Delaware Administrative Code
Title 2 - Transportation
2000 - Department of Transportation
2400 - Division of Transportation Solutions
2402 - Manual on Uniform Traffic Control Devices (MUTCD)
Part 6 - Temporary Traffic Control
Chapter 6C - TEMPORARY TRAFFIC CONTROL ELEMENTS
Section 6C.04 - Advance Warning Area
Current through Register Vol. 28, No. 3, September 1, 2024
Support:
01 The advance warning area is the section of highway where road users are informed about the upcoming work zone or incident area.
Option:
02 The advance warning area may vary from a single sign or high-intensity rotating, flashing, oscillating, or strobe lights on a vehicle to a series of signs in advance of the TTC zone activity area.
Guidance:
03 Typical distances for placement of advance warning signs on freeways and expressways should be longer because drivers are conditioned to uninterrupted flow. Therefore, the advance warning sign placement should extend on these facilities as far as 1/2 mile or more.
| Table 6C-1. Recommended Advance Warning Sign Minimum Spacing (Delaware Revision) | ||||
| Road Type | Distance Between Signs** | |||
| A | B | C | ||
| Urban (low speed)* | 100 feet | 100 feet | 100 feet | |
| Urban (high speed)* | 350 feet | 350 feet | 350 feet | |
| Rural | 500 feet | 500 feet | 500 feet | |
| Interstate / Expressway / Freeway | 1,000 feet | 1,640 feet | 2,640 feet | |
| *** | 40 mph or less is "low speed" and over 40 mph is "high speed" on state-maintained roadways. The column headings A, B, and C are the dimensions shown in Figures 6H-1 through 6H-46. The A dimension is the distance from the transition or point of restriction to the first sign. The B dimension is the distance between the first and second signs. The C dimension is the distance between the second and third signs. (The "first sign" is the sign in a three-sign series that is closest to the TTC zone. The "third sign" is the sign that is farthest upstream from the TTC zone.) | |||
04 On urban streets, the effective placement of the first warning sign in feet should range from 4 to 8 times the speed limit in mph, with the high end of the range being used when speeds are relatively high. When a single advance warning sign is used (in cases such as low-speed residential streets), the advance warning area can be as short as 100 feet. When two or more advance warning signs are used on higher-speed streets, such as major arterials, the advance warning area should extend a greater distance (see Table 6C-1).
05 Since rural highways are normally characterized by higher speeds, the effective placement of the first warning sign in feet should be substantially longer-from 8 to 12 times the speed limit in mph. Since two or more advance warning signs are normally used for these conditions, the advance warning area should extend 1,500 feet or more for open highway conditions (see Table 6C-1).
06 The distances contained in Table 6C-1 are approximate, are intended for guidance purposes only, and should be applied with engineering judgment. These distances should be adjusted for field conditions, if necessary, by increasing or decreasing the recommended distances.
Support:
07 The need to provide additional reaction time for a condition is one example of justification for increasing the sign spacing. Conversely, decreasing the sign spacing might be justified in order to place a sign immediately downstream of an intersection or major driveway such that traffic turning onto the roadway in the direction of the TTC zone will be warned of the upcoming condition.
Option:
08 Advance warning may be eliminated when the activity area is sufficiently removed from the road users' path so that it does not interfere with the normal flow.
