The National Academies Press

Currently Skimming:

Pages 33-54

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.

From page 33... ... 33 Survey and Review of State Practices The research team sent surveys to representatives of all 50 states to identify the current state of use of RPMs. The survey was administered in two phases. Read the entire page →
From page 34... ... 34 Performance Criteria for Retroreflective Pavement Markers Figure 2. Questionnaire for initial survey conducted in 2015. Read the entire page →
From page 35... ... Survey and Review of State Practices 35 Figure 4. Group 2 questionnaire for follow-up survey conducted in 2018. Read the entire page →
From page 36... ... 36 Performance Criteria for Retroreflective Pavement Markers 3.1 Use of RPMs Information regarding the use of RPMs was collected using both the state survey and the review of state policies regarding RPMs. Table 9 and Table 10 provide the survey responses from both the initial and follow-up surveys conducted in 2015 and 2018 and a summary of RPM usage for all 50 states. Read the entire page →
From page 37... ... Survey and Review of State Practices 37 • Idaho and Oklahoma reported not using RPMs in the surveys; however, their state documentation indicates the use of RPMs. (Oklahoma responded in the survey to using RPMs in the past and mentioned that the existing RPMs are being removed with a very low priority.) Read the entire page →
From page 38... ... 38 Performance Criteria for Retroreflective Pavement Markers The following sections focus on summarizing data from only the 35 states (plus Washington, DC, and Puerto Rico) with either the survey responses or state documentation indicating the current use of RPMs. Read the entire page →
From page 39... ... Survey and Review of State Practices 39 Some inconsistencies can be observed between the survey responses (Table 13) and the state policies (Table 14) Read the entire page →
From page 40... ... 40 Performance Criteria for Retroreflective Pavement Markers As Table 15 indicates, there is no uniformity in costs of RPMs among the eight states that responded. The cost of an RPM ranges from approximately $2.50 to $70.00 per marker. Read the entire page →
From page 41... ... Survey and Review of State Practices 41 States Condition Alabama RPMs are used system-wide on all interstate, federal, and state routes. Some counties and cities also use RPMs, but it is not widespread. Read the entire page →
From page 42... ... 42 Performance Criteria for Retroreflective Pavement Markers States Condition Arizona • Type E (edge line) pavement markers should not be installed in areas of continuous illumination or where mechanical sweeping is routinely performed.68 • Pavement markers can be installed in the rumble strip if necessary.68,70 • Raised RPMs at elevations < 4,000 ft, recessed RPMs > 4,000 ft.54,55,56,58,59,60 Delaware • Always: interstates, freeways, expressways, and principal arterials. Read the entire page →
From page 43... ... Survey and Review of State Practices 43 Category States All DOT-maintained roads (minimal exclusions) NJ, OH, TX All roads in a state-specific system KY, OR All freeways, highways, expressways, and similar DE, MA, MI, PA, VA Illumination (presence of roadway lighting) Read the entire page →
From page 44... ... 44 Performance Criteria for Retroreflective Pavement Markers Center-toCenter Distance Quantity States, DC, and PR 80 ft 18 AK38; AL51; DE83; IL96; IN99; KY102,103,104,105,106,107,108,109,110,111; MA123; MD119; NC142; NJ41; OH (120 ft on freeways) 146; PA153; SC156; TN159; TX163; VA168,169; WA173,175; WV180 40 ft 10 AR73; AZ68; FL87; GA89,90; LA (4x in a row spaced 2 ft apart on centerline for urban interstates) Read the entire page →
From page 45... ... Survey and Review of State Practices 45 Table 22 shows that, with a total of nine states, the most common spacing along yellow doublesolid centerlines on curves is 40 ft. Except for Florida,87 all states having a guideline for closer RPM spacing on curves have an original tangent spacing guideline of 80 ft or longer. Read the entire page →
From page 46... ... 46 Performance Criteria for Retroreflective Pavement Markers Center-to-Center Distance Quantity States, DC, and PR 80 ft 15 AK38; AL51; AR72; IL96; IN99; KY106; NC142; NJ41; OH146; PA153; SC156; TN159; TX163; VA169; WA163 40 ft 9 AZ67; FL87; GA89; LA114; MS131; NM136; NV134; OR (80 ft optional) Read the entire page →
From page 47... ... Survey and Review of State Practices 47 As Table 25 shows, a weak plurality of states have a spacing guideline of 20 ft, and there is no semblance of a consensus on the spacing guidelines for RPMs in gore areas. Each state that has a guideline for RPM spacing in gore areas has a guideline that is lesser in value than the state's guideline for white broken lane line spacing. Read the entire page →
From page 48... ... 48 Performance Criteria for Retroreflective Pavement Markers As Table 27 illustrates, a majority of states recommend a single marker centered between the two stripes for each RPM placement. Three of these states specify an exception for multilane roads; two states (South Carolina and Texas) Read the entire page →
From page 49... ... Survey and Review of State Practices 49 As Table 28 indicates, a majority of states expressly recommend using red RPMs to delineate wrong-way traffic flow. Maryland specifies in its state MUTCD that red markers can also delineate truck escape ramps.119 New York specifies in its MUTCD supplement that red RPMs can be used to delineate symbols and transverse lines in addition to wrong-way traffic flow.138 However, no other documentation concerning these alternate implementations was found. Read the entire page →
From page 50... ... 50 Performance Criteria for Retroreflective Pavement Markers Attribute Quantity States, DC, and PR 1.8 (ASTM D4280 and ASTM D4383) 185,186 15 AK39; AR74; AZ71; DE85; FL88; GA92; IL97; IN100; LA114,115,116,117,118; NC144; NY139,140; OK151; SC157; VA170; WV182 2.0 1 TX (snowplowable RPMs: 2.0 at 4° entrance angle) Read the entire page →
From page 51... ... Survey and Review of State Practices 51 Guidelines giving reflectivity values in mcd/lux were converted to cd/fc using the following equation, with the result rounded to the nearest tenth: cd fc cd fc mcd lux 1 1000 mcd 10.76391 lux 1 [2] = × × Per ASTM D4280 and ASTM D4383, mcd/lux is the SI and accepted worldwide unit norm.185,186 However, the vast majority of states list these values in the inch-pound units of cd/fc, so it is in cd/fc that they are listed here. Read the entire page →
From page 52... ... 52 Performance Criteria for Retroreflective Pavement Markers As Table 36 shows, a major issue that states using snowplowable RPMs face is the snowplowable casing dislodging from the roadways. Three states (Arizona, Arkansas, and Kentucky) Read the entire page →
From page 53... ... Survey and Review of State Practices 53 Table 37. RPM replacement criteria based on survey responses. Read the entire page →
From page 54... ... 54 Performance Criteria for Retroreflective Pavement Markers • Most states space RPMs at 40 ft or 80 ft (80 ft is most common) when supplementing centerline or broken lane line markings. Read the entire page →

From page 33...

... 33 Survey and Review of State Practices The research team sent surveys to representatives of all 50 states to identify the current state of use of RPMs. The survey was administered in two phases.