01089575

Component

To better quantify the retroreflectance of longitudinal pavement markings throughout the state, the Florida Department of Transportation (FDOT) acquired the Mobile Retroreflectometer Unit (MRU) which has the potential benefit of fast, safe, and unbiased measurements of retroreflectivity as compared to traditional evaluation techniques such as handheld units or visual inspections. Current MRU calibration standards requires that the equipment be calibrated using a beaded line stripe that has been verified by a handheld retroreflectometer. By its very nature, this type of striping is inherently non-uniform as the beads are dispersed in a non-homogeneous pattern. This non-uniformity of retroreflectance results in issues with performing accurate, repeatable calibrations. Issues with the non-uniformity are further exacerbated by oscillations of the MRU laser light. Test results showed that the standard deviation of the retroreflectivity of the beaded line stripe was greater than 12% of the reading. In comparison, a ceramic block calibration standard had a retroreflectivity standard deviation of less than 0.5% of the rated value. Further tests showed that more repeatable calibrations and more stable readings were also achieved through use of the ceramic block. As a result, it is the view of the authors that the ceramic block is more suitable for use as an MRU calibration device.

01084478

08-2779

English

16p

2008

Transportation Research Board 87th Annual Meeting

DVD

Figures; Photos; References (4) ; Tables (3)

Calibration; Marking materials; Oscillation; Pavement management systems; Reflectorized road markings; Road markings

Mobile retroreflectometers

Florida

Design; Highways; Pavements; I22: Design of Pavements, Railways and Guideways

Transportation Research Board Annual Meeting 2008 Paper #08-2779

TRIS, TRB

Jan 29 2008 5:14PM