01594456

Component

The existence of dirt on traffic sign faces has effects on both sign visibility and legibility. However, among damaged signs, dirty traffic signs are unique since their damage is not permanent and they just can be cleaned instead of replaced. This research aimed to identify the most important contributing factors to traffic sign dirt. To do this, more than 97,000 traffic signs in Utah were measured by deploying an instrumented vehicle. Each individual daytime digital image was inspected for dirt. Location and climate observations obtained from online sources were compiled using ArcGIS throughout the process. The Chi-square test was employed to identify contributing factors to traffic sign dirt. Finally, random forests statistical model was utilized to analyze the data and rank all of the factors based on their importance to the sign dirt. After analyzing the data, it can be concluded that ground elevation, sign mount height, and air pollution had the highest effect on making traffic signs dirty. The findings of this investigation may assist transportation agencies in determining traffic signs with a higher likelihood of sign dirt. In this way, agencies might schedule to clean such traffic signs more frequently.

This paper was sponsored by TRB committee AHD55 Standing Committee on Signing and Marking Materials.

01584066

16-3785

English

13p

2016

Transportation Research Board 95th Annual Meeting

Digital/other

Figures; Maps; Photos; References; Tables

Air pollution; Chi square test; Cleaning; Deterioration by environmental action; Height; Legibility; Traffic signs; Visibility

Dirt; Elevation; Visual obstructions

Utah

Environment; Highways; Maintenance and Preservation; Operations and Traffic Management; Safety and Human Factors

Transportation Research Board Annual Meeting 2016 Paper #16-3785

PRP, TRIS, TRB, ATRI

Jan 12 2016 5:39PM