State of The Practice for Shoulder and Center Line Rumble Strip Implementation on Non-Freeway Facilities

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Figure 1. Photo. Combination of milled CLRSs and SRSs. This figure is a photo of a two-lane roadway with milled center line rumble strips in the center and shoulder rumble strips on both sides.

Figure 2. Illustration. Profile view of milled rumble strips. This shows an illustrated profile-view comparison of sinusoidal rumble strips in comparison to milled rumble strips. The illustration is color-coded and numbered to represent the profile of each rumble strip design in relation to the State in which it is located. The California design is red and labeled number 1, and the peaks and valleys of the sine wave correspond with the peaks and valleys of the standard Minnesota milled design, which is green and labeled number 2. The Pennsylvania design is purple and labeled number 3, and the peaks and valleys of the sine wave are spaced such that they occur approximately every other peak and valley from the standard Minnesota milled design. The depth of the Pennsylvania design is the same as the Minnesota design; however, the peaks of the sine wave are below the surface of the pavement. The peaks of the California design are at the pavement surface, while the depth is slightly larger than the Minnesota and Pennsylvania designs.

Figure 3. Photo. Example profiled thermoplastic pavement marking. This figure is a photo of a two-lane roadway with profiled thermoplastic pavement markings on the center and edge lines.

Figure 4. Illustration. Overview of rumble strip dimensions. This figure is composed of three illustrations. The illustration on the right is a plan view of a two-lane roadway with shoulder rumble strips (SRSs). The illustration on the top left is a close-up view of one segment of SRSs with dimensions. In this illustration, “A” represents the offset from the pavement markings to the inside edge of the rumble strips, “B” represents the length of a strip perpendicular to the roadway, “C” represents the width of the strip parallel to the roadway, “E” represents the center-to-center spacing between strips, and “F” represents a gap or break in the rumble strips. The illustration on the bottom left (section a-a) shows a cross section of the segment of SRSs with dimensions. “C” represents the width of the strip parallel to the roadway, and “D” represents the depth of the strip.

Figure 5. Graph. Bicyclist comfort rating. This figure is a line graph comparing riders’ level of comfort ratings in relation to different rumble strip designs. The x-axis is labeled “Rumble strip type,” and the numbers 1 through 11 are displayed in order of increasing level of comfort for the different rumble strip types. The y-axis is labeled “Subjective bicyclist comfort rating,” and the numbers 1 through 5 represent the subjective bicyclist comfort rating given for each rumble strip type. Two lines are displayed on the graph. The dark blue line overlaid with triangles represents the subjective bicyclist comfort rating given for each rumble strip type while ignoring demographic information. The pink line overlaid with squares represents the subjective bicyclist comfort rating given for each rumble strip type for inclement weather riders. The rumble strips in relation to their level of comfort ratings are displayed on the horizontal axis from left to right in order from lowest to highest as 5, 4, 8, 7, 3, 9, 2, 1, 6, 10, and 11. Both lines are ascending when viewed from left to right. All measures being approximate for the blue-square line representing subjective rating values while ignoring demographics, the line graph indicates that rumble strip type number 5 displays a 1.2 rating, type 4 a 1.6, type 8 a 1.9, type 7 a 2, type 3 a 2.1, type 9 a 2.7, type 2 a 2.9, type 1 a 3.1, type 6 a 3.9, type 10 a 4.1, and type 11 a 4.5. All measures being approximate for the pink-triangle line representing subjective rating values from inclement weather riders, the line graph indicates that rumble strip type number 5 displays a 1.2 rating, type 4 a 1.6, type 8 a 1.9, type 7 a 2, type 3 a 2, type 9 a 2.6, type 2 a 2.8, type 1 a 3, type 6 a 3.8, type 10 a 4, and type 11 a 4.4.

Figure 6. Graph. Bicyclist control rating. This figure is a line graph comparing riders’ level of control ratings in relation to different rumble strip designs. The x-axis is labeled “Rumble strip type,” and the numbers 1 through 11 are displayed in order of increasing level of control for the different rumble strip types. The y-axis is labeled “Subjective bicyclist comfort rating,” and the numbers 0.5 through 5, in 0.5 increments, represent the subjective bicyclist control rating given for each rumble strip type. One line is displayed on the graph to represent the subjective control level ratings. The rumble strip types in relation to their level of control ratings are displayed from left to right on the horizontal axis in order from lowest to highest as 5, 4, 8, 7, 3, 9, 2, 1, 6, 10, and 11. This means that the line graph is ascending when viewed from left to right. All measures being approximate for the line representing subjective bicyclist control rating values, the line graph indicates that rumble strip type number 5 displays a 1.4 rating, type 4 a 1.6, type 8 a 1.9, type 7 a 2, type 3 a 2.1, type 9 a 2.7, type 2 a 2.9, type 1 a 3.2, type 6 a 3.9, type 10 a 4.2, and type 11 a 4.6.

Figure 7. Screenshot. Expert system for rural two-lane highways. This figure shows a screen capture of the interactive system for rural two-lane highways. There are six headings displaying the categories that represent governing criteria for shoulder rumble strip (SRS) installation, ranked left to right according to importance. The categories in order are Pavement Condition, Minimum Shoulder Width, Minimum Lane Width, Speed Limit, Heavy Bicyclists Traffic, Nearby Residents, and ADT. Below each category heading there are boxes with identified criteria measures that are color coded and numbered and divided into three distinct groups. Green (labeled number 1) represents criteria measures that are common practice in most agencies. Yellow (labeled number 2) represents criteria measures that are considered based on engineering judgment and requirements. Red (labeled number 3) represents criteria measures that are avoided by most agencies for SRS installation. Each box also contains a link to either a State’s guideline or policy or Wyoming Department of Transportation (WYDOT) survey results related to each criteria measure. Below the figure are symbols representing caveats to different criteria or State’s guidelines or policies. An asterisk indicates the caveat “if other requirements are met.” A superscript “a” indicates the caveat “exception for rumble stripes.” A superscript “b” indicates the caveat “centerline and shoulder/edgeline rumble strips are in combination.” A superscript “c” indicates the caveat “check the referenced link for details.” A superscript “d” indicates the caveat “clear shoulder width.” Beginning at the top left under the Pavement Condition header, there are four boxes. From top to bottom, the first two boxes representing Excellent (including a link to WYDOT survey results that equal 33 percent) and Good (including a link to WYDOT survey results that equal 79 percent) are coded green or labeled number 1. Fair (including a link to WYDOT survey results that equal 31 percent) is coded yellow or labeled number 2, and Poor, (including a link to WYDOT survey results that equal 14 percent) is coded red or labeled number 3. Under the Minimum Shoulder Width header, there are six boxes. From top to bottom, there are three boxes that are coded green or labeled number 1. The first box represents greater than or equal to 6 ft and includes links to State policies and guidelines from Alaska, Michigan (superscript b), New Hampshire, Pennsylvania, South Carolina (superscript a), Utah (superscript e), Washington, Wisconsin (superscript b), New Mexico (superscript b), and the WYDOT survey results that equal 32 percent. The second box represents 5 ft and includes links to State policies and guidelines from Maine (superscript c), Delaware, Missouri, South Carolina, and the WYDOT survey results that equal 2 percent. The third box represents 4 ft and includes links to State policies and guidelines from Arizona, Idaho, Montana, Arkansas, Minnesota, Maine (superscript c), Nevada, New Mexico (superscript c), South Carolina (superscript a), South Dakota (superscript a), and the WYDOT survey results that equal 41 percent. The next two boxes are coded yellow or labeled number 2. The first yellow box represents 3 feet (consider rumble stripes) and includes links to State policies and guidelines from South Carolina (superscript a) and Montana (superscript c). The second yellow box represents 2 ft (consider rumble stripes) and includes links to State policies and guidelines from Kentucky, South Carolina (superscript a), and Montana (superscript c). The final criteria measurement is less than 1 ft and is coded red or labeled number 3. Under the Minimum Lane Width header, there are five boxes. From top to bottom, the first two boxes are coded green or labeled number 1. The first green box represents 12 ft and includes links to State policies and guidelines from Idaho, Kentucky (superscript b), Missouri, South Dakota, Utah, Michigan (superscript b), and the WYDOT survey results equal to 44 percent. The second green box represents 11 ft and includes links to State policies and guidelines from Delaware, Kentucky (superscript b), Indiana (superscript b), Maine, Pennsylvania, Nebraska (superscript b), Virginia (superscript c), and the WYDOT survey results equal to 27 percent. The next two boxes are coded yellow or labeled number 2. The first yellow box represents 10 feet and includes links to State policies and guidelines from Arkansas, South Carolina, Kentucky (superscript b), and the WYDOT survey results equal to 27 percent. The second yellow box represents 9 ft and includes a link to the State policy or guideline from Kentucky (superscript b). The final box is coded red or labeled number 3 and displays a measure criteria of less than 10 ft. Under the Speed Limit header, there are four boxes. From top to bottom, the first two boxes are coded green or labeled number 1. The first green box represents 55 mi/h (asterisk) and includes links to State policies and guidelines from Minnesota and Pennsylvania as well as the WYDOT survey results equal to 43 percent. The second green box represents greater than or equal to 45 mi/h (asterisk) and includes links to State policies and guidelines from Arkansas, Missouri, Idaho, Kentucky, Maine, South Carolina, Utah, Virginia, Washington, and the WYDOT survey results equal to 38 percent. The next box coded yellow or labeled number 2 represents 40 mi/h speed limits and includes links to State policies and guidelines from New Hampshire and Delaware as well as the WYDOT survey results equal to 20 percent. The final box is coded red or labeled number 3 and represents roads less than 40 mi/h. Under the Heavy Bicyclist Traffic header, there is only one box, which is coded green or labeled number 1. The criteria described here are to consider bicycle friendly design. The box includes links to the NCHRP 641 report as well as State policies and guidelines from Alaska, Arizona, Delaware, Indiana, Michigan, Pennsylvania, South Dakota, Utah, and Arkansas. Under the heading for Nearby Residents there is only one box, which is coded green or labeled number 1. The criteria described here is to consider design for residential areas. There is a link to NCHRP 641 within the box, along with links to State policies or guidelines from Alaska, Idaho, Kentucky, Michigan, Missouri, New Hampshire, and Tennessee. Under the final heading for ADT, there are three boxes. From top to bottom, the first two boxes are coded green or labeled number 1. The first green box represents the criteria “no requirement” and includes a link to the WYDOT survey equal to 58 percent. The second green box represents greater than or equal to 1,000 and includes a link to Maine’s (3,000) policies and guidelines, the WYDOT survey results equal to 19 percent, and the NCHRP 641 report. The final box is coded red or labeled number 3 and represents less than 1,000 and includes a link to the WYDOT survey results equal to 24 percent.

Figure 8. Illustration. CLRS dimensions. This figure is composed of three illustrations. The illustration on the right is a plan view of a two-lane roadway with center line rumble strips (CLRSs). The illustration on the top left is a close-up view of one segment of CLRSs in the illustration on the right with dimensions. In this illustration, “A” represents the offset from the center line pavement markings to the edge of the rumble strip, “B” represents the length of a strip perpendicular to the roadway, “C” represents the width of the strip parallel to the roadway, “E” represents the center-to-center spacing between strips, and “D” represents the depth of the strip. The illustration on the bottom left shows the cross section of CLRSs. “C” represents the width of the strip parallel to the roadway, and “D” represents the depth of the strip.

Figure 9. Illustration. Bicycle roadway requirement dimensions. This illustration shows the front view of a bicyclist surrounded by corresponding dimensions that display various measurements concerning bicyclist operating space. The left side of the illustration displays horizontal measures concerning width, while the right side of the illustration displays vertical measures concerning height. Beginning at the bottom left and moving down, there are three measurements displayed below the bicyclist. The first measure is a horizontal line showing that the physical width for a bicycle is 30 inches. The next measurement is a horizontal line showing that the minimum operating width is 48 inches. The next measurement is a horizontal line showing the preferred operating distance as 60 inches. There are three measurements to the right of the illustration that represent vertical measurements concerning bicyclists. From left to right, the measurements include vertical height measurements for the bicycle handlebars, rider eye level, and vertical operating space. The line representing bicycle handlebar height displays a measurement of 44 inches. The line representing the rider eye level displays a measurement of 60 inches. The line representing the vertical operating space for a bicyclist displays a measurement of 100 inches.

Figure 10. Flowchart. Model decisionmaking framework for rumble strip installation. This illustration is a flow chart showing how to determine whether to install rumble strips and which type of rumble strips should be considered. Once the system installation criteria are established, the first step is to determine whether the study road segment meets the criteria. If the answer is no, then the agency needs to retrieve roadway data, crash data, and crash modification factors and move to the second step: determining whether it is justified by risk or crash history. If the answer is no, then the agency is recommended not to install rumble strips. “Yes” of step 2 leads to step 3a: “Is pavement condition a concern or is resurfacing imminent?” “Yes” of step 1 leads to the next step: “Does the policy address bikes, noise, and pavement quality?” If the answer is yes, then it is recommended to install standard design. If the answer is no, then move to step 3a. “Yes” of step 3a results in installing alternate treatments. “No” of step 3a leads to step 3b: “Is there a bike route or is the road used by bicycles?” “No” of step 3b leads to step 3c: “Are there multiple nearby dwellings or is noise a concern?” “No” of step 3b and step 3c results in the decision of installing standard design. “Yes” of step 3b or “yes” of step 3c leads to step 4: “Can the Rumble Strip Committee identify feasible modification?” “No” of step 4 results in the decision of installing alternate treatments. “Yes” of step 4 leads to the next step: “Are the modifications necessary?” If the answer is “yes,” then the department is recommended to install rumble strips with modification. If the answer is “no,” then the department is recommended to install standard design.