01081177

Component

In an effort to obtain field luminance values provided by different sign sheeting materials, a set of white retroreflective traffic sign sheetings from various ASTM D4956 sheeting types and a newer micro full-cube microsprismatic sheeting were obtained, and white and green blank signs were constructed for each sheeting type. Blank white signs were positioned in typical right and left shoulder positions, and green signs were positioned in typical overhead mounted positions in the field. Field measurements of luminance were conducted using a CCD photometer for each mounting position for each material from inside a 2006 model year Chevrolet Trailblazer sports utility vehicle at varying distances to the signs. In general, the micro full-cube retroreflective sheeting provided the highest luminances, whereas the beaded Type III sheeting provided the lowest luminances in all sign locations. The observed luminances were below the optimal luminance levels suggested in relevant human factors literature, suggesting further room for improvement. In a parallel effort, smaller samples were cut out from the same rolls of sheeting as the signs. These samples were characterized in their retroreflective properties using a CCD-based retroreflectometer in the laboratory. These retroreflectivity data matrices were then incorporated into a computer model known as the Tarvip model, and scenarios were generated to simulate the field condition using the Tarvip model. Luminances obtained in the field are compared to the luminances calculated with the Tarvip model. In Tarvip, a median US headlamp beam pattern was used. Results show systematic differences between field luminances and model-provided luminances especially at long and short distances in absolute terms, where field luminances were generally lower than the luminances suggested by Tarvip. However, in relative ranking of materials, the model findings notably agree with the field data. The agreement in relative ranking suggests that models such as Tarvip can be used reliably in determining relative performance of sheetings, but more headlamp data are needed to determine the general distribution of actual field luminances.

01081138

English

26p

2007-4

18th Biennial TRB Visibility Symposium

CD-ROM

Figures (11) ; References (34) ; Tables (3)

Analysis; Distance; Field tests; Luminance; Mathematical models; Retroreflectivity; Roads; Sign sheeting; Simulation

Design; Highways; Planning and Forecasting; I21: Planning of Transport Infrastructure

TRIS, TRB, ATRI

Nov 22 2007 5:18PM

• A Review of Disability and Discomfort Glare Research and Future Direction
• Challenges to Implementation of Work Zone Lighting Guidelines
• Comparing Data Collection Scenarios Used for Examining Drivers' Sign Viewing Behavior: Closed Course Versus Open Road Environments
• Development of the Human Factors Guidelines (HFG) for Road Systems
• Driver Understanding of the Purpose of Red Retroreflective Raised Pavement Markings
• Driver-Focused Design of Retroreflective Sheeting for Traffic Signs
• Effect of Outdoor Lighting on Perception and Appreciation of End-Users
• Evaluation of Road-Sign Geometry Parameter Space
• Fluorescent Orange Retroreflective Raised Pavement Marker Color Recognition Study
• I-95 Corridor Mile Marker and Ramp Designation Signing
• Modern Pavement Marking Systems: The Relationship Between Optics and Nighttime Visibility
• Pavement Marking Visibility: Brighter Versus Wider
• Performance Assessment of Vehicle Headlamps
• Recommendations for Minimum Pavement Marking Retroreflectivity Values Based on Tarvip Analyses
• Revealing Power and Road Lighting Design
• The Relationship of Vertical Illuminance to Pedestrian Visibility in Crosswalk