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Title:

Investigation of the Light Emitting Diode Traffic Signs Visual Performance Under Low Visibility Condition

Accession Number:

01663064

Record Type:

Component

Abstract:

Light emitting diode (LED) traffic sign is a novel type of traffic sign which has been applied on expressway recently. The lack of design criteria for LED traffic sign has caused many problems, e.g. the reasonable luminance interval is undefined. This paper explores the visual performance for LED traffic signs under low visibility condition compared with the conventional retroreflectivity traffic signs (CRTS). 30 drivers are recruited to participate in both the static field recognition experiment and the dynamic field driving experiment. CRTS and LED traffic signs in two lighting forms, namely the lattice LED traffic signs (LLED) and semi-permeable panel display LED traffic signs (SPLED), are tested. The static field experiment results show that the two characteristics of SPLED-text height (TH) and stroke width (SW) have no significant effect on determination of the optimal luminance. The optimal luminance of SPLED installed 5m high in expressway with 60cm TH and 1/10cm SW/TH range from 120cd/m² to 140cd/m² at nighttime is proper. The dynamic field driving experiment under the inclement weather environment (torrential rain of 200mm/24h) found that LED traffic signs have better visual performance than CRTS. The 85th percentiles for visual recognition distances under low visibility condition of CRTS, LLED, and SPLED are 63.0m, 77.7m and 94.2m, respectively. The findings of this study will provide rationale for urban expressway administration in LED active light-emitting road traffic signs design.

Supplemental Notes:

This paper was sponsored by TRB committee AHD55 Standing Committee on Signing and Marking Materials. Alternate title: Visual Performance of Light-Emitting Diode Traffic Signs Under Low-Visibility Condition.

Report/Paper Numbers:

18-06077

Language:

English

Authors:

Wei, Zhonghua
Liu, Sheng
Wang, Shaofan
Qiu, Shi
Liang, Jingxuan

Pagination:

6p

Publication Date:

2018

Conference:

Transportation Research Board 97th Annual Meeting

Location: Washington DC, United States
Date: 2018-1-7 to 2018-1-11
Sponsors: Transportation Research Board

Media Type:

Digital/other

Features:

Figures; References

Subject Areas:

Highways; Operations and Traffic Management

Source Data:

Transportation Research Board Annual Meeting 2018 Paper #18-06077

Files:

TRIS, TRB, ATRI

Created Date:

Jan 8 2018 11:34AM