2013 Session: 774

• Investigation of Longitudinal Pavement Marking Retroreflectivity and Safety
  Abstract: This research was initiated to determine whether a correlation between pavement marking retroreflectivity and safety can be established. Previous research on this topic has provided mixed results and sometimes counterintuitive findings. Using data from Michigan, the researchers evaluated relationships between crashes and longitudinal pavement marking retroreflectivity. The retroreflectivity data consisted of pavement markings measurements representing white edge lines, white lane lines, yellow edge lines, and yellow center lines. The data included crashes and retroreflectivity measurements from 2002 to 2008. Only nighttime crashes that occurred at nonintersection and noninterchange segments during the nonwinter months (between April and October) were considered (wet crashes were also excluded). The following specific types of crashes were initially identified as target crashes for this study: nighttime, single vehicle nighttime, fatal plus injury nighttime, and single vehicle nighttime fatal plus injury. The findings lend support to the positive safety effects of maintaining retroreflectivity of pavement markings.
  Authors: Carlson, Paul J.; Park, Eun Sug; Kang, Dong Hun
  Authors: Carlson, Paul J.; Park, Eun Sug; Kang, Dong Hun
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management
  Session: 774
  Paper Number: 13-2512
  Practice-Ready: Yes
• Assessment of Durability of Wet Night Visible Pavement Markings: Visibility Experiment
  Abstract: This paper encompasses the visibility experiment conducted as part of a research effort to establish the durability of pavement markings in an on-road installation. Six marking technologies were installed on a portion of Route 460 in Blacksburg, Virginia. A human factors experiment in natural rain conditions was performed to establish the visibility needs of the driver. The retroreflectivity of the markings was measured at intervals of 2 to 5 months, with six measurements over the course of 23 months, though this data is discussed in a separate paper.Previous research suggested a minimum retroreflectivity of 150 mcd/m2/lx should be maintained in order to meet the visibility needs of drivers. As part of this research, a human factors experiment was conducted in order to test the validity of this recommendation. The distance at which participants could detect an end of a pavement marking was measured, as well as the retroreflectivity of the marking at those points. The relationship of detection distance and retroreflectivity found in this study suggests that as retroreflectivity increases beyond 150 mcd/m2/lx, there are diminishing returns on detection distance. This suggests that the recommended minimum is appropriate for providing increased visibility for drivers, while keeping retroreflectivity requirements at a reasonable level for marking manufacturers.
  Authors: Gibbons, Ronald B.; Williams, Brian; Cottrell, Benjamin H.
  Authors: Gibbons, Ronald B.; Williams, Brian; Cottrell, Benjamin H.
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management
  Session: 774
  Paper Number: 13-3794
  Practice-Ready: Yes
• Repeatability and Reproducibility of Mobile Retroreflectivity Units for Measurement of Pavement Markings
  Abstract: The Florida Department of Transportation (FDOT) has historically used a combination of handheld devices and visual surveys to evaluate the retroreflectivity of pavement markings. However, visual surveys have the inherent limitations of operator bias while the use of a handheld device is slow, labor intensive, and presents safety hazards. Many highway agencies have recognized that a Mobile Retroreflectivity Unit (MRU) may be a safer and a more efficient alternative to the handheld retroreflectometers. Since the measurement process relies on the operator-driven instrument, a level of uncertainty is always a concern in evaluating pavement markings with the MRU. This research is aimed at assessing the precision and bias of the MRU while using the handheld retroreflectometer as a reference device. A total of ten 1.0 mile long field sites were selected to include various pavement surface types and pavement marking materials (paints and thermoplastics). The results indicated that, when compared to the handheld retroreflectometers, the MRU demonstrated no statistical differences or bias at a 95 percent confidence level for the retroreflectivity values ranging between 200 and 800 mcd/m^2/lux. In addition, it was determined that the retroreflectivity values from two properly conducted tests using a single MRU on the same pavement marking should not differ by more than 7.8 percent and when different MRUs are used on the same pavement marking, the retroreflectivity values should not differ more than 13.3 percent. This paper presents a description of the testing program, the data collection effort, and the subsequent analyses and findings.
  Authors: Choubane, Bouzid; Sevearance, Joshua; Lee, Hyung Suk; Upshaw, Patrick B; Fletcher, James
  Authors: Choubane, Bouzid; Sevearance, Joshua; Lee, Hyung Suk; Upshaw, Patrick B; Fletcher, James
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management
  Session: 774
  Paper Number: 13-3812
  Practice-Ready: Yes
• Investigation of Longitudinal Pavement Marking Retroreflectivity and Safety
  Authors: Carlson, Paul
  Authors: Carlson, Paul
  Year: 2013
  Document Type: Presentation
  Subject: Maintenance and Preservation; Operations and Traffic Management
  Session: 774
  Paper Number: 13-2512
• Repeatability and Reproducibility of Mobile Retroreflectivity Units for Measurement of Pavement Markings
  Authors: Lee, Hyung
  Authors: Lee, Hyung
  Year: 2013
  Document Type: Presentation
  Subject: Maintenance and Preservation; Operations and Traffic Management
  Session: 774
  Paper Number: 13-3812
• Assessment of Durability of Wet Night Visible Pavement Markings: Visibility Experiment
  Authors: Gibbons, Ronald
  Authors: Gibbons, Ronald
  Year: 2013
  Document Type: Presentation
  Subject: Maintenance and Preservation; Operations and Traffic Management
  Session: 774
  Paper Number: 13-3794