Repeatability of Mobile Retroreflectometer Unit for Measurement of Pavement Markings

• Published in: Transportation research record Vol. 2169; no. 1; pp. 95 - 106
• Main Authors: Holzschuher, Charles, Choubane, Bouzid, Fletcher, James, Sevearance, Joshua, Lee, Hyung Suk
• Format: Journal Article
• Language: English
• Published: Los Angeles, CA SAGE Publications 01.01.2010
• DOI: 10.3141/2169-11
• ISSN: 0361-1981

The mobile retroreflectometer unit (MRU) has been recognized by highway agencies as an appealing alternative to handheld retroreflectometers because of its improved safety and efficiency. Over the past 4 years, the Florida Department of Transportation has been researching the use of the MRU for evaluating pavement markings continuously and reliably at traffic speeds. Because the stripe surface is nonuniform and the measurement process relies on the operator-driven instrument device, there is some uncertainty in evaluating pavement markings with the MRU. As part of the broader effort for MRU implementation, this research assesses MRU precision in repeatability for pavement marking retroreflectivity. Six designated sections of roadway were selected at random for testing on various pavement surfaces and pavement stripes (paint and thermoplastic). Retroreflectivity data were collected only on the white edge lines of the test sites. The survey limits were selected so that the effect of nonretroreflective-related variables, such as breaks in the pavement markings, inclines, declines, and curves in the roadway, could be minimized. The data were analyzed to determine the pavement marking characteristics at each test location for retroreflectivity at 80 km/h (50 mph) using the reduced 30-m geometry standard. Results indicated that the retroreflectance values from two properly conducted tests using the same MRU on the same pavement marking should not differ by more than 20.1 mcd/m2/lux or 6.7% at a 95% confidence level for retroreflectivity values ranging between 200 and 450 mcd/m2/lux. This paper presents a description of the testing program, the data collection effort, and the subsequent analyses and findings.