The National Academies Press

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From page 208... ... 208 A P P E N D I X E In-Service RPM Retroreflectivity Measurement Introduction RPMs become less effective for two main reasons; the devices can either be dislodged from the roadway or they lose their retroreflective ability. Both circumstances are mainly caused from vehicular and environmental wear over time. Read the entire page →
From page 209... ... In-Service RPM Retroreflectivity Measurement 209 RPMs. Unfortunately, it is not a realistic option for evaluating a large quantity of RPMs because the device must be lifted and brought to each individual RPM that needs to be evaluated. Read the entire page →
From page 210... ... 210 Performance Criteria for Retroreflective Pavement Markers Closed-Course Test Area The closed testing was conducted at the Texas A&M University RELLIS Campus. Sections of the facility are marked with stripes and RPMs. Read the entire page →
From page 211... ... In-Service RPM Retroreflectivity Measurement 211 (a) Read the entire page →
From page 212... ... 212 Performance Criteria for Retroreflective Pavement Markers RPMs at the closed-course test area, the county-maintained road test area, and the wet testing in the TTI visibility lab. Before each set of measurements, the retroreflectometer was calibrated according to the manufacturer specifications. Read the entire page →
From page 213... ... In-Service RPM Retroreflectivity Measurement 213 values in the standard file were generally all from the pavement markings that were measured at the same time as the RPMs. Figure E-3 provides an image of the mobile retroreflectometer mounted to a vehicle. Read the entire page →
From page 214... ... 214 Performance Criteria for Retroreflective Pavement Markers Figure E-3. Mobile retroreflectometer mounted on vehicle. Read the entire page →
From page 215... ... In-Service RPM Retroreflectivity Measurement 215 Portable Retroreflectometer Data The portable retroreflectometer was used on three test areas of 24 RPMs at the closedcourse test area. The retroreflectivity values at the closed-course test area ranged from 19 mcd/lux to 570 mcd/lux. Read the entire page →
From page 216... ... 216 Performance Criteria for Retroreflective Pavement Markers RPM, hits less than 1,000 mcd/m2/lux would be ignored because the laser more than likely only hit a portion of the RPM. The rest of the multiple hits then had their RL values averaged. Read the entire page →
From page 217... ... In-Service RPM Retroreflectivity Measurement 217 mW, the results were much different. Only two trials at 70 mph were done because speed was found to not impact the detection capabilities. Read the entire page →
From page 218... ... 218 Performance Criteria for Retroreflective Pavement Markers (a) Read the entire page →
From page 219... ... In-Service RPM Retroreflectivity Measurement 219 (a) Read the entire page →
From page 220... ... 220 Performance Criteria for Retroreflective Pavement Markers (a) Read the entire page →
From page 221... ... In-Service RPM Retroreflectivity Measurement 221 Overall, it does not appear that the two devices produce values that can be used to predict one another. The mobile device does have the ability to monitor RPM presence, but the visibility information the system provides does not appear to be useful. Read the entire page →
From page 222... ... 222 Performance Criteria for Retroreflective Pavement Markers (a) Read the entire page →
From page 223... ... In-Service RPM Retroreflectivity Measurement 223 Findings and Recommendations The mobile retroreflectometer has the ability to record RL values for RPMs while traveling at highway speeds, while simultaneously evaluating the pavement markings on the roadway. The research found that the mobile retroreflectivity values for the RPMs do not correlate well with the portable RPM retroreflectometer. Read the entire page →
From page 224... ... 224 Performance Criteria for Retroreflective Pavement Markers 6. Migletz, J., J Read the entire page →

From page 208...

... 208 A P P E N D I X E In-Service RPM Retroreflectivity Measurement Introduction RPMs become less effective for two main reasons; the devices can either be dislodged from the roadway or they lose their retroreflective ability. Both circumstances are mainly caused from vehicular and environmental wear over time.