Work Zone - Appendix K

Appendix K: Temporary Sign Design Guidelines

(Added 12/3/2020)

Overview

This document is to be followed when using SignCad to design temporary special signs for use during construction. The guidelines and examples listed below are intended to maximize the size of the legend, while keeping the sign size small enough to meet space limitations and post size requirements. Signs designed must meet all current crash testing requirements.

General Guidelines

• The sign design should be based on the space available, (i.e shoulder width, slope condition, etc) for the sign, taking into account the sign support system to be used.
• It is desirable to have driven special signs not exceed a 4’ × 8’ sheet of plywood. If necessary, it is allowable to increase the length to 10 feet.
• Signs mounted on two temporary portable supports or barrier mounted signs must be 20 sft or less in size.
• Signs mounted on a single steel portable support must be 9 sft or less in size.
• Start design using the maximum text size requirements. (i.e. using a 6”D letter size will have the same width as a 7”C letter size because of the stroke width. However, the 7”C letter size is preferred if sign height is not an issue).
• Limit the sign message to no more than three lines of text. An additional supplemental message, such as “FOLLOW DETOUR”, may be added at the bottom of the sign. Separate the supplemental message from the main body of the sign with a horizontal line that is the same thickness as the sign border.
• Sign widths should be designed to increments of a ½ foot. Post types will vary depending upon the size of the sign as determined by the Sign Support Selection Chart (SIGN-150-D.pdf).
• Sign heights should be in ½ foot increments, with the exception that separate 15 inch tall signs are allowable.
• If both the width and the height of the sign are greater than 4 feet, the sign will require a horizontal splice. Design the sign so splices are not in the middle of a legend or border. 
• Vertical splices are not allowed.  Horizontal spliced panels should be designed in ½ foot increments.  (i.e. a 78” × 54” sign would need two panels 78” wide.  An acceptable option would be a 78” × 36” panel and a 78” × 18” panel if the seam between the panels does not go through a legend or border).

Letter Sizes

Non-Freeway
Maximum	7"D
	7"C
	6"D
	6"C
	5"D
Minimum	7"C

Freeway
Maximum	8"D
	8"C
	7"D
Minimum	7"C

Vertical Spacing Guidelines

• Vertical spacing between text lines may range from 2 inches less than the text height to the text height. Vertical spacing between text lines is desirable to be 2 inches less than the text size. (i.e. if using 7 inch text height, 5 inch spacing between lines is desirable but the spacing may increase to 7 inches).
• Signs with multiple lines of text should have the vertical spacing between the text and the top and bottom edge of the sign and the line separating the supplemental message equal the text height but may be reduced by up to 2 inches.
• Signs with a single line of text should have the vertical spacing between the text and the top and bottom edges of the sign be 3 inches less than the text height.
• Vertical spacing between an M1 series route shield and the top/bottom edge of the sign or text above/below the shield should range from 3 inches less than the text height to the text height.

Horizontal Spacing Guidelines

• Horizontal spacing between words in a line of text should equal the text height but may be reduced by up to 2 inches (i.e. the spacing between words with 8-inch text may be reduced to 6 inches).
• Horizontal spacing between text and right or left border should equal the text height but may be reduced by up to 2 inches.
• Letter spacing may be reduced to no less than 75% spacing.

Sign Size Reduction

Begin the sign design using the maximum letter size and then evaluate the sign size to see if it fits (or can be adjusted to fit) on a 4’ × 8’ piece of plywood.

If the sign height needs to be reduced, begin by reducing the vertical spacing between the text lines and between the top and bottom borders and any supplemental border line. If further height reduction is necessary, then reduce the text height. Splices may be required to meet the necessary sign height.

If the sign width needs to be reduced, follow the steps below.

• Step 1 - Begin sign design using the maximum text size and the recommended horizontal spacing. Evaluate the sign. If too wide, proceed to Step 2.
• Step 2 - Reduce horizontal space between text and left/right borders by a maximum of 2 inches. Evaluate width. If too wide keep this change and proceed to Step 3.
• Step 3 - Reduce horizontal space between words by a maximum of 2 inches. Evaluate width. If too wide keep these changes and proceed to Step 4.
• Step 4 - Reduce horizontal spacing between letters to no less than 75% spacing. Evaluate width. If too wide proceed to Step 5.
• Step 5 - Reset the spacing between the borders, words, and letters. Change the text size from "D" text to "C" text. Evaluate width. If too wide proceed to Step 6.
• Step 6 - Repeat Steps 2-4 using the "C" text. Evaluate the size after each step. If too wide proceed to Step 7.
• Step 7 - Reset the spacing between the borders, words, and letters. Start the process over at step 2, using text that is 1" smaller. Continue process until width requirements are met.

If the text height changed when reducing the width, go back and check the vertical spacing, adjust as necessary.

Supplemental Road Name Plaques with Diamond Signs

• Supplemental signs placed below a 4’ × 4’ diamond sign on two 3# posts must be 4 sft or less so that the total square footage does not exceed 20sft.
• Supplemental signs should be uniform under the 4’ × 4’ diamond sign in order to spread the width of the two posts (i.e., 48 inch × 12 inch).
• Supplemental route marker signs placed below a 4’ × 4’ diamond sign must be less than 4 sft including the cardinal direction sign if used.

Detour Route Clusters

• Detour route sign clusters with M4-8, cardinal direction, route marker shield, and directional arrow must not exceed 9 sft on a single post.

Supplemental Road Name Plaques with M4-9 Signs

• Supplemental road name sign sizes above a standard M4-9 detour sign may be 12 inches, 15 inches, or 18 inches in height.
• Signs must be kept below 9 sft for single post installations and 20 sft for double post installations.
• The minimum width of the supplemental sign is the width of the M4-9 sign below it. In general, the maximum width of the supplemental sign should be no more than 6 inches greater than the width of the M4-9 sign below it, so that there is only a 3-inch overhang on each side of the M4-9 unless the word is too long, in which case additional length may be added.
• A second line may be used for a second route name or direction as long as the signs are kept below the 9 sft or 20 sft requirements listed above.
• Do not add a road name suffix (i.e., Rd, Ave, Blvd, etc..) unless the road name is a common name or city, village, etc.
• The first letter of a cardinal direction should be the same size as the remaining letters (for example, all letters in NORTH should be the same size)

Temporary Route Marker Shield Sizes

Use standard M1 series route shields and sizes for state trunk lines as defined in the standard sign manual.

If the total special sign size is too small to fit a standard route marker size, then smaller shields may be used. Avoid spelling out the trunk line number (i.e. Do not spell out “I-96”. Use an M1-1 (96) shield).

Borders

• Border sizes and radii should correspond with the appropriate sign type: W, M, I, D, E series signs in the Standard Highway Signs Manual (Traffic Signing).

Sheeting Sizes

• Standard sheeting sizes are 24”, 30”, 36”, and 48” in width.

Overhead Signs

• Overhead letter sizes should be 12”D maximum and 10”D minimum.
• Overhead sign covers should be black on orange when conveying a message and orange when a blank cover is used.

Additional References

Support Hole Placement Sign Support Index

Special Sign Design Process

Example 1

Step 1 - Create a sign for use on the freeway

• Start with 8"D for freeway use
• Set default sign size increment to 6"

INSERT PICTURE

• SignCad default shows sign is too big for 4' × 8' plywood. Would require 10' long plywood to meet width, and a splice to meet height. Try to downsize the sign.

Step 2 - Try to reduce sign size to fit into a 96" × 48" (4' × 8' plywood)

• Start with reducing text size from 8" to 7"D (to not exceed 48" height for plywood)

INSERT PICTURE

• Check vertical spacing
  • Vertical spacing meets the guidelines, but vertical spacing for top and bottom border and horizontal line are not balanced (i.e. 6.5" from text to top/bottom edge of sign, but 5" from text to top/bottom of horizontal lines).

Step 3 - Adjust vertical spacing to meet guidelines

• Vertical spacing for horizontal line increased from 4" to 4.5" to have a total of 5.5" between text and edge of horizontal line
• Vertical Spacing