A: A single solid yellow centerline for bi-directional traffic does not have any legal definition and introduces ambiguity to the motorist. The practice to provide a single solid yellow centerline on rural roads, residential streets or narrow roadways is not appropriate and the additional minor cost of a second longitudinal line instead of one is not a valid justification for compromising any legal code associated with traffic operations or traffic control devices. Further, individual State laws may define the legal connotation of the single solid yellow line, but these legal definitions vary from state to state thereby resulting in non-uniformity nationwide.

The FHWA is not aware of any association where a single solid yellow centerline indicates any consistent procedure, enforcement, or achieves positive results in any specific motorist behavior. In fact, the traveling public consistently demonstrates that the single solid yellow centerline does not communicate adequately in terms of whether passing is allowed or prohibited in one or both directions.

The double yellow centerline system is well established and collectively understood by road users. Using a single yellow center line would only save 6-8 inches in width compared to a double line and, even on narrow roads, this savings is not considered to be significant enough to warrant compromising the well-understood double-line system.

Return to Top

Q: Is it illegal to cross a double yellow centerline on a road when making a left turn into a private driveway?

A: Usually this is not illegal, but it is necessary to check individual State and/or local laws to be sure. The MUTCD calls for "two-direction no-passing zone" centerline markings to separate opposing directions of traffic on undivided multilane roads. That is, the double yellow line separates the opposing flows and prohibits travel to the left of the centerline for "passing" (i.e., overtaking a slower moving vehicle) in either direction. The text in the MUTCD does not in itself preclude left turns into driveways. That is an issue that can vary from state to state.

The Uniform Vehicle Code, which is a model for State and local traffic ordinances that is published by the National Committee on Uniform Traffic Laws and Ordinances (www.ncutlo.org), states in section 11-301(c) that on any two-way roadway having four or more lanes of moving traffic no vehicle shall be driven to the left of the centerline, and "this shall not be construed as prohibiting the crossing of the centerline in making a left turn into or from an alley, private road, or driveway." Most States have patterned their laws on the Uniform Vehicle Code but there are a very few States and/or local jurisdictions whose traffic laws or ordinances make it illegal to make a left turn across any double yellow line into a driveway. Also, State laws often prescribe certain conditions, such as obstruction of lanes, in which it is legal to drive to the left of the centerline.

Return to Top

Q: My agency is considering using internally-illuminated raised pavement markers (IIRPM) to supplement center line and lane line markings through a particularly severe horizontal curve to help road users navigate the curve. Is it allowable to flash those IIRPMs when approaching vehicles exceed a given speed threshold?

A: No, not without FHWA granting experimentation approval under the provisions of Section 1A.10. That is because Section 3B.11 states that, when used, IIRPM shall be steadily illuminated and shall not be flashed. Such markers, when flashed, are considered In-Roadway Warning Lights and are governed by the provisions of Chapter 4N, which limits the use of such flashing devices to crosswalks across uncontrolled approaches.

Return to Top

Q: Given the answer to the previous question, could my agency set up the IIRPMs to be normally "off" and only turn them on (in a steadily-illuminated mode) for a certain number of seconds when a vehicle is detected approaching the curve?

A: Yes. There is no requirement in the MUTCD that IIRPMs must be "on" at all times. Turning them on only when "needed" (i.e., when vehicles are present) is consistent with MUTCD basic principles.

Return to Top

Colored Pavement

Q: What are the approved uses for red-colored pavement?

A: There is none. Red-colored pavement for use as a traffic control device is not permitted. This is provided in Paragraph 3 of Section 3G.01. Red bricks or stamped red pavers in a crosswalk is an aesthetic treatment and is not a traffic control device.

Red-colored pavement may be used only with FHWA granting experimentation approval under the provisions of Section 1A.10.

Return to Top

Q: What are the approved uses of green-colored pavement?

A: Green-colored pavement is only approved for use in bicycle lanes in accordance with Interim Approval 14, and is not approved for general use in any bicycle facility. Use of green-colored pavement for other bicycle facilities other than bicycle lanes may be used only with FHWA granting experimentation approval under the provisions of Section 1A.10. More information is provided here.

Agencies sometimes use green-colored pavement to supplement, fill in, or outline parking areas or parking stalls for electric vehicle charging stations in order to express the agency's commitment to environmentally friendly initiatives. This practice is not in compliance with Interim Approval 14 and the FHWA is not considering this alternative use of green-colored pavement for experimentation. Although the applicability of the MUTCD may be limited in certain settings involving parking stalls, agencies are encouraged to adhere to the MUTCD with respect to disallowing green-colored pavement in parking facilities for the purpose of maintaining uniformity among similar facilities.

Return to Top

Q: What are the approved uses of purple-colored pavement?

A: There is none. Purple as a colored pavement may also not be used on a toll facility in accordance with Paragraph 3 of Section 3G.01. Purple may be used as a longitudinal marking to flank a longitudinal lane line as provided in Paragraphs 5 and 6 in Section 3G.01.

Purple-colored pavement may be used only with FHWA granting experimentation approval under the provisions of Section 1A.10.

Return to Top

Q: Does the MUTCD allow intersection murals or widespread application of artwork to the street?

A: Exclusive of a crosswalk that may be present, intersection murals and street artwork are not traffic control devices and the MUTCD most likely does not directly apply. Intersection murals and street artwork then become a right-of-way issue. Paragraph (b) of 23 CFR 1.23 provides that all property within the right-of-way boundaries shall be devoted exclusively to public highway purposes. Intersection murals and street artwork have a potential to compromise motorist safety by interfering with, detracting from, or obscuring official traffic control devices. They can also encourage road users—especially bicycles and pedestrians—to directly participate in the design, loiter in the street, or give reason to not vacate the street in an expedient or predictable manner. For these reasons, exceptions for intersection murals and street art are not made in accordance with Paragraph (c) of 23 CFR 1.23.

Past practices of intersection murals and street art have compromised the veracity of the crosswalk. The crosswalk is a traffic control device and is under the authority of the MUTCD. Guidance for aesthetic treatments in crosswalks is provided here. Discussion in the memo on the potential of crosswalk art as a source of distraction could be analogous to intersection art and street murals.

Return to Top

Crosswalks

Q: What are the warrants for installing a marked crosswalk at a midblock location?

A: Section 3B.18 of the 2009 MUTCD states: "Crosswalk lines should not be used indiscriminately. An engineering study should be performed before they are installed at locations away from a traffic control signal or an approach controlled by a STOP or YIELD sign" and it describes the factors that should be considered in the study. Section 3B.18 also gives very specific guidance about where a new crosswalk should not be installed across an uncontrolled approach on roads with 4 or more lanes and speeds of over 40 mph without other measures designed to reduce traffic speeds, shorten crossing distances, enhance driver awareness of the crossing, and/or provide active warning of pedestrian presence. This guidance is based on a study performed for FHWA in 2002 by Zegeer, Stewart, and Huang entitled "Safety Effects of Marked vs Unmarked Crosswalks at Uncontrolled Locations: Executive Summary and Recommended Guidelines", which may be viewed and downloaded at: http://safety.fhwa.dot.gov/ped_bike/docs/cros.pdf.

Return to Top

Q: Can I put any design or collection of art treatments in a crosswalk as long as the transverse white lines are present?

A: No. The FHWA has consistently stated since 1984 through eight Official Interpretations that nothing except an aesthetic treatment is allowed between the white transverse lines of a crosswalk. If non-retroreflective colored pavement, including bricks and other types of patterned surfaces, is used as a purely aesthetic treatment and is not intended to communicate a regulatory, warning, or guidance message to road users, the colored pavement is not considered to be a traffic control device, even if it is located between the lines of a crosswalk. Additional guidance and a summary of past Official Interpretations on this topic is summarized here.

Return to Top

Q: My city is trying to make the downtown area more aesthetically pleasing and pedestrian-friendly. We are installing brick sidewalks, benches, trees, and other "streetscaping" features along the business district streets. As part of the project, we plan to install brick pavers or other similar treatments to serve as the crosswalks at intersections. Can this type of crosswalk meet the MUTCD requirements?

A: The brick pavers alone would not constitute a legal crosswalk. White, retroreflective pavement marking lines must be used to officially establish a legal crosswalk. As discussed in Chapter 3G of the 2009 MUTCD (Colored Pavements), brick pavers and colored decorative paving treatments that simulate brick or other patterns may be used between the white crosswalk lines. However, colors that degrade the contrast of the white crosswalk lines with the adjoining areas and colors that might be mistaken by road users as a traffic control application or might otherwise constitute a distraction should not be used for this purpose. So, for example, the standard colors of red and yellow used for STOP signs and warning signs should not be used, nor should the colors white and yellow as these are used for pavement marking lines. Also, retroreflective colored pavements of any color or pattern are prohibited between crosswalk lines.

Return to Top

Contrast Striping

Q: When black markings are used to provide enhanced contrast for white or yellow pavement markings, what widths and patterns of black markings should be used?

A: The MUTCD is silent on this, other than saying that black may be used with standard color markings to increase contrast with light colored pavements. There are many different practices around the U.S. to highlight broken lines, some States put 1″-2″ black stripes along both outside edges of the line segments, some States fill in the entire gap between line segments with a normal width black line, some put a length of normal width black line in front of the line segment, and some put the black after the line segment. For more information, a study by the Texas Transportation Institute by Carlson, Miles, Pike, and Park entitled "Evaluation of Wet-Weather and Contrast Pavement Marking Applications: Final Report" may be viewed and downloaded at: http://d2dtl5nnlpfr0r.cloudfront.net/tti.tamu.edu/documents/0-5008-2.pdf.

Return to Top

Longitudinal Markings

Q: Does a solid white lane line prohibit crossing to change lanes?

A: MUTCD Section 3B.04 says to use a single solid white line to "discourage" crossing the lane line and a double white line to prohibit crossing it. A single solid white line is used for a variety of lines that drivers should be discouraged from crossing in "normal" situations but which drivers do need to cross in some situations. An example is the "edge line"---the line that separates the rightmost travel lane from the shoulder. The single solid white line discourages crossing onto the shoulder but does not prohibit it because it is sometimes desirable and/or necessary to cross it in some situations, such as an emergency stop. The MUTCD sets the national standards for pavement markings, but it does not establish what the laws of the individual States may define as the legal meanings of various types of lines in each State. Some States may have laws that prohibit crossing a single solid white line in specific circumstances. Some states also have laws that go beyond just the meaning of the lines, by making certain driving maneuvers illegal under certain situations regardless of the markings, such as changing lanes when it is "unsafe to do so".

Return to Top

Q: Why does the MUTCD recommend a 3:1 ratio for gap length and skip length for a broken lane line? What research is this based on?

A: The 1971 edition of the MUTCD provided a ratio of 3:5 based on long-standing practice by the States for rural highways using 15-foot skips and 25-foot gaps to suggest a total length of 40 feet. Section 205 of the Highway Safety Act in 1973 established a pavement marking demonstration program to enable the States to generally improve the pavement markings to all highways. As a result, this MUTCD language became the normal for States acting to comply with Section 205.

The energy crisis of 1973-74 caused the cost of traffic paint to double or triple and suppliers were unable to furnish most States enough paint to accomplish basic pavement marking operations. Because of the materials shortage and the need to comply with Section 205, several States experimented with alternative skip-gap pattern lengths. In the interest of conserving paint and providing a device that would convey the same meaning as the 3:5 ratio, or "flicker rate" on rural roads and freeways, research concluded that the 10:30 ratio provided logistical and financial benefits, with no discernible negative effects on safety. Thus, most States adopted the 10:30 ratio or switched to that ratio to achieve financial savings.

The National Advisory Committee on Uniform Traffic Control Devices adopted the ratio at a meeting in the spring of 1974 resulting in a change to Section 3A-6 of the 1978 MUTCD.

Return to Top

Q: Why doesn't the MUTCD provide for a dotted lane line, rather than a normal broken lane line, on the approach to a lane-reduction transition? Isn't this another example of a "non-continuing lane" that would be appropriate for use of a dotted lane line?

A: Although the FHWA originally proposed to also require a dotted lane line approaching a lane-reduction transition, that proposal was not adopted in the final rule for the 2009 MUTCD. FHWA determined that lane-reduction transitions may be significantly different from lane drop situations, because a lane-reduction transition occurs between interchanges or between intersections and thus all vehicles in the ending lane must merge into the adjacent lane, while at a lane drop, vehicles that are unable to leave the lane do have the ability to stay in the lane and proceed to exit or turn. Also, the lack of any lane line marking for ¾ of the distance from the Lane Ends warning sign to the point where the lane-reduction taper begins (as the current standard calls for) may help to reinforce the need to merge early rather than waiting to the last moment. Additional experimentation and research is needed to determine whether the use of a dotted lane line for some distance in advance of the lane-reduction transition is preferable to the longstanding standard marking pattern for a lane-reduction transition.

Return to Top

Passing Sight Distance

Q: What are the minimum passing sight distances for no-passing zone markings in Table 3B-1 in the MUTCD based on? Where did they come from?

A: There is support to suggest that these values were those presented to the 1940 AASHO Policy on marking no-passing zones. In addition, the first edition of the Traffic Engineering Handbook by ITE from 1941 provided that in some States, particularly in generally level terrain, the majority of the highways are considered to have a uniform design speed for the purpose of establishing no-passing zones. A fixed minimum sight distance (frequently 500 to 800 feet) was then generally agreed upon. This suggests that at all times motorists should be subject to a minimum of 500 feet of sight distance based on existing practice at that time.

Return to Top

Q: Why do the MUTCD and the AASHTO Green Book have different values for passing sight distance?

A: Like many aspects of highway design, the values used for design of a new facility are often more conservative than what operating agencies find to be "reasonable minimums" for actual operating highways, given the practicalities involved and the wide mix of vehicle types, driver behaviors, etc. NCHRP Report 605 should be consulted for a full discussion of why the MUTCD and AASHTO Green Book values have diverged over time. That report concluded that the AASHTO Green Book should be modified to use passing sight distance values that are the same as those in the MUTCD.

Return to Top

Retroreflectivity

Q: I noticed that Section 3A.03 in the 2009 MUTCD is reserved for future minimum levels of pavement marking retroreflectivity. What is the status of pavement marking retroreflectivity?

A: Pavement marking retroreflectivity is required but minimum levels are not currently quantified. Section 3A.02 states that markings that must be visible at night shall be retroreflective unless ambient illumination assures that the markings are adequately visible, and that all markings on Interstate highways shall be retroreflective. On April 22, 2010, the FHWA published in the Federal Register a Notice of Proposed Amendments for proposed Revision No. 1 of the 2009 MUTCD. This proposed revision would add more specific provisions for maintaining minimum retroreflectivity of longitudinal pavement markings. For more information on this proposal, see http://mutcd.fhwa.dot.gov/knowledge/proposed09mutcdrev1/index.htm. A status on the current supplemental Notice of Proposed Rulemaking is provided here.

Return to Top

Rumble Strips

Q: Are rumble strips considered traffic control devices and, if so, does the MUTCD govern their design, spacing, etc.?

A: It depends on whether the rumble strips are made of white or colored marking material or are cut into the pavement (and thus have the same color as the pavement.) A new Chapter 3J in the 2009 MUTCD addresses pavement markings that are used in conjunction with rumble strips. Transverse rumble strips can be formed by the use of strips of thermoplastic pavement marking material so they must be white if placed across the travel lanes. Rumble strips cut into the pavement as grooves and in essence the same color as the pavement are not considered pavement markings in the MUTCD. Thus, permanent rumble strips consisting of longitudinal patterns of grooves cut on the shoulder or adjacent to a centerline are not currently considered traffic control devices and are not governed by the MUTCD. Section 6F.87 contains standards, guidance, and options for temporary rumble strips used in temporary traffic control zones. That section does cover both types of rumble strips---those formed from marking material and those formed from grooves in the pavement---and describes spacing, placement, and other application information. (It should be noted that Part 6 is unique in the MUTCD in covering certain treatments that are not traffic control devices, including glare screens, attenuation devices, etc.).

Return to Top

Stop / Yield Lines

Q: Does the MUTCD allow the stop line (or yield line) to be "staggered" by lane? That is, can the stop line for the right lane be closer to the intersection than the stop line for the other lanes on an approach?

A: Staggered stop lines are specifically allowed by an Option in Section 3B.16 of the 2009 MUTCD (paragraph 16 of that section) and are illustrated in Drawing D of Figure 3B-13. This type of application of stop lines is a valuable tool used by some jurisdictions to address certain safety and operational issues, including sight distance for right turns on red after stop and visibility of pedestrians. It is a practice that is specifically mentioned in The Traffic Safety Toolbox: A Primer on Traffic Safety, a publication of the Institute of Transportation Engineers.

Return to Top

Q: Is it mandatory that a stop line be used with all STOP signs and traffic signals?

A: The 2009 MUTCD, in Section 3B.16, states the following Guidance: "stop lines should be used to indicate the point behind which vehicles are required to stop in compliance with a traffic control signal."

The 2009 MUTCD also states in Section 3B.16 that stop lines may be used to indicate the point behind which vehicles are required to stop in compliance with a Stop sign, a Stop Here For Pedestrians sign, or some other traffic control device that requires vehicles to stop. States can adopt policies or supplements to the MUTCD that are more restrictive than the national MUTCD. Most States require stop lines on all signalized approaches, and some States do make the use of a stop line mandatory with all STOP signs in their State.

Return to Top

Q: Can a stop line be used in advance of a midblock crosswalk to show vehicles where to stop for a pedestrian?

A: Yes, but only if there is a State law that requires vehicles to STOP for (rather than yield to) pedestrians in crosswalks. Section 3B.16 contains the applicable language limiting the use of stop lines to locations where a traffic control device requires vehicles to stop. A crosswalk is a traffic control device, and if State law requires road users to stop (rather than yield) if a pedestrian is in the crosswalk, a stop line for this application would be appropriate. However, if the State law requires drivers to YIELD to pedestrians in crosswalks, a Yield Line marking must be used rather than a stop line if a transverse marking is needed in advance of the crosswalk.

Return to Top

Symbols

Q: My agency wishes to use an alternative symbol for the International Symbol of Accessibility. Does the MUTCD allow this alternative symbol?

A: The International Symbol of Accessibility in the form of a pavement marking is provided in Paragraph 18 of Section 3B.20 and is illustrated in Figure 3B-22 of the MUTCD. The International Symbol of Accessibility is established through a standard by the International Organization for Standardization (ISO) in ISO 7001 to specify graphical symbols for the purposes of public information. The ISO 7001 official symbol adopts a blue colored background with a superimposed white image of a person using a wheelchair. A direct relationship between the pavement marking symbol and the ISO 7001 standard was adopted in the 2000 MUTCD.

The MUTCD does not provide for the alternative symbol. Further, the United States Department of Justice and the United States Access Board recognize the official symbol established in ISO 7001 and neither agency has adopted or endorsed the alternative symbol.

Return to Top

Return to Frequently Asked Questions.

You will need the Adobe Acrobat Reader to view the PDFs on this page.