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Frequently Asked Questions - Part 3 - Markings

The following list of questions relates to the MUTCD Part 3 - Markings:

  1. 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?
  2. I am interested in the historical aspects of pavement markings. For example, when did yellow start being used as the color of a left edge line on a one-way roadway or ramp?
  3. 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?
  4. Why can't a single solid yellow center line be used on a city street or narrow roadway?
  5. Is it illegal to cross a double yellow centerline on a road when making a left turn into a private driveway?
  6. Why do the MUTCD and the AASHTO Green Book have different values for passing sight distance?
  7. Does a solid white lane line prohibit crossing to change lanes on the approach to an intersection?
  8. How far in advance of a lane drop should the special lane drop markings begin?
  9. Why are dotted lane lines now required instead of broken lane lines to separate an acceleration lane or deceleration lane from the adjacent through lane?
  10. Why wasn't Section 3B.09 changed to also require 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?
  11. 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?
  12. 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?
  13. 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?
  14. Is it mandatory that a stop line be used with all STOP signs and traffic signals?
  15. Can a stop line be used in advance of a midblock crosswalk to show vehicles where to stop for a pedestrian?
  16. What are the warrants for installing a marked crosswalk at a midblock location?
  17. On a roadway alongside a building within a local shopping mall, there is a crosswalk with one end at a sidewalk adjacent to a store entrance and the other end at a parking area driving aisle that runs perpendicular to the building frontage. Does the MUTCD allow a crosswalk to terminate at a driving aisle of a parking area, or must the crosswalk terminate at a curb?
  18. I have seen yellow curbs to the right of traffic, contrary to the general principles of yellow and white markings. Does this yellow curb mean no parking?
  19. Figure 3C-3 seems to illustrate a single-lane roundabout with different geometric treatments on each approach leg, something that probably would never be built. Why was this figure included in the MUTCD?
  20. 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?
  21. Are "detectable warnings" (truncated domes) required for all curb ramps and, if so, what are the design requirements?
  22. Are rumble strips considered traffic control devices and, if so, does the MUTCD govern their design, spacing, etc.?

Part 3 - Markings: Frequently Asked Questions

  1. 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. The deadline for comments on the proposal to be submitted to the rulemaking docket is August 20, 2010. For more information on this proposal, see http://mutcd.fhwa.dot.gov/knowledge/proposed09mutcdrev1/index.htm.

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  1. Q: I am interested in the historical aspects of pavement markings. For example, when did yellow start being used as the color of a left edge line on a one-way roadway or ramp?

A: The 1971 edition was the first time a yellow left edge line appeared in the MUTCD. A yellow left edge line was recommended (Guidance) "on divided highways where medians are extremely narrow or where obstructions exist to restrict the area beyond the edge line from use as an emergency refuge." In the 1978 edition, the use of the color yellow for all left edge lines became mandatory. For more information on this and other questions involving the history of pavement markings, the 2000 report entitled "Evolution of the U.S. Pavement Marking System" by Dr. H. Gene Hawkins is an excellent reference. The report may be viewed and downloaded at: https://ceprofs.civil.tamu.edu/ghawkins/MUTCD-History_files/MarkingColorEvolution.pdf.

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  1. 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. There does not appear to be any research evaluating relative effectiveness of these different practices. Anecdotally, they all seem to be effective in making the white or yellow lines stand out more on a light colored pavement.

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  1. Q: Why can't a single solid yellow center line be used on a city street or narrow roadway?

A: Section 3B.01 prohibits the use of this marking on a two-way roadway. Even though this specific language was first added to the MUTCD with the 2009 edition, a single solid yellow center line has never been allowed since the 1971 edition of the MUTCD. The reason is that there is no defined meaning of such a line in terms of whether passing is allowed or prohibited in one or both directions. Also, the two-line system for center line markings is well established and clearly understood by road users. Using a single yellow center line would only save 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.

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  1. 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.

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  1. 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 different values have existed. 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.

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  1. Q: Does a solid white lane line prohibit crossing to change lanes on the approach to an intersection?

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 obviously 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".

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  1. Q: How far in advance of a lane drop should the special lane drop markings begin?

A: For a lane drop on a freeway or expressway, Section 3B.04 and Figure 3B-10 both note that a lane drop marking consisting of a wide, white dotted line, 3 feet in length with a 9 feet gap separation, shall be used and that it should begin at least ½ mile in advance of the theoretical gore of the freeway exit ramp. For lane drops on conventional roads, where a through lane becomes a "trap lane" (that is, a turn only lane), Section 3B.04 states that a lane drop marking consisting of a wide, white dotted line, 3 feet in length with a 9 feet gap separation shall also be used and should begin a distance in advance of the intersection that is determined by engineering judgment as suitable to enable drivers who do not desire to make the mandatory turn to move out of the lane being dropped prior to reaching the queue of vehicles that are waiting to make the turn. The lane drop marking should begin no closer to the intersection than the most upstream regulatory or warning sign associated with the lane drop. Section 3B.04 also requires the use of a wide, white dotted lane line for auxiliary lanes of 2 miles or less between interchanges and for auxiliary lanes between intersections of 1 mile or less (see Figure 3B-10.) It is also important to note that where the number of through travel lanes is reduced between interchanges or intersections, that is not a "lane drop" but rather that is considered a "lane reduction transition", the markings for which are prescribed in Section 3B.09 and Figure 3B-14.

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  1. Q: Why are dotted lane lines now required instead of broken lane lines to separate an acceleration lane or deceleration lane from the adjacent through lane?

A: The previous use of normal broken lane lines did not provide sufficient information to indicate to road users that the acceleration lane or deceleration lane is not a lane that continues beyond the interchange. The dotted lane line markings now required in Section 3B.04 of the 2009 MUTCD clearly distinguish these as lanes that do not continue.

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  1. Q: Why wasn't Section 3B.09 changed to also require 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. Human factors studies need to be done to evaluate driver understanding of and behavior in reaction to both types of marking patterns. If and when such experimentation and studies are done, depending on the results, FHWA may consider proposing changes in Section 3B.09 and Figure 3B-14 in the future.

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  1. 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 Section 1A.10 provisions. 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.

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  1. 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.

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  1. 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 Figure 3B-13, drawing D. 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 publication of the Institute of Transportation Engineers.

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  1. 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." As Guidance, this is a recommended but not mandatory condition. 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.

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  1. 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.

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  1. 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://drusilla.hsrc.unc.edu/cms/downloads/Effects_Un_MarkedCrosswalks_Summary.pdf.

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  1. Q: On a roadway alongside a building within a local shopping mall, there is a crosswalk with one end at a sidewalk adjacent to a store entrance and the other end at a parking area driving aisle that runs perpendicular to the building frontage. Does the MUTCD allow a crosswalk to terminate at a driving aisle of a parking area, or must the crosswalk terminate at a curb?

A: The MUTCD does not prescribe that a crosswalk must terminate at curbs on both sides of a roadway. A jurisdiction or private property owner may determine that the appropriate place for one end of a crosswalk is a driving aisle that intersects a roadway. No matter where the crosswalk terminates, it must meet the provisions of Section 3B.18.

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  1. Q: I have seen yellow curbs to the right of traffic, contrary to the general principles of yellow and white markings. Does this yellow curb mean no parking?

A: Curb markings are discussed in Section 3B.23 and the marking of islands is discussed in Chapter 3I. For delineation and visibility purposes, retroreflective solid yellow markings are recommended for use on the nose of raised medians and island curbs in the line of traffic flow where all traffic must pass to the right. Since yellow and white curbs are frequently used for island curb delineation and visibility, it is advisable to establish parking regulations through the installation of standard signs discussed in Sections 2B.46 through 2B.48 rather than via colored curbs. However, Section 3B.23 does allow local highway agencies to prescribe special colors for curb markings to supplement standard signs for parking regulations. In those cases where curb markings are used without signs to convey parking regulations, Section 3B.23 recommends that a legible word marking regarding the regulation (such as "No Parking") should be placed on the curb.

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  1. Q: Figure 3C-3 seems to illustrate a single-lane roundabout with different geometric treatments on each approach leg, something that probably would never be built. Why was this figure included in the MUTCD?

A: It's important to remember that the MUTCD is not the Roundabouts Design Guide. The two documents serve different purposes. The MUTCD has the force of law and it only regulates the design and application of signs, markings, signals, and other traffic control devices. It does not regulate, provide guidance for, or even attempt to illustrate proper geometric design. Figure 3C-3 is only intended to show the markings applicable to single lane roundabouts (which can have various geometries), not to show the recommended geometry or physical construction details of the roundabout, its central island, splitter islands, etc. Also, Figure 3C-3 is a "composite" drawing, showing two approach legs with raised splitter islands, one approach leg with a mountable splitter island, and one approach leg with flush painted splitter island. It's unlikely that any one roundabout would be built with this "mix" of geometrics, but again, this is not the Roundabouts Design Guide, and this is not intended to suggest that a roundabout be designed this way. It's just showing the appropriate pavement markings for each of those 3 types of approach geometrics.

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  1. 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 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 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 used for pavement marking lines. Also, retroreflective colored pavements of any color or pattern are prohibited between crosswalk lines.

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  1. Q: Are "detectable warnings" (truncated domes) required for all curb ramps and, if so, what are the design requirements?

A: Currently, detectable warnings are not included in the MUTCD as a traffic control device. However, they are a requirement stemming from the Americans with Disabilities Act (ADA), to warn visually-disabled (blind or low-vision) pedestrians of the change from sidewalk to roadway as they leave the ramp to enter the crosswalk. On July 30, 2004, FHWA issued a memorandum reiterating that agencies must continue to comply with current ADA standards -- including those for detectable warnings at curb ramps and blended transitions -- when building new and altering existing pedestrian facilities. Further, the U.S. Access Board, the agency that administers the ADA, is planning to initiate a rulemaking process for adopting ADA Accessibility Guidelines for the Public Right-of-Way. The latest information on current and proposed design and placement requirements for detectable warnings may be viewed on the Access Board's Web site at http://www.access-board.gov/guidelines-and-standards/streets-sidewalks/public-rights-of-way/guidance-and-research/detectable-warnings-update. The current guidance does not specify a particular color but requires the detectable warning to be a color that contrasts with the sidewalk---light on dark or dark on light.

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  1. 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.).

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