Delaware Administrative Code
Title 2 - Transportation
2000 - Department of Transportation
2400 - Division of Transportation Solutions
2402 - Manual on Uniform Traffic Control Devices (MUTCD)
Part 2 - Signs
Chapter 2C - WARNING SIGNS AND OBJECT MARKERS
Section 2C.06 - Horizontal Alignment Warning Signs

Universal Citation: 2 DE Admin Code 2C.06

Current through Register Vol. 28, No. 3, September 1, 2024

Support:

01 A variety of horizontal alignment warning signs (see Figure 2C-1), pavement markings (see Chapter 3B), and delineation (see Chapter 3F) can be used to advise motorists of a change in the roadway alignment. Uniform application of these traffic control devices with respect to the amount of change in the roadway alignment conveys a consistent message establishing driver expectancy and promoting effective roadway operations. The design and application of horizontal alignment warning signs to meet those requirements are addressed in Sections 2C.06 through 2C.15.

Standard:

02 (DE Revision) 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 on the tangent approach to the curve and the horizontal curve's advisory speed.

Guidance:

02A (DE Revision) The provisions of Table 2C-5 that recommend or require the use of certain signs or plaques should be applied only where the advisory speed for the curve is less than the posted or statutory speed limit on the tangent approach to the curve.

Option:

02B (DE Revision) Where an advisory speed determined in accordance with Section 2C.08 equals or exceeds the posted or statutory speed limit, horizontal alignment warning signs, excluding Advisory Speed plaques, may be installed based upon engineering judgment.

03 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.

Support:

03A (DE Revision) FHWA's Interpretation Letter 2(09)-2 (I) - Determination of Speed Differential for Curve Warning Signs and Plaques clarifies data collection requirements recognizing that it is unrealistic to collect data in advance of every curve where Table 2C-5 is applied. Table 2C-4. Guidelines for Advance Placement of Warning Signs

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 condition
03 104 204 304 404 504 604 704
20 mph 225 ft 100 ft6 N/A5 - - - - - -
25 mph 325 ft 100 ft6 N/A5 N/A5 - - - - -
30 mph 460 ft 100 ft6 N/A5 N/A5 - - - - -
35 mph 565 ft 100 ft6 N/A5 N/A5 N/A5 - - - -
40 mph 670 ft 125 ft 100 ft6 100 ft6 N/A5 - - - -
45 mph 775 ft 175 ft 125 ft 100 ft6 100 ft6 N/A5 - - -
50 mph 885 ft 250 ft 200 ft 175 ft 125 ft 100 ft6 - - -
55 mph 990 ft 325 ft 275 ft 225 ft 200 ft 125 ft N/A5 - -
60 mph 1,100 ft 400 ft 350 ft 325 ft 275 ft 200 ft 100 ft6 - -
65 mph 1,200 ft 475 ft 450 ft 400 ft 350 ft 275 ft 200 ft 100 ft6 -
70 mph 1,250 ft 550 ft 525 ft 500 ft 450 ft 375 ft 275 ft 150 ft -
75 mph 1,350 ft 650 ft 625 ft 600 ft 550 ft 475 ft 375 ft 250 ft 100 ft6

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 Sight 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 Sight Distance, providing a PRT of 2.5 seconds, a deceleration rate of 11.2 feet/second2, minus the sign legibility distance of 180 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 location is 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.

Table 2C-4A. Guidelines for Minimum Spacing between Warning Signs

(Delaware Revision)

Posted or 85thPercentileSpeed Minimum Spacing Posted or 85thPercentileSpeed Minimum Spacing
20 mph 100 ft 45 mph 300 ft
25 mph 100 ft 50 mph 400 ft
30 mph 100 ft 55 mph 500 ft
35 mph 150 ft 60 mph 600 ft
40 mph 200 ft 65 mph 700 ft

Table 2C-5. Horizontal Alignment Sign Selection

(Delaware Revision)

Type of Horizontal Alignment Sign Difference Between Approach Speed and Curve 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 series) (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

* Difference Between Approach Speed and Curve Advisory Speed is defined as the difference in speed between the posted or statutory speed limit or 85th-percentile speed on the tangent approach to the curve and the advisory speed for the curve.

Note: Required means that the sign and/or plaque shall be used, recommended means that the sign and/or plaque should be used, and optional means that the sign and/or plaque may be used.

See Section 2C.06 for roadways with less than 1,000 AADT.

Disclaimer: These regulations may not be the most recent version. Delaware may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
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