00965570

Component

https://doi.org/10.3141/1844-10

http://scholar.google.com...rand&publication_year=2003

A study of in-service traffic signs was undertaken to quantify the average effects of frost and dew on their retroreflective capabilities. The results were then compared with proposed minimum retroreflectivity standards recently developed by Federal Highway Administration (FHWA)-sponsored research for inclusion in the "Manual on Uniform Traffic Control Devices." Although the effects of frost and dew were found to be variable, average reductions in retroreflectivity levels of 79% and 60%, respectively, were found. None of the different colored signs sampled with Type I (engineering grade) sheeting was found to meet the proposed minimum levels when covered in frost or dew (with the exception of signs with white backgrounds covered in dew), even though all signs were in like-new condition. Signs sampled with Type III (high intensity) sheeting had mixed results. The findings are significant enough that they should be considered in the development of the final version of the FHWA national standards. Furthermore, those jurisdictions subject to frequent cycles of frost and dew should review usage guidelines governing the grade of sign materials used, allowing for expected loss of retroreflectivity.

This paper appears in Transportation Research Record No. 1844, Traffic Control Devices, Visibility, and Rail-Highway Grade Crossings 2003.

English

p. 79-84

2003

Transportation Research Record

0309085799

Figures (1) ; Photos (3) ; References (7) ; Tables (2)

Color; Field studies; Frost; Retroreflectivity; Sign sheeting; Standards; Traffic signs

Manual on Uniform Traffic Control Devices

Dew

Geotechnology; Highways; Materials; Operations and Traffic Management; I35: Miscellaneous Materials; I73: Traffic Control

TRIS, TRB, ATRI

Nov 18 2003 12:00AM

• DANCING DIAMONDS IN HIGHWAY WORK ZONES: EVALUATION OF ARROW-PANEL CAUTION DISPLAYS
• DETECTION AND IDENTIFICATION OF LIGHT-EMITTING DIODE TRAFFIC SIGNALS BY PROTAN OBSERVERS
• DRIVER UNDERSTANDING OF PAVEMENT MARKING COLORS AND PATTERNS
• DRIVING SIMULATORS FOR EVALUATION OF NOVEL TRAFFIC-CONTROL DEVICES: PROTECTED-PERMISSIVE LEFT-TURN SIGNAL DISPLAY ANALYSIS
• EFFECT OF VARIABLE-MESSAGE SIGNS IN REDUCING RAILROAD CROSSING IMPACTS
• FORECASTING TRAIN TRAVEL TIMES AT AT-GRADE CROSSINGS
• IMPROVING DILEMMA-ZONE PROTECTION OF ADVANCE DETECTION WITH ADVANCE-WARNING FLASHERS
• LEGIBILITY OF OVERHEAD GUIDE SIGNS WITH ENCAPSULATED VERSUS MICROPRISMATIC RETROREFLECTIVE SHEETING
• NIGHTTIME EXPERT PANEL AND PHOTOMETRIC EVALUATIONS OF UNLIGHTED OVERHEAD GUIDE SIGNS (WITH DISCUSSION AND CLOSURE)
• RELATIVE LUMINANCE OF RETROREFLECTIVE RAISED PAVEMENT MARKERS AND PAVEMENT MARKING STRIPES ON SIMULATED RURAL TWO-LANE ROADS
• SUPPLEMENTAL PAVEMENT MARKINGS FOR IMPROVING SAFETY AT RAILROAD-HIGHWAY GRADE CROSSINGS