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Chapter 2C. Warning Signs

Section 2C.01 Function of Warning Signs

Support:
Warning signs call attention to unexpected conditions on or adjacent to a highway or street and to situations that might not be readily apparent to road users. Warning signs alert road users to conditions that might call for a reduction of speed or an action in the interest of safety and efficient traffic operations.

Section 2C.02 Application of Warning Signs

Standard:
The use of warning signs shall be based on an engineering study or on engineering judgment.

Guidance:
The use of warning signs should be kept to a minimum as the unnecessary use of warning signs tends to breed disrespect for all signs. In situations where the condition or activity is seasonal or temporary, the warning sign should be removed or covered when the condition or activity does not exist.

Support:
The categories of warning signs are shown in Table 2C-1.

Table 2C-1. Categories of Warning Signs [D]
Category Group Section Signs MUTCD Codes
Roadway
Related		 Changes
in
Horizontal
Alignment 		2C.06 Turn, Curve, Reverse Turn, Reverse Curve, Winding Road, Hairpin Curve, 270-Degree Curve W1-1 through W1-5, W1-11, W1-15
2C.07 Combination Horizontal
Alignment/Advisory Speed 		W1-1a , W1-2a
2C.08 Combination Horizontal
Alignment/Intersection 		W1-10
2C.09 Large Arrow (one direction) W1-6
2C.10 Chevron Alignment W1-8
2C.11 Truck Rollover W1-13
Vertical Alignment 2C.12 Hill W7-1, W7-1a, W7-1b
2C.13 Truck Escape Ramp W7-4, W7-4a
2C.14 Hill Blocks View W7-6
Cross Section 2C.15 Road Narrows W5-1
2C.16-17 Narrow Bridge, One Lane Bridge W5-2, W5-3
2C.18-20 Divided Road, Divided Road Ends, Double Arrow W6-1, W6-2, W12-1
2C.21 Dead End, No Outlet W14-1, W14-1a, W14-2, W14-2a
2C.22 Low Clearance W12-2, W12-2p
Roadway Surface Condition 2C.23-24 Bump, Dip, Speed Hump W8-1, W8-2, W17-1
2C.25 Pavement Ends W8-3
2C.26 Shoulder W8-4, W8-9, W8-9a
2C.27 Slippery When Wet W8-5
2C.28 Bridge Ices Before Road W8-13
Traffic Related Advance Traffic Control 2C.29-30 Stop Ahead, Yield Ahead, Signal Ahead, Be Prepared To Stop, Speed Reduction W3-1, W3-2, W3-3, W3-4, W3-5, W3-5a
Traffic Flow 2C.31-35 Merge, Lane Ends, Added Lane, Two-Way Traffic, Right Lane Ends, Lane Ends Merge Left, No Passing Zone W4-1, W4-2, W4-3, W4-5, W4-6, W6-3, W9-1, W9-2, W14-3
Change in Speed 2C.36 Advisory Speed W13-2, W13-3, W13-5
Intersections 2C.37 Cross Road, Side Road, T, Y, and Circular Intersection W2-1 through W2-6
2C.38 Large Arrow (two directions) W1-7
2C.39 Oncoming Extended Green W25-1, W25-2
Vehicular Traffic 2C.40 Truck Crossing, Truck (symbol), Emergency Vehicle, Tractor, Bicycle, Golf Cart, Horse-Drawn Vehicle W8-6, W11-1, W11-5, W11-5a, W11-8, W11-10, W11-11, W11-12P, W11-14
Nonvehicular 2C.41-42 Pedestrian, Deer, Cattle, Snowmobile, Horse, Wheelchair, Playground W11-2, W11-3, W11-4, W11-6, W11-7, W11-9, W15-1
Supplemental Plaques Distanceempty cell 2C.45 XX Feet, XX Miles, Next XX Feet, Next XX MI W16-2, W16-3, W16-4, W7-3a
Speed 2C.46 Advisory Speed W13-1
Arrow 2C.47 Advance Arrow, Directional Arrow, Diagonal Arrow W16-5p, W16-6p, W16-7p
Hill-Related 2C.48 Trucks Use Low Gear, X% Grade W7-2, W7-3
Street Name Plaque 2C.49 Advance Street Name W16-8
Intersection 2C.50 Cross Traffic Does Not Stop W4-4p
Share The Road 2C.51 Share The Road W16-1
HOV 2C.52 High-Occupancy Vehicle W16-11
Photo Enforced 2C.53 Photo Enforced W16-10
Traffic Circle 2C.37 Traffic Circle W16-12p

Warning signs specified herein cover most of the conditions that are likely to be encountered. Additional warning signs for low-volume roads (as defined in Section 5A.01), temporary traffic control zones, school areas, highway-rail grade crossings, bicycle facilities, and highway-light rail transit grade crossings are discussed in Parts 5 through 10, respectively.

Option:
Word message warning signs other than those specified in this Manual may be developed and installed by State and local highway agencies.

Section 2C.03 Design of Warning Signs

Standard:
All warning signs shall be diamond-shaped (square with one diagonal vertical) with a black legend and border on a yellow background unless specifically designated otherwise. Warning signs shall be designed in accordance with the sizes, shapes, colors, and legends contained in the "Standard Highway Signs" book (see Section 1A.11) .

Option:
Warning signs regarding conditions associated with pedestrians, bicyclists, playgrounds, school buses, and schools may have a black legend and border on a yellow background or a black legend and border on a fluorescent yellow-green background.

Section 2C.04 Size of Warning Signs

Standard:
The sizes for warning signs shall be as shown in Table 2C-2.

Table 2C-2. Warning Sign Sizes [D]
Description Conventional Road Expressway Freeway Minimum Oversized
Shape Sign Series empty cell empty cell empty cell empty cell empty cell
Diamond W1, W2, W7, W8, W9, W11, W14, W15-1, W17-1 750 x 750
(30 x 30)		 900 x 900
(36 x 36) 		1200 x 1200
(48 x 48) 		600 x 600
(24 x 24) 		——
W1 Combination, W3, W4, W5, W6, W8-3, W10, W12 900 x 900
(36 x 36) 		1200 x 1200
(48 x 48) 		1200 x 1200
(48 x 48) 		750 x 750
(30 x 30)		 ——
Rectangular W1 - Arrows 1200 x 600
(48 x 24) 		—— —— 900 x 450
(36 x 18) 		1500 x750
(60 x 30)
W1 - Chevron 450 x 600
(18 x 24) 		750 x 900
(30 x 36) 		900 x1200
(36 x 48) 		300 x 450
(12 x 18) 		——
W7-4 1950 x 1200
(78 x 48) 		1950 x 1200
(78 x 48) 		1950 x 1200
(78 x 48) 		—— ——
W7-4b, 4c 1950 x 1500
(78 x 60) 		1950 x 1500
(78 x 60) 		1950 x 1500
(78 x 60) 		—— ——
W10-9, 10 600 x 450
(24 x 18)		 —— —— —— ——
W12-2p 2100 x 600
(84 x 24) 		2100 x 600
(84 x 24) 		2100 x 600
(84 x 24) 		—— ——
W13-2, 3, 5, W25 600 x 750
(24 x 30) 		900 x1200
(36 x 48) 		1200 x 1500
(48 x 60) 		600 x 750
(24 x 30) 		1200 x 1500
(48 x 60)
Pennant W14-3 900 x 1200 x 1200
(36 x 48 x 48)		 —— —— 750 x 1000 x 1000
(30 x 40 x 40)		 1200 x1600 x 1600
(48 x 64 x 64)
Circular W10-1 900 (36)
Dia. 		1200 (48)
Dia. 		—— 750 (30)
Dia. 		1200 (48)
Dia.
Notes:
  1. Larger signs may be used when appropriate
  2. Dimensions are shown in millimeters followed by inches in parentheses and are shown as width x height

Guidance:
The Conventional Road size should be used on conventional roads.

The Freeway and Expressway sizes should be used for higher-speed applications to provide larger signs for increased visibility and recognition.

Option:
The Minimum size may be used on low-speed roadways where the reduced legend size would be adequate for the warning or where physical conditions preclude the use of the other sizes.

Oversized signs and larger sizes may be used for those special applications where speed, volume, or other factors result in conditions where increased emphasis, improved recognition, or increased legibility would be desirable.

Standard:
The minimum size for supplemental warning plaques shall be as shown in Table 2C-3.

Table 2C-3. Minimum Size of Supplemental Warning Plaques [D]
Size of Warning Sign Size of Supplemental Plaque
Rectangular Square
1 Line 2 Lines Arrow
600 x 600 (24 x 24)
750 x 750 (30 x 30) 		600 x 300 (24 x 12) 600 x 450 (24 x 18) 600 x 300 (24 x 12) 450 x 450 (18 x 18)
900 x 900 (36 x 36)
1200 x 1200 (48 x 48) 		750 x 450 (30 x18) 750 x 600 (30 x 24) 750 x 450 (30 x 18) 600 x 600 (24 x 24)
Notes:
  1. Larger supplemental plaques may be used when appropriate
  2. Dimensions are shown in millimeters followed by inches in parentheses and are shown as width x height

Option:
Signs larger than those shown in Tables 2C-2 and 2C-3 may be used (see Section 2A.12).

Section 2C.05 Placement of Warning Signs

Support:
For information on placement of warning signs, see Sections 2A.16 to 2A.21.

The total time needed to perceive and complete a reaction to a sign is the sum of the times necessary for Perception, Identification (understanding), Emotion (decision making), and Volition (execution of decision), and is called the PIEV time. The PIEV time can vary from several seconds for general warning signs to 6 seconds or more for warning signs requiring high road user judgment.

Table 2C-4 lists suggested sign placement distances for two conditions. This table is provided as an aid for determining warning sign location.

Guidance:
Warning signs should be placed so that they provide adequate PIEV time. The distances contained in Table 2C-4 are for guidance purposes and should be applied with engineering judgment. Warning signs should not be placed too far in advance of the condition, such that drivers might tend to forget the warning because of other driving distractions, especially in urban areas.

Minimum spacing between warning signs with different messages should be based on the estimated PIEV time for driver comprehension of and reaction to the second sign.

The effectiveness of the placement of warning signs should be periodically evaluated under both day and night conditions.

Option:
Warning signs that advise road users about conditions that are not related to a specific location, such as Deer Crossing or SOFT SHOULDER, may be installed in an appropriate location, based on engineering judgment, since they are not covered in Table 2C-4.

Table 2C-4. Guidelines for Advance Placement of Warning Signs
(Metric Units)
Posted or 85th-Percentile Speed (km/h) Advance Placement Distance1
Condition A: Speed Reduction and Lane Changing in Heavy Traffic2 Condition B: Deceleration to the listed advisory speed (km/h) for the condition4
03 10 20 30 40 50 60 70 80 90 100 110
30 60 m N/A5 N/A5 N/A5 — — — — — — — — —
40 100 m N/A5 N/A5 N/A5 N/A5 — — — — — — — —
50 150 m N/A5 N/A5 N/A5 N/A5 N/A5 — — — — — — —
60 180 m 30 m N/A5 N/A5 N/A5 N/A5 N/A5 — — — — — —
70 220 m 50 m 40 m 30 m N/A5 N/A5 N/A5 N/A5 — — — — —
80 260 m 80 m 60 m 55 m 50 m 40 m 30 m N/A5 N/A5 — — — —
90 310 m 110 m 90 m 80 m 70 m 60 m 40 m N/A5 N/A5 N/A5 — — —
100 350 m 130 m 120 m 115 m 110 m 100 m 90 m 70 m 60 m 40 m N/A5 — —
110 380 m 170 m 160 m 150 m 140 m 130 m 120 m 110 m 90 m 70 m 50 m N/A5 —
120 420 m 200 m 190 m 185 m 180 m 170 m 160 m 140 m 130 m 110 m 90 m 60 m 40 m
130 460 m 230 m 230 m 230 m 220 m 210 m 200 m 180 m 170 m 150 m 120 m 100 m 70 m
Notes:

1 The distances are adjusted for a sign legibility distance of 50 m for Condition A. The distances for Condition B have been adjusted for a sign legibility distance of 75 m, which is appropriate for an alignment warning symbol sign.

2 Typical conditions are locations where the road user must use extra time to adjust speed and change lanes in heavy traffic because of a complex driving situation. Typical signs are Merge and Right Lane Ends. The distances are determined by providing the driver a PIEV time of 14.0 to 14.5 seconds for vehicle maneuvers (2001 AASHTO Policy, Exhibit 3-3, Decision Sight Distance, Avoidance Maneuver E) minus the legibility distance of 50 m for the appropriate sign.

3 Typical condition is the warning of a potential stop situation. Typical signs are Stop Ahead, Yield Ahead, Signal Ahead, and Intersection Warning signs. The distances are based on the 2001 AASHTO Policy, Stopping Sight Distance, Exhibit 3-1, providing a PIEV time of 2.5 seconds, a deceleration rate of 3.4 m/second2, minus the sign legibility distance of 50 m.

4 Typical conditions are locations where the road user must decrease speed to maneuver through the warned condition. Typical signs are Turn, Curve, Reverse Turn, or Reverse Curve. The distance is determined by providing a 2.5 second PIEV time, a vehicle deceleration rate of 3 m/second2, minus the sign legibility distance of 75 m.

5 No suggested distances are provided for these speeds, as the placement location is dependent on site conditions and other signing to provide an adequate advance warning for the driver.


Table 2C-4. Guidelines for Advance Placement of Warning Signs
(English Units)
Posted or 85th-Percentile Speed Advance Placement Distance1
Condition A: Speed Reduction and Lane Changing in Heavy Traffic2 Condition B: Deceleration to the listed advisory speed (mph) for the condition4
03 10 20 30 40 50 60 70
20 mph 225 ft N/A5 N/A5 — — — — — —
25 mph 325 ft N/A5 N/A5 N/A5 — — — — —
30 mph 450 ft N/A5 N/A5 N/A5 — — — — —
35 mph 550 ft N/A5 N/A5 N/A5 N/A5 — — — —
40 mph 650 ft 125 ft N/A5 N/A5 N/A5 — — — —
45 mph 750 ft 175 ft 125 ft N/A5 N/A5 N/A5 — — —
50 mph 850 ft 250 ft 200 ft 150 ft 100 ft N/A5 — — —
55 mph 950 ft 325 ft 275 ft 225 ft 175 ft 100 ft N/A5 — —
60 mph 1100 ft 400 ft 350 ft 300 ft 250 ft 175 ft N/A5 — —
65 mph 1200 ft 475 ft 425 ft 400 ft 350 ft 275 ft 175 ft N/A5 —
70 mph 1250 ft 550 ft 525 ft 500 ft 425 ft 350 ft 250 ft 150 ft —
75 mph 1350 ft 650 ft 625 ft 600 ft 525 ft 450 ft 350 ft 250 ft 100 ft
Notes:

1 The distances are adjusted for a sign legibility distance of 175 ft for Condition A. The distances for Condition B have been adjusted for a sign legibility distance of 250 ft, which is appropriate for an alignment warning symbol sign.

2 Typical conditions are locations where the road user must use extra time to adjust speed and change lanes in heavy traffic because of a complex driving situation. Typical signs are Merge and Right Lane Ends. The distances are determined by providing the driver a PIEV time of 14.0 to 14.5 seconds for vehicle maneuvers (2001 AASHTO Policy, Exhibit 3-3, Decision Sight Distance, Avoidance Maneuver E) minus the legibility distance of 175 ft for the appropriate sign.

3 Typical condition is the warning of a potential stop situation. Typical signs are Stop Ahead, Yield Ahead, Signal Ahead, and Intersection Warning signs. The distances are based on the 2001 AASHTO Policy, Stopping Sight Distance, Exhibit 3-1, providing a PIEV time of 2.5 seconds, a deceleration rate of 11.2 ft/second2, minus the sign legibility distance of 175 ft.

4 Typical conditions are locations where the road user must decrease speed to maneuver through the warned condition. Typical signs are Turn, Curve, Reverse Turn, or Reverse Curve. The distance is determined by providing a 2.5 second PIEV time, a vehicle deceleration rate of 10 ft/second2, minus the sign legibility distance of 250 ft.

5 No suggested distances are provided for these speeds, as the placement location is dependent on site conditions and other signing to provide an adequate advance warning for the driver.

Section 2C.06 Horizontal Alignment Signs (W1-1 through W1-5, W1-11, W1-15)

Option:
The horizontal alignment Turn (W1-1), Curve (W1-2), Reverse Turn (W1-3), Reverse Curve (W1-4), or Winding Road (W1-5) signs (see Figure 2C-1) may be used in advance of situations where the horizontal roadway alignment changes. A One-Direction Large Arrow (W1-6) sign (see Figure 2C-1 and Section 2C.09) may be used on the outside of the turn or curve.

If the change in horizontal alignment is 135 degrees or more, the Hairpin Curve (W1-11) sign (see Figure 2C-1) may be used.

If the change in horizontal alignment is approximately 270 degrees, such as on a cloverleaf interchange ramp, the 270-degree Loop (W1-15) sign (see Figure 2C-1) may be used.

Figure 2C-1 Horizontal Alignment Signs

Thumbnail image of Figure 2C-1

Guidance:
The application of these signs should conform to Table 2C-5.

Table 2C-5. Horizontal Alignment Sign Usage [D]
Number of Alignment
Changes		 Advisory Speed
< 50 km/h (< 30 MPH) > 50 km/h (> 30 MPH)
1
Turn (W1-1)1
Curve (W1-2)1
22
Reverse Turn3 (W1-3)
Reverse Curve3 (W1-4)
3 or more2 Winding Road3 (W1-5)
Notes:

1 Engineering judgment should be used to determine whether the Turn or Curve sign should be used.

2 Alignment changes are in opposite directions and are separated by a tangent distance of 180 m (600 ft) or less.

3 A Right Reverse Turn (W1-3R), Right Reverse Curve (W1-4R), or Right Winding Road (W1-5R) sign is used if the first change in alignment is to the right; a Left Reverse Turn (W1-3L), Left Reverse Curve (W1-4L), or Left Winding Road (W1-5L) sign is used if the first change in alignment is to the left.

When the Hairpin Curve sign or the 270-degree Loop sign is installed, either a One-Direction Large Arrow (W1-6) sign or Chevron Alignment (W1-8) signs should be installed on the outside of the turn or curve.

Option:
An Advisory Speed (W13-1) plaque (see Section 2C.46) may be used to indicate the speed for the change in horizontal alignment. The supplemental distance plaque NEXT XX km (NEXT XX MILES) (W7-3a) may be installed below the Winding Road sign where continuous roadway curves exist (see Section 2C.45). The combination Horizontal Alignment/Advisory Speed sign (see Section 2C.07), combination Horizontal Alignment/Intersection sign (see Section 2C.08), or the Curve Speed sign (see Section 2C.36) may also be used.

Standard:
When engineering judgment determines the need for a horizontal alignment sign, one of the W1-1 through W1-5, W1-10, W1-11 or W1-15 signs shall be used.

Option:
If the reduction in speed is 20 km/h (15 mph) or greater, a supplemental combination Horizontal Alignment/Advisory Speed sign or Curve Speed (W13-5) sign may be installed as near as practical to the point of curvature. If the reduction in speed is 40 km/h (25 mph) or greater, one or more additional Curve Speed signs may be installed along the curve.

Section 2C.07 Combination Horizontal Alignment/Advisory Speed Signs (W1-1a, W1-2a)

Option:
The Turn (W1-1) sign or the Curve (W1-2) sign may be combined with the Advisory Speed (W13-1) plaque (see Section 2C.46) to create a combination Turn/Advisory Speed (W1-1a) sign (see Figure 2C-1), or combination Curve/Advisory Speed (W1-2a) sign (see Figure 2C-1).

Standard:
When used, the combination Horizontal Alignment/Advisory Speed sign shall supplement other advance warning signs and shall be installed at the beginning of the turn or curve.

Section 2C.08 Combination Horizontal Alignment/Intersection Sign (W1-10)

Option:
The Turn (W1-1) sign or the Curve (W1-2) sign may be combined with the Cross Road (W2-1) sign or the Side Road (W2-2 or W2-3) sign to create a combination Horizontal Alignment/Intersection (W1-10) sign (see Figure 2C-1) that depicts the condition where an intersection occurs within a turn or curve.

Guidance:
Elements of the combination Horizontal Alignment/Intersection sign related to horizontal alignment should conform to Section 2C.06, and elements related to intersection configuration should conform to Section 2C.37. No more than one Cross Road or two Side Road symbols should be shown on any one combination Horizontal Alignment/Intersection sign.

Section 2C.09 One-Direction Large Arrow Sign (W1-6)

Option:
A One-Direction Large Arrow (W1-6) sign (see Figure 2C-1) may be used to delineate a change in horizontal alignment.

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

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 shall not be used where there is no alignment change in the direction of travel, such as at the beginnings and ends of medians or at center piers.

Guidance:
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.

Section 2C.10 Chevron Alignment Sign (W1-8)

Option:
The Chevron Alignment (W1-8) sign (see Figure 2C-1) may be used to provide additional emphasis and guidance for a change in horizontal alignment. A Chevron Alignment sign may be used as an alternate or supplement to standard delineators on curves or to the One-Direction Large Arrow (W1-6) sign.

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

If used, Chevron Alignment signs shall be installed on the outside of a turn or curve, in line with and at approximately a right angle to approaching traffic.

Option:
A Chevron Alignment sign may be used on the far side of an intersection to inform drivers of a change of horizontal alignment for through traffic.

Guidance:
Spacing of Chevron Alignment signs should be such that the road user always has at least two in view, until the change in alignment eliminates the need for the signs.

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.

Section 2C.11 Truck Rollover Warning Sign (W1-13)

Option:
A Truck Rollover Warning (W1-13) sign (see Figure 2C-1) may be used to warn drivers of vehicles with a high center of gravity, such as trucks, tankers, and recreational vehicles, of a curve or turn having geometric conditions that are prone to cause such vehicles to lose control and overturn.

Standard:
When the Truck Rollover Warning (W1-13) sign is used, it shall be accompanied by an Advisory Speed (W13-1) plaque indicating the recommended speed for vehicles with a higher center of gravity.

Option:
The Truck Rollover Warning sign may be displayed either as a static sign, a static sign supplemented by a flashing warning beacon, or as a changeable message sign activated by the detection of an approaching vehicle with a high center of gravity that is traveling in excess of the recommended speed for the condition.

Support:
The curved arrow on the Truck Rollover Warning sign shows the direction of roadway curvature. The truck tips in the opposite direction.

Section 2C.12 Hill Signs (W7-1, W7-1a, W7-1b)

Guidance:
The Hill (W7-1) sign (see Figure 2C-2) should be used in advance of a downgrade where the length, percent of grade, horizontal curvature, and/or other physical features require special precautions on the part of road users.

Figure 2C-2 Vertical Grade Signs

Thumbnail image of Figure 2C-2

The Hill sign and supplemental grade (W7-3) plaque (see Section 2C.48) used in combination, or the W7-1b sign used alone, should be installed in advance of downgrades for the following conditions:

  1. 5% grade that is more than 900 m (3,000 ft) in length;
  2. 6% grade that is more than 600 m (2,000 ft) in length;
  3. 7% grade that is more than 300 m (1,000 ft) in length;
  4. 8% grade that is more than 230 m (750 ft) in length; or
  5. 9% grade that is more than 150 m (500 ft) in length.

These signs should also be installed for steeper grades or where crash experience and field observations indicate a need.

Supplemental plaques (see Section 2C.48) and larger signs should be used for emphasis or where special hill characteristics exist. On longer grades, the use of the Hill sign with a distance (W7-3a) plaque or the combination distance/grade (W7-3b) plaque at periodic intervals of approximately 1.6 km (1 mi) spacing should be considered.

Standard:
When the percent grade is shown, the message X% plaque shall be placed below the inclined ramp/truck symbol (W7-1) or the word message HILL (W7-1a) sign.

Option:
The word message HILL (W7-1a) sign may be used as an alternate to the symbol (W7-1) sign. The percent grade message may be included within these signs.

Section 2C.13 Truck Escape Ramp Signs (W7-4 Series)

Guidance:
Where applicable, truck escape (or runaway truck) ramp advance warning signs (see Figure 2C-2) should be located approximately 1.6 km (1 mi), and 800 m (0.5 mi) in advance of the grade, and of the ramp. A sign also should be placed at the gore. A RUNAWAY VEHICLES ONLY (R4-10) sign (see Figure 2B-8) should be installed near the ramp entrance to discourage other road users from entering. No Parking (R8-3) signs should be placed near the ramp entrance.

Standard:
When truck escape ramps are installed, at least one of the W7-4 series signs shall be used.

Option:
A SAND (W7-4d), GRAVEL (W7-4e), or PAVED (W7-4f) supplemental plaque (see Figure 2C-2) may be used to describe the ramp surface. State and local highway agencies may develop appropriate word message signs for the specific situation.

Section 2C.14 HILL BLOCKS VIEW Sign (W7-6)

Option:
A HILL BLOCKS VIEW (W7-6) sign (see Figure 2C-2) may be used in advance of a crest vertical curve to advise road users to reduce speed as they approach and traverse the hill as only limited stopping sight distance is available.

Guidance:
When a HILL BLOCKS VIEW sign is used, it should be supplemented by an Advisory Speed (W13-1) plaque indicating the recommended speed for traveling over the hillcrest based on available stopping sight distance.

Section 2C.15 ROAD NARROWS Sign (W5-1)

Guidance:
A ROAD NARROWS (W5-1) sign (see Figure 2C-3) should be used in advance of a transition on two-lane roads where the pavement width is reduced abruptly to a width such that vehicles might not be able to pass without reducing speed.

Figure 2C-3 Miscellaneous Warning Signs

Thumbnail image of Figure 2C-3

Option:
Additional emphasis may be provided by the use of object markers and delineators (see Chapters 3C and 3D). The Advisory Speed (W13-1) plaque (see Section 2C.46) may be used to indicate the recommended speed.

Section 2C.16 NARROW BRIDGE Sign (W5-2)

Guidance:
A NARROW BRIDGE (W5-2) sign (see Figure 2C-3) should be used in advance of any bridge or culvert having a two-way roadway clearance width of 4.9 to 5.5 m (16 to 18 ft), or any bridge or culvert having a roadway clearance less than the width of the approach travel lanes.

Additional emphasis should be provided by the use of object markers, delineators, and/or pavement markings.

Option:
A NARROW BRIDGE sign may be used in advance of a bridge or culvert on which the approach shoulders are narrowed or eliminated.

Section 2C.17 ONE LANE BRIDGE Sign (W5-3)

Guidance:
A ONE LANE BRIDGE (W5-3) sign (see Figure 2C-3) should be used on two-way roadways in advance of any bridge or culvert:

  1. Having a clear roadway width of less than 4.9 m (16 ft); or
  2. Having a clear roadway width of less than 5.5 m (18 ft) when commercial vehicles constitute a high proportion of the traffic; or
  3. Having a clear roadway width of 5.5 m (18 ft) or less where the sight distance is limited on the approach to the structure.

Additional emphasis should be provided by the use of object markers, delineators, and/or pavement markings.

Section 2C.18 Divided Highway (Road) Sign (W6-1)

Guidance:
A Divided Highway (W6-1) symbol sign (see Figure 2C-3) should be used on the approaches to a section of highway (not an intersection or junction) where the opposing flows of traffic are separated by a median or other physical barrier.

Option:
The word message DIVIDED HIGHWAY (W6-1a) or DIVIDED ROAD (W6-1b) sign (see Figure 2C-3) may be used as an alternate to the symbol sign.

Section 2C.19 Divided Highway (Road) Ends Sign (W6-2)

Guidance:
A Divided Highway Ends (W6-2) symbol sign (see Figure 2C-3) should be used in advance of the end of a section of physically divided highway (not an intersection or junction) as a warning of two-way traffic ahead.

Option:
The Two-Way Traffic (W6-3) symbol sign (see Section 2C.34) may be used to give warning and notice of the transition to a two-lane, two-way section.

The word message DIVIDED HIGHWAY ENDS (W6-2a) or DIVIDED ROAD ENDS (W6-2b) sign (see Figure 2C-3) may be used as an alternate to the symbol sign.

Section 2C.20 Double Arrow Sign (W12-1)

Option:
The Double Arrow (W12-1) sign (see Figure 2C-3) may be used to advise road users that traffic is permitted to pass on either side of an island, obstruction, or gore in the roadway. Traffic separated by this sign may either rejoin or change directions.

Guidance:
If used on an island, the Double Arrow sign should be mounted near the approach end.

If used in front of a pier or obstruction, the Double Arrow sign should be mounted on the face of, or just in front of, the obstruction. Where stripe markings are used on the obstruction, they should be discontinued to leave a 75 mm (3 in) space around the outside of the sign.

Section 2C.21 DEAD END/NO OUTLET Signs (W14-1, W14-1a, W14-2, W14-2a)

Option:
The DEAD END (W14-1) sign (see Figure 2C-3) may be used at the entrance of a single road or street that terminates in a dead end or cul-de-sac. The NO OUTLET (W14-2) sign may be used at the entrance to