Section 2: Warning Sign Advance Placement
Introduction
Warning signs are placed in advance of a potential hazard.
The Texas MUTCD presents basic information in Table 2C-4 of the
manual. The information in this section expands upon the information in
the Texas MUTCD.
Advance Placement Condition Descriptions
The placement of a warning sign is based on the potential
hazard the sign warns of and the amount of advance warning needed
by a road user. There are
two
placement conditions:- Condition Arepresents a situation that involves a complex driving decision, often in heavy traffic conditions. Lane changes in heavy traffic, exiting maneuvers, and merging traffic are common examples. This condition typically applies to freeways and high volume urban arterial situations that require additional response time.
- Condition Brepresents a condition where a vehicle may have to stopor slow downas a result of the potential hazard identified by the warning sign.
Relation Between Minimum Distances and Sign Crew Field Book Distance
The minimum advance placement distances for warning signs
shown in the next subsection are intended primarily for installation
of isolated warning signs. When a warning sign is installed as part
of a series of signs, it may be appropriate to place a warning sign
further from the potential hazard than the values indicated in the
table. In particular, warning signs on the approach or departure
from an intersection are placed using the distances shown in the
figures in Chapters 5 and 6 to maintain the system perspective with
all the signs on the approach or departure.
Advance Placement Distance for Warning Signs
Warning signs are placed in advance of a potential hazard based on the roadway speed limit, the type of response needed (the condition), and the speed associated with the warning sign response. Table 2-1 presents the minimum advance placement distances for warning signs. This table is an expansion of the information in Table 2C-4 from the Texas MUTCD,
including speed limits of 80 and 85 mph, as well as advisory speeds ending in 5 (i.e. 15)
. Table 2-2 provides a description of each condition and information about which warning signs are associated with each condition.Minimum Advance Placement Distance 1 (ft) | |||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Posted Speed or 85th Percentile (mph) | Condition B: Deceleration to the listed advisory speed (mph) for the condition | ||||||||||||||||||
Condition A: Speed reduction and lane changing in heavy traffic 2 | |||||||||||||||||||
B: Stop 3 | 5 4 | 10 4 | 15 4 | 20 4 | 25 4 | 30 4 | 35 4 | 40 4 | 45 4 | 50 4 | 55 4 | 60 4 | 65 4 | 70 4 | 75 4 | 80 4 | |||
20 | 225 | 100 6 | NA 5 | NA 5 | NA 5 | — | — | — | — | — | — | — | — | — | — | — | — | — | |
25 | 325 | 100 6 | NA 5 | NA 5 | NA 5 | NA 5 | — | — | — | — | — | — | — | — | — | — | — | — | |
30 | 460 | 100 6 | NA 5 | NA 5 | NA 5 | NA 5 | NA 5 | — | — | — | — | — | — | — | — | — | — | — | |
35 | 565 | 100 6 | NA 5 | NA 5 | NA 5 | NA 5 | NA 5 | NA 5 | — | — | — | — | — | — | — | — | — | — | |
40 | 670 | 125 | 100 6 | 100 6 | 100 6 | 100 6 | NA 5 | NA 5 | NA 5 | — | — | — | — | — | — | — | — | — | |
45 | 775 | 175 | 125 | 125 | 125 | 100 6 | 100 6 | 100 6 | NA 5 | NA 5 | — | — | — | — | — | — | — | — | |
50 | 885 | 250 | 200 | 200 | 200 | 175 | 150 | 125 | 100 6 | 100 6 | NA 5 | — | — | — | — | — | — | — | |
55 | 990 | 325 | 275 | 275 | 275 | 225 | 225 | 200 | 150 | 125 | 100 6 | NA 5 | — | — | — | — | — | — | |
60 | 1,100 | 400 | 350 | 350 | 350 | 325 | 300 | 275 | 225 | 200 | 150 | 100 6 | 100 6 | — | — | — | — | — | |
65 | 1,200 | 475 | 450 | 450 | 425 | 400 | 400 | 350 | 325 | 275 | 225 | 200 | 125 | 100 6 | — | — | — | — | |
70 | 1,250 | 550 | 525 | 525 | 525 | 500 | 475 | 450 | 425 | 375 | 325 | 275 | 225 | 150 | 100 6 | — | — | — | |
75 | 1,350 | 650 | 625 | 625 | 625 | 600 | 575 | 550 | 500 | 475 | 425 | 375 | 325 | 250 | 200 | 100 6 | — | — | |
80 | 1,475 | 750 | 750 | 725 | 725 | 700 | 675 | 650 | 600 | 575 | 525 | 475 | 425 | 350 | 300 | 225 | 150 | — | |
85 | 1,575 | 850 | 850 | 850 | 825 | 800 | 775 | 750 | 725 | 675 | 625 | 575 | 525 | 475 | 400 | 325 | 250 | 150 | |
1 The distances are adjusted for a sign legibility distance of 180 feet for Condition A. The distances for Condition B have been adjusted for a sign legibility distance of 250 feet, which is appropriate for an alignment warning symbol sign. For Conditions A and B, warning signs with less than 6-inch legend or more than four words, a minimum of 100 feet should be added to the advance placement distance to provide adequate legibility of the warning 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 PRT of 14.0 to 14.5 seconds for vehicle maneuvers (2004 AASHTO Policy, Exhibit 3-3, Decision Site Distance, Avoidance Maneuver E) minus the legibility distance of 180 feet 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 2004 AASHTO Policy, Exhibit 3-1, Stopping Site Distance, providing a PRT of 2.5 seconds, a deceleration rate of 11.2 feet/second2 minus the sign legibility distance of 250 feet.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 PRT, a vehicle deceleration rate of 10 feet/second2 minus the sign legibility distance of 250 feet.5 No suggested distances are provided for these speeds, as the placement locations are dependent on site conditions and other signing. An alignment warning sign may be placed anywhere from the point of curvature up to 100 feet in advance of the curve. However, the alignment warning sign should be installed in advance of the curve and at least 100 feet from any other signs.6 The minimum advance placement distance is listed as 100 feet to provide adequate spacing between signs. | |||||||||||||||||||
Conditions Associated with Specific Warning Signs
Table 2-2 lists the signs that are associated with the
two
conditions (A and B) used in Table 2-1. Condition B is separated into warning signs that require a stop, and warning signs that require a speed reduction. Two other conditions are included that do not pertain to Table 2-1: warning signs that do not require a speed reduction, and warning signs that are placed at the road hazard.
Condition | Applicable Warning Signs | |
|---|---|---|
A: Complex Maneuver | W4-1, Merging Traffic W4-1aT, Thru Traffic Merge Right (Left) W4-2, Lane Ends | W4-5, Entering Roadway Merge W9-1, Right (Left) Lane Ends W9-2T, Lane Ends Merge Left (Right) |
B: Stop | W2-1, Cross Road W2-1aT, Highway Intersection Ahead W2-2, Side Road (perpendicular) W2-3, Side Road (oblique) W2-4, T-intersection symbol W2-5, Y-intersection symbol W2-6, Circular intersection W2-6aT, Traffic Islands Ahead W2-7, Offset Side Road W2-8, Double Side Road W3-1, Stop Ahead W3-2, Yield Ahead W3-3, Signal Ahead W3-4, Be Prepared to Stop W3-6, Draw Bridge W3-7, Ramp Meter Ahead W3-7aT, Ramp Signal Ahead W3-8, Ramp Metered When Flashing W5-3, One Lane Bridge W8-6, Truck Crossing W8-13aT, Bridge May Ice in Cold Weather W8-14, Fallen Rocks W8-18, Road May Flood W8-18aT, Water Crossing W8-18bT, When Flooded Turn Around Don’t Drown W10-1, Grade Crossing Advance Warning W10-2, Parallel Railroad Crossing (cross road) W10-3, Parallel Railroad Crossing (side road) W10-4, Parallel Railroad Crossing (T road) W10-4a & W10-4b, Train When Flashing W10-5, Low Ground Clearance W10-11, Railroad T Crossing W10-12, Railroad Skewed Crossing W11-1, Bicycle Crossing W11-2, Pedestrian Crossing W11-3, Deer Crossing | W11-4, Cow Crossing W11-5 & W11-5a, Farm Vehicle W11-6, Snowmobile Crossing W11-7, Equestrian Crossing W11-8, Fire Station W11-9, Handicapped Crossing W11-10, Truck Crossing W11-11, Golf Cart Crossing W11-12T, Watch for Emergency Vehicles W11-12aT, Emergency Vehicles Entering Intersection When Flashing W11-14, Horse Drawn Vehicle Crossing W11-15, Bicycle-Pedestrian Crossing W11-15a & W11-15b, Trail Crossing W11-16, Bear Crossing W11-17, Sheep Crossing W11-18, Bighorn Sheep Crossing W11-19, Donkey Crossing W11-20, Elk Crossing W11-21, Moose Crossing W11-22, Wild horse Crossing W11-25T, Ducks Crossing W11-26aT, Watch for Pelicans W11-26T, Pelicans W12-2, Low Clearance W12-5T, Load Zoned Bridge W14-1T, Road Ends W15-1, Playground W17-3T, Loose Livestock W17-5T, Hospital W17-6T, Military Entrance W17-7T, Military Area W17-11T, Rock Slides W17-12T, Earth Slides W17-14T, Watch for Smoke on Road W17-15T, Watch for Mud on Road W20-3TD, Inspection Station Ahead S3-1, School Bus Stop Ahead S3-2, School Bus Turn Ahead |
B: Decelerate to Indicated Advisory Speed | All warning signs with an advisory speed plaque W1-11T, Curve Blocks View W1-13, Truck Rollover W3-5, S4-5, & S4-5a, Speed Reduction (use speed shown in sign as advisory speed) W7-6, Hill Blocks View W13-2, Exit Speed W13-3, Ramp Speed W13-5T, Curve Speed | W13-6, Exit Curve 25MPH W13-7, Ramp Curve 25MPH W13-8T, XXMPH When Flashing W17-1, Speed Hump |
N/A: No Speed Reduction | W1-1, Turn W1-2, Curve W1-3, Reverse Turn W1-4, Reverse Curve W1-5, Winding Road W1-10 Series, Curve-Intersection W1-11, Hairpin Curve W4-3, Added Lane W4-6, Entering Roadway Added Lane W5-1, Road Narrows W5-2, Narrow Bridge W6-1 & W6-1aT, Divided Highway W6-1bT, Divided Road W6-2 & W6-2aT, Divided Highway Ends W6-2bT, Divided Road Ends W6-3, Two-Way Traffic W6-3aT, Two-Way Traffic on a Three-Lane Road W7-1, Hill W7-1a, Hill with Grade W8-1, Bump W8-2, Dip W8-3, Pavement Ends W8-4, Soft Shoulder W8-5aT, Slow Down on Wet Road W8-7, Loose Gravel | W8-7aT, Loose Sand W8-8, Rough Road W8-9, Low Shoulder W8-9aT, Shoulder Drop Off W8-11, Uneven Lanes W8-12, No Center Line W8-15, Grooved Pavement W8-16, Metal Bridge Deck W8-17, Shoulder Drop Off W8-21, Gusty Winds Area W8-23, No Shoulder W8-25, Shoulder Ends W10-6, Uneven Tracks W10-8, Trains May Exceed 80MPH W10-9, No Train Horn W11-15cT, Watch for Slow Moving Vehicles W17-2T, Rumble Strips W17-4T, Cattle Guard W17-9T, Hitchhikers May Be Escaping Inmates W17-10T, Watch for Low Flying Aircraft W18-1, No Traffic Signs W19-3, Freeway Ends W19-5, All Traffic Must Exit W23-2, New Traffic Pattern Ahead |
N/A: Sign at Hazard | W1-1a & W1-2a, Combination Horizontal Alignment/Advisory Speed W1-6, One Direction Large Arrow W1-7 & W1-7T, Two Direction Large Arrow W1-8, Chevron Alignment W1-9T, One Direction Large Arrow W8-19, Flood Gauge | W12-1, Double Arrow W12-2a, Low Clearance W14-1 & W14-1a, Dead End W14-2 & W14-2a, No Outlet W14-3, No Passing Zone |