Road Signs: Sign Categories
16 questions in the bank cover this topic. Everything below is drawn from the sources those questions cite.
Sources: MUTCD 11th Ed. Section 1D.05, MUTCD 11th Ed. Section 2B.01, MUTCD 11th Ed. Section 2C.01, MUTCD 11th Ed. Section 2C.02
What you need to know
Yellow means warning under MUTCD 1D.05 and the diamond is the warning series under Table 2A-1.
Both signals agree: it informs you of a condition, it does not create a rule you can be cited for breaking. It tells you about a condition ahead without imposing a legal requirement.
The general meaning of the 13 colors shall be as follows: A. Black—regulation B. Blue—road-user services guidance, tourist information, and evacuation route C. Brown—recreational and cultural interest area guidance D. Coral—reserved for future designation (see Paragraph 4 of this Section) E. Fluorescent Pink—incident management F. Fluorescent Yellow-Green—pedestrian warning, bicycle warning, playground warning, school bus warning, and school warning G. Green—indicated movements or actions permitted and direction guidance H. Light Blue—reserved for future designation (see Paragraph 4 of this Section) I. Orange—temporary traffic control J. Purple—restricted to use only by vehicles with registered electronic toll collection (ETC) accounts K. Red—stop or prohibition L. White—regulation M. Yellow—warning
MUTCD 11th Ed. Section 1D.05
The diamond still means warning, but MUTCD 1D.05 assigns orange to temporary traffic control.
So the hazard is a work zone or similar temporary condition, which usually means workers, equipment and a changed road layout rather than a permanent curve or grade. Orange means the condition is temporary rather than a permanent feature of the road.
The general meaning of the 13 colors shall be as follows: A. Black—regulation B. Blue—road-user services guidance, tourist information, and evacuation route C. Brown—recreational and cultural interest area guidance D. Coral—reserved for future designation (see Paragraph 4 of this Section) E. Fluorescent Pink—incident management F. Fluorescent Yellow-Green—pedestrian warning, bicycle warning, playground warning, school bus warning, and school warning G. Green—indicated movements or actions permitted and direction guidance H. Light Blue—reserved for future designation (see Paragraph 4 of this Section) I. Orange—temporary traffic control J. Purple—restricted to use only by vehicles with registered electronic toll collection (ETC) accounts K. Red—stop or prohibition L. White—regulation M. Yellow—warning
MUTCD 11th Ed. Section 1D.05
MUTCD 1D.05 reserves fluorescent yellow-green for pedestrian, bicycle, playground, school bus and school warnings.
The unusual color exists so warnings about vulnerable people are not lost among ordinary yellow signs.
The general meaning of the 13 colors shall be as follows: A. Black—regulation B. Blue—road-user services guidance, tourist information, and evacuation route C. Brown—recreational and cultural interest area guidance D. Coral—reserved for future designation (see Paragraph 4 of this Section) E. Fluorescent Pink—incident management F. Fluorescent Yellow-Green—pedestrian warning, bicycle warning, playground warning, school bus warning, and school warning G. Green—indicated movements or actions permitted and direction guidance H. Light Blue—reserved for future designation (see Paragraph 4 of this Section) I. Orange—temporary traffic control J. Purple—restricted to use only by vehicles with registered electronic toll collection (ETC) accounts K. Red—stop or prohibition L. White—regulation M. Yellow—warning
MUTCD 11th Ed. Section 1D.05
MUTCD 1D.05 assigns blue to road-user services guidance and tourist information, and brown to recreational and cultural interest area guidance.
So fuel and hospital are blue, and a national park or historic site is brown. Blue covers fuel, food and hospitals; brown covers recreational and cultural sites.
The general meaning of the 13 colors shall be as follows: A. Black—regulation B. Blue—road-user services guidance, tourist information, and evacuation route C. Brown—recreational and cultural interest area guidance D. Coral—reserved for future designation (see Paragraph 4 of this Section) E. Fluorescent Pink—incident management F. Fluorescent Yellow-Green—pedestrian warning, bicycle warning, playground warning, school bus warning, and school warning G. Green—indicated movements or actions permitted and direction guidance H. Light Blue—reserved for future designation (see Paragraph 4 of this Section) I. Orange—temporary traffic control J. Purple—restricted to use only by vehicles with registered electronic toll collection (ETC) accounts K. Red—stop or prohibition L. White—regulation M. Yellow—warning
MUTCD 11th Ed. Section 1D.05
MUTCD 1D.05 assigns both white and black to regulation, and the rectangle serves the regulatory series in Table 2A-1.
Speed limits and lane use restrictions take this form, and they are enforceable. The manual assigns both white and black to regulation.
The general meaning of the 13 colors shall be as follows: A. Black—regulation B. Blue—road-user services guidance, tourist information, and evacuation route C. Brown—recreational and cultural interest area guidance D. Coral—reserved for future designation (see Paragraph 4 of this Section) E. Fluorescent Pink—incident management F. Fluorescent Yellow-Green—pedestrian warning, bicycle warning, playground warning, school bus warning, and school warning G. Green—indicated movements or actions permitted and direction guidance H. Light Blue—reserved for future designation (see Paragraph 4 of this Section) I. Orange—temporary traffic control J. Purple—restricted to use only by vehicles with registered electronic toll collection (ETC) accounts K. Red—stop or prohibition L. White—regulation M. Yellow—warning
MUTCD 11th Ed. Section 1D.05
The MUTCD's own reason is prompt recognition.
A driver should be able to classify a sign before reading it, which is why color and shape carry meaning independently of the legend.
Standardized colors and shapes are specified so that the several classes of traffic signs can be promptly
MUTCD 11th Ed. Section 1D.05
MUTCD 1D.05 assigns red to stop or prohibition and nothing else.
That is why DO NOT ENTER and WRONG WAY are red, and why the circle-and-slash over a prohibited movement is red.
The general meaning of the 13 colors shall be as follows: A. Black—regulation B. Blue—road-user services guidance, tourist information, and evacuation route C. Brown—recreational and cultural interest area guidance D. Coral—reserved for future designation (see Paragraph 4 of this Section) E. Fluorescent Pink—incident management F. Fluorescent Yellow-Green—pedestrian warning, bicycle warning, playground warning, school bus warning, and school warning G. Green—indicated movements or actions permitted and direction guidance H. Light Blue—reserved for future designation (see Paragraph 4 of this Section) I. Orange—temporary traffic control J. Purple—restricted to use only by vehicles with registered electronic toll collection (ETC) accounts K. Red—stop or prohibition L. White—regulation M. Yellow—warning
MUTCD 11th Ed. Section 1D.05
MUTCD 1D.05 groups evacuation route with road-user services guidance and tourist information under blue.
Green is for permitted movements and direction guidance generally, not for evacuation specifically.
The general meaning of the 13 colors shall be as follows: A. Black—regulation B. Blue—road-user services guidance, tourist information, and evacuation route C. Brown—recreational and cultural interest area guidance D. Coral—reserved for future designation (see Paragraph 4 of this Section) E. Fluorescent Pink—incident management F. Fluorescent Yellow-Green—pedestrian warning, bicycle warning, playground warning, school bus warning, and school warning G. Green—indicated movements or actions permitted and direction guidance H. Light Blue—reserved for future designation (see Paragraph 4 of this Section) I. Orange—temporary traffic control J. Purple—restricted to use only by vehicles with registered electronic toll collection (ETC) accounts K. Red—stop or prohibition L. White—regulation M. Yellow—warning
MUTCD 11th Ed. Section 1D.05
MUTCD 1D.05 separates incident management, which is pink, from temporary traffic control, which is orange.
The distinction tells a driver whether the situation was set up in advance or has just happened, which affects how predictable the layout will be.
The general meaning of the 13 colors shall be as follows: A. Black—regulation B. Blue—road-user services guidance, tourist information, and evacuation route C. Brown—recreational and cultural interest area guidance D. Coral—reserved for future designation (see Paragraph 4 of this Section) E. Fluorescent Pink—incident management F. Fluorescent Yellow-Green—pedestrian warning, bicycle warning, playground warning, school bus warning, and school warning G. Green—indicated movements or actions permitted and direction guidance H. Light Blue—reserved for future designation (see Paragraph 4 of this Section) I. Orange—temporary traffic control J. Purple—restricted to use only by vehicles with registered electronic toll collection (ETC) accounts K. Red—stop or prohibition L. White—regulation M. Yellow—warning
MUTCD 11th Ed. Section 1D.05
MUTCD 2B.01 defines regulatory signs by their legal function.
That is the key difference from a warning sign: a regulatory sign creates a requirement you can be cited for breaking. Regulatory signs state a requirement, unlike warning signs.
Regulatory signs shall be used to inform road users of selected traffic laws or regulations and to indicate the applicability of the legal requirements.
MUTCD 11th Ed. Section 2B.01
MUTCD 2B.01 requires placement at or near the point of application, and the sign must clearly indicate the requirement with adequate visibility and legibility to obtain compliance.
Regulatory signs shall be installed at or near where the regulations apply.
MUTCD 11th Ed. Section 2B.01
MUTCD 2B.01 requires retroreflection or illumination.
2C.01 imposes the same on warning signs, so both classes must be readable after dark.
Regulatory signs shall be retroreflective or illuminated
MUTCD 11th Ed. Section 2B.01
MUTCD 2C.02 specifies the diamond, described precisely as a square with one diagonal vertical, with black legend and border on yellow.
Exceptions exist but this is the default. The border is black as well.
all warning signs shall be diamond-shaped (square with one diagonal vertical) with a black legend and border on a yellow background
MUTCD 11th Ed. Section 2C.02
MUTCD 2C.01 gives a behavioural reason rather than a cost one.
A driver who learns that most warning signs mean nothing stops reacting to the ones that do.
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.
MUTCD 11th Ed. Section 2C.01
MUTCD 2C.01 says remove or cover it.
This follows directly from the disrespect point: a sign warning of something that is not there teaches drivers to ignore 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.
MUTCD 11th Ed. Section 2C.01
MUTCD 2C.01 requires an engineering basis.
This is why you cannot simply request a warning sign be erected at a location that worries you.
The use of warning signs shall be based on an engineering study or on engineering judgment.
MUTCD 11th Ed. Section 2C.01
Check yourself
- What is a yellow diamond-shaped sign, and what does it do?
- What is the meaning of an orange diamond-shaped sign rather than a yellow one?
- What four kinds of hazard does a fluorescent yellow-green diamond warn about?
- What is on a blue sign and what is on a brown sign?
- What is normally conveyed by a white rectangular sign with a black legend?
- Why does the manual standardise the sign colors and shapes you have to read?
- What are the only two meanings the manual allows a red sign to carry?
- What is the color that marks a designated evacuation route?
- What is the difference between fluorescent pink signs and orange ones?
- What should you take a regulatory sign to be telling you?
- Where will you find a regulatory sign installed?
- What is the visibility requirement that applies to a regulatory sign at night?
- The standard design of a warning sign is ______.
- Why does the manual say the warning signs you see should be kept to a minimum?
- What is required of a warning sign for a seasonal condition once it passes?
- What is the basis on which a decision to install a warning sign must rest?
Answers are in the practice test for this topic.