Roadway Departure Safety: A Manual for Local Rural Road Owners

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Appendix B: 2009 MUTCD Standards for Traffic Control Devices

All Signs

Figure 3. MUTCD Roadside Placement (MUTCD Figure 2A-2)

For a typical rural road with no shoulder, the sign should be placed on the right-hand side of the roadway, 12 feet laterally from the edge of the traveled way. In terms of vertical height, the bottom of the sign should be installed at least 5 feet above the ground elevation at the edge of pavement. Enhancing Sign Conspicuity Cost Effectively (MUTCD, Figure 2A-2).

Figure 4. MUTCD Examples of Enhanced Conspicuity for Signs (MUTCD, Section 2A.15)

• In a situation where it is desired to enhance a sign's conspicuity, the following are among the methods that may be used:
  • Increasing the size of the sign.
  • Doubling-up by adding a second identical sign on the left-hand side of the roadway.
  • Adding a strip of retroreflective material to the sign support

Speed Limit Signs

Speed Limit (R2-1; MUTCD, Section 2B.13)

Minimum Sign Size: 24" x 30"

When to use

• The Speed Limit sign shall display the limit established by law, ordinance, regulation, or as adopted by the authorized agency based on the engineering study.
• The speed limits displayed shall be in multiples of 5 mph.
• Speed Limit signs shall be located at the points of change from one speed limit to another.
• Additional Speed Limit signs shall be installed beyond major intersections and at other locations where it is necessary to remind road users of the speed limit that is applicable.
• Speed Limit signs indicating the statutory speed limits shall be installed at entrances to the State.

Reduced Speed Limit Ahead (W3-5, W3-5a; MUTCD, Section 2C.38)

Minimum Sign Size: 36" x 36"

When to use

A Reduced Speed Limit Ahead (W3-5 or W3-5a) sign should be used to inform road users of a reduced speed zone where the speed limit is being reduced by more than 10 mph, or where engineering judgment indicates the need for advance notice to comply with the posted speed limit ahead.

Figure 5. MUTCD Example of Warning Signs for a Turn

Table 2C-5. Horizontal Alignment Sign Selection

Type of Horizontal Alignment Sign	Difference Between Speed Limit and Advisory Speed
	5 mph	10 mph	15 mph	20 mph	25 mph or more
Turn (W1-1), Curve (W1-2), Reverse Turn (W1-3), Reverse Curve (W1-4), Winding Road (W1-5), and Combination Horizontal Alignment/Intersection (W1-10) (see Section 2C.07 to determine which sign to use)	Recommended	Required	Required	Required	Required
Advisory Speed Plaque (W13-1P)	Recommended	Required	Required	Required	Required
Chevrons (W1-8) and/or One Direction Large Arrow (W1-6)	Optional	Recommended	Required	Required	Required
Exit Speed (W13-2) and Ramp Speed (W13-3) on exit ramp	Optional	Optional	Recommended	Required	Required

Horizontal Alignment Signs

All square/diamond warning signs have a minimum sign size of 30" x 30".

When to use

In advance of horizontal curves on freeways, on expressways, and on roadways with more than 1,000 AADT that are functionally classified as arterials or collectors, horizontal alignment warning signs shall be used in accordance with Table 2C-5 based on the speed differential between the roadway's posted or statutory speed limit or 85th-percentile speed, whichever is higher, or the prevailing speed on the approach to the curve, and the horizontal curve's advisory speed.

Horizontal Alignment Warning signs may also be used on other roadways or on arterial and collector roadways with less than 1,000 AADT based on engineering judgment.

Curve signs (W2-1) vs. Turn signs (W1-1) (MUTCD, Section 2C.07)

When to use

A Turn sign shall be used instead of a Curve sign in advance of curves that have advisory speeds of 30 mph or less.

Reverse Curve (W1-4) and Reverse Turn (W1-3) (MUTCD, Section 2C.07)

When to use

Where there are two changes in roadway alignment in opposite directions that are separated by a tangent distance of less than 600 feet, the Reverse Turn sign should be used instead of multiple Turn signs and the Reverse Curve sign should be used instead of multiple Curve signs.

Combination Horizontal Alignment / Intersection Warning Signs (W1-10 Series; MUTCD, Section 2C.11)

When to use

The Turn sign or the Curve sign may be combined with the Cross Road sign or the Side Road sign to create a combination Horizontal Alignment/Intersection warning sign that depicts the condition where an intersection occurs within or immediately adjacent to a turn or curve.

Elements of the combination Horizontal Alignment/Intersection warning sign related to horizontal alignment should comply with the provisions of Section 2C.07, and elements related to intersection configuration should comply with the provisions of Section 2C.46.

The symbol design should approximate the configuration of the intersecting roadway(s). No more than one Cross Road or two Side Road symbols should be displayed on any one combination Horizontal Alignment/Intersection warning sign.

Advisory Speed Plaque (W13-1P; MUTCD, Section 2C.08)

Minimum Plaque Size: 18" x 18"

Roadside Placement: The sign height changes when a speed plaque is added.

Figure 6. MUTCD Roadside Placement with Plaque

When to use

The use of the Advisory Speed plaque for horizontal curves shall be in accordance with the information shown in Table 2C-5. The Advisory Speed plaque shall also be used where an engineering study indicates a need to advise road users of the advisory speed for other roadway conditions.

If used, the Advisory Speed plaque shall carry the message XX MPH. The speed displayed shall be a multiple of 5 mph.

Except in emergencies or when the condition is temporary, an Advisory Speed plaque shall not be installed until the advisory speed has been determined by an engineering study.

The Advisory Speed plaque shall only be used to supplement a warning sign and shall not be installed as a separate sign installation.

The advisory speed shall be determined by an engineering study that follows established engineering practices. Among the established engineering practices that are appropriate for the determination of the recommended advisory speed for a horizontal curve are the following:

• An accelerometer that provides a direct determination of side friction factors
• A design speed equation
• A traditional ball-bank indicator using the following criteria:
  • 16 degrees of ball-bank for speeds of 20 mph or less
  • 14 degrees of ball-bank for speeds of 25 to 30 mph
  • 12 degrees of ball-bank for speeds of 35 mph and higher

Combination Horizontal Alignment/Advisory Speed Signs (W1-1a, W1-2a) (MUTCD, Section 2C.10)

When to use

The Turn sign or the Curve sign may be combined with the Advisory Speed plaque to create a combination Turn/Advisory Speed sign or combination Curve/Advisory Speed sign.

The combination Horizontal Alignment/Advisory Speed sign may be used to supplement the advance Horizontal Alignment warning sign and Advisory Speed plaque based upon an engineering study.

If used, the combination Horizontal Alignment/Advisory Speed sign shall not be used alone and shall not be used as a substitute for a Horizontal Alignment warning sign and Advisory Speed plaque at the advance warning location. The combination Horizontal Alignment/Advisory Speed sign shall only be used as a supplement to the advance Horizontal Alignment warning sign.

If used, the combination Horizontal Alignment/Advisory Speed sign shall be installed at the beginning of the turn or curve.

The advisory speed displayed on the combination Horizontal Alignment/Advisory Speed sign should be based on the advisory speed for the horizontal curve and match that speed.

Chevron Alignment Signs (W1-8; MUTCD, Section 2C.09)

Minimum Sign Size: 18" x 24"

Sign Design: The Chevron Alignment sign shall be a vertical rectangle. No border shall be used on the Chevron Alignment sign.

When to use

The use of the Chevron Alignment sign to provide additional emphasis and guidance for a change in horizontal alignment shall be in accordance with the information shown in Table 2C-5.

Sign Placement

If used, Chevron Alignment signs shall be installed on the outside of a turn or curve, in line with and approximately at a right angle to approaching traffic. Chevron Alignment signs shall be installed at a minimum height of 4 feet, measured vertically from the bottom of the sign to the elevation of the near edge of the traveled way.

Spacing Around Turns/Curves

The approximate spacing of Chevron Alignment signs on the turn or curve measured from the point of curvature (PC) should be as shown in Table 2C-6. Chevron Alignment signs should be visible for a sufficient distance to provide the road user with adequate time to react to the change in alignment.

One-Direction Large Arrow Sign (W1-6; MUTCD, Section 2C.12)

Minimum Sign Size: 48" x 24"

Sign Design: The One-Direction Large Arrow sign shall be a horizontal rectangle with an arrow pointing to the left or right.

When to use

A One-Direction Large Arrow sign may be used either as a supplement or alternative to Chevron Alignment signs in order to delineate a change in horizontal alignment (see Figure 2C-2). The use of the One-Direction Large Arrow sign shall be in accordance with the information shown in Table 2C-5.

A One-Direction Large Arrow sign may be used to supplement a Turn or Reverse Turn sign to emphasize the abrupt curvature.

Sign Placement

If used, the One-Direction Large Arrow sign shall be installed on the outside of a turn or curve in line with and at approximately a right angle to approaching traffic. The One-Direction Large Arrow sign should be visible for a sufficient distance to provide the road user with adequate time to react to the change in alignment.

Object Markers (MUTCD, Sections 2C.63 through 2C.65)

Minimum Sign Sizes

Type 1: 18" x 18"

Type 2: 6" x 12"

Type 3: 12" x 36"

Sign Design: Object markers shall not have a border and shall consist of an arrangement of one or more of the following types shown in Figure 2C-13.

Figure 7. MUTCD Object Markers

When to use

Type 1 object markers are used to mark obstructions within the roadway.

Type 2 and 3 object markers are used to mark obstructions adjacent to the roadway.

Obstructions not actually within the roadway are sometimes so close to the edge of the road that they need a marker. These include underpass piers, bridge abutments, handrails, ends of traffic barriers, utility poles, and culvert headwalls. In other cases there might not be a physical object involved, but other roadside conditions exist, such as narrow shoulders, drop-offs, gores, small islands, and abrupt changes in the roadway alignment, that might make it undesirable for a road user to leave the roadway, and therefore would create a need for a marker.

Object Marker Placement – Type 1, 2, 3

When used for marking obstructions within the roadway or obstructions that are 8 feet or less from the shoulder or curb, the minimum mounting height, measured from the bottom of the object marker to the elevation of the near edge of the traveled way, should be 4 feet.

When used to mark obstructions more than 8 feet from the shoulder or curb, the distance from the bottom of the object marker to the ground should be at least 4 feet.

When object markers or markings are applied to an obstruction that by its nature requires a lower or higher mounting, the vertical mounting height may vary according to need.

If a Type 2 or Type 3 object marker is used to mark an obstruction adjacent to the roadway, the edge of the object marker that is closest to the road user shall be installed in line with the closest edge of the obstruction.

No Passing Zones

Pavement Markings (MUTCD, Section 3B.02)

On roadways with center line markings, no-passing zone markings shall be used at horizontal or vertical curves where the passing sight distance is less than the minimum shown in Table 3B-1 for the 85th-percentile speed or the posted or statutory speed limit.

Figure 3B-4 details the measurements needed to determine No Passing Zones at curves.

Where the distance between successive no-passing zones is less than 400 feet, no-passing markings should connect the zones.

Sign Enhancement for No Passing Zones

No Passing Zone pavement marking can be enhanced with the following signs as desired.

Do Not Pass (R4-1) (MUTCD, Section 2B.28)

Minimum Sign Size: 24" x 30"

When to use

The DO NOT PASS sign may be used in addition to pavement markings to emphasize the restriction on passing. The DO NOT PASS sign may be used at the beginning of, and at intervals within, a zone through which sight distance is restricted or where other conditions make overtaking and passing inappropriate.

Pass With Care (R4-2) (MUTCD, Section 2B.29)

Minimum Sign Size: 24" x 30"

When to use

The PASS WITH CARE sign should be installed at the downstream end of a no-passing zone if a DO NOT PASS sign has been installed at the upstream end of the zone.

No Passing Zone pennant (W14-3) (MUTCD, Section 2C.45)

Minimum Sign Size: 48" x 48" x 36"

When to use

If signing is needed on the left-hand side of the roadway for additional emphasis, NO PASSING ZONE signs may be used.

When used, the NO PASSING ZONE sign shall be installed on the left-hand side of the roadway at the beginning of no-passing zones identified by pavement markings.

Retroreflectivity Requirements (MUTCD, Section 2A.08)

2009 MUTCD "Section 2A.08 Maintaining Minimum Retroreflectivity"

The MUTCD provides suggestions for methods to be used:

Visual Nighttime Inspection

The retroreflectivity of an existing sign is assessed by a trained sign inspector conducting a visual inspection from a moving vehicle during nighttime conditions. Signs that are visually identified by the inspector to have retroreflectivity below the minimum levels should be replaced.

Measured Sign Retroreflectivity

Sign retroreflectivity is measured using a retroreflectometer. Signs with retroreflectivity below the minimum levels should be replaced.

Expected Sign Life

When signs are installed, the installation date is labeled or recorded so that the age of a sign is known. The age of the sign is compared to the expected sign life. The expected sign life is based on the experience of sign retroreflectivity degradation in a geographic area compared to the minimum levels. Signs older than the expected life should be replaced.

Blanket Replacement

All signs in an area/corridor, or of a given type, should be replaced at specified intervals. This eliminates the need to assess retroreflectivity or track the life of individual signs. The replacement interval is based on the expected sign life, compared to the minimum levels, for the shortest-life material used on the affected signs.

Control Signs

Replacement of signs in the field is based on the performance of a sample of control signs. The control signs might be a small sample located in a maintenance yard or a sample of signs in the field. The control signs are monitored to determine the end of retroreflective life for the associated signs. All field signs represented by the control sample should be replaced before the retroreflectivity levels of the control sample reach the minimum levels.

Other Methods

Other methods developed based on engineering studies can be used.

Additional guidance on retroreflectivity requirements for various signs is provided in Table 2A-3.

Table 2A-3. Minimum Maintained Retroreflectivity Levels¹

Sign Color	Sheeting Type (ASTM D4956-04)				Additional Criteria
	Beaded Sheeting			Prismatic Sheeting
	I	II	III	III, IV, VI, VII, VIII, IX, X
White on Green	W*; G ≥ 7	W*; G ≥ 15	W*; G ≥ 25	W ≥ 250; G ≥ 25	Overhead
	W*; G ≥ 7	W ≥ 120; G ≥ 15			Ground-mounted
Black on Yellow or Black on Orange	Y*; O*	Y ≥ 50; O ≥ 50			(2)
	Y*; O*	Y ≥ 75; O ≥ 75			(3)
White on Red	W ≥ 35; R ≥ 7				(4)
Black on White	W ≥ 50				—
1 The minimum maintained retroreflectivity levels shown in this table are in units of cd/lx/m2 measured at an observation angle of 0.2 ° and an entrance angle of -4.0 °. 2 For text and fine symbol signs measuring at least 1200 mm (48 inches) and for all sizes of bold symbol signs 3 For text and fine symbol signs measuring less than 1200 mm (48 inches) 4 Minimum Sign Contrast Ratio ≥ 3:1 (white retroreflectivity ÷ red retroreflectivity) * This sheeting type should not be used for this color for this application.

Bold Symbol Signs
W1-1, -2 – Turn and Curve W1-3, -4 – Reverse Turn and Curve W1-5 – Winding Road W1-6, -7 – Large Arrow W1-8 – Chevron W1-10 – Intersection in Curve W1-15 – 270 Degree Loop W2-1 – Cross Road W2-2, -3 – Side Road W2-4, -5 – T and Y Intersection W2-6 – Circular Intersection	W3-1 – Stop Ahead W3-2 – Yield Ahead W3-3 – Signal Ahead W4-1 – Merge W4-2 – Lane Ends W4-3 – Added Lane W4-6 – Entering Roadway Added Lane W6-1, -2 – Divided Highway Begins and Ends W6-3 – Two-Way Traffic W10-1, -2, -3, -4, -11, -12 – Highway-Railroad Advance Warning W11-2 – Pedestrian Crossing	W11-3 – Deer Crossing W11-4 – Cattle Crossing W11-5 – Farm Equipment W11-6 – Snowmobile Crossing W11-7 – Equestrian Crossing W11-8 – Fire Station W11-10 – Truck Crossing W12-1 – Double Arrow W16-5p, -6p, -7p – Pointing Arrow Plaques W20-7a – Flagger W21-1a – Worker

Fine Symbol Signs – Symbol signs not listed as Bold Symbol Signs.
Special Cases
W3-1 – Stop Ahead: Red retroreflectivity ≥ 7 W3-2 – Yield Ahead: Red retroreflectivity ≥ 7; White retroreflectivity ≥ 35 W3-3 – Signal Ahead: Red retroreflectivity ≥ 7; Green retroreflectivity ≥ 7 W3-5 – Speed Reduction: White retroreflectivity ≥ 50 For non-diamond shaped signs such W14-3 (No Passing Zone), W4-4p (Cross Traffic Does Not Stop), or W13-1, -2, -3, -5 (Speed Advisory Plaques), use largest sign dimension to determine proper minimum retroreflectivity level.

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