiliary Plaques (MUTCD Section 2D.10)
Standard. Except as provided in the third Option paragraph of EPG 903.4.25, all numbered highway routes shall be identified by route signs and auxiliary plaques.
The signs for each system of numbered highways, which are distinctive in shape and color, shall be used only on that system and the approaches thereto.
Option. Route signs and auxiliary plaques may be proportionally enlarged where greater conspicuity or legibility is needed.
Support. Route signs are typically mounted in assemblies with auxiliary plaques.
EPG 903.4.49 contains information regarding the signing for National Scenic Byways.
EPG 903.4.50 contains information regarding the signing for Missouri Scenic Byways, historic trails, and auto tour routes.