摘要(英) |
LEDs have been widely used in lighting applications, including traffic signs and traffic signals. Yet the design of LED traffic signs has no universal specifications. This study evaluates four custom-made LED highway traffic signs with different designs, including external LED lighting, LED backlight, regional LED backlight and LED lightbox. Participant observation studies were performed to investigate which design would have the best visual quality.
The ergonomic experiments use the four LED traffic signs as the experimental factor. The signage dimension is one-sixth of the real traffic signs, and the observation distance is 25 m. The luminance range of internal lighting signs is set at 200-350 nit, which complies with the “Technical Regulations of LED Road Traffic Signs” published by the Bureau of Energy, Ministry of Economic Affairs. The illuminance on the non-self-luminous sign with external LED lighting is set to 400 lux, within the range regulated by the “Road Traffic Construction Regulations” enacted by the Ministry of Transportation and Communications. We collected subjective scores from the participants, including the legibility, visual comfort, preferences and ranking.
The subjective scores were analyzed by the statistical software. The results showed that self-luminous traffic signs provide superior legibility, visual comfort, preferences and ranking than the non-self-luminous one. We also found the ambient illumination a key factor affecting the visual quality. Among the traffic signs self-luminous with LEDs, regional LED backlight is most susceptible to the ambient illumination because the green background is not lit. The green background relies on the ambient illumination to project on the retroreflective sheet to provide brightness. A small variation in the ambient illumination would result in tremendous change to the visual performance of regional LED backlight. Both LED lightbox and LED backlight light up the whole signage area and provide similar visual sensations to the participants, with the subjective scores of LED lightbox significantly better than that of LED backlight. Based on the four LED traffic signs designed and evaluated in this study, we suggest to use LED lightbox for future installations of LED traffic signs. |
參考文獻 |
[1]記者鄭瑋奇,增加80米夜視距離 內照式LED標誌續試辦,自由時報, 民國104年12月6日。
[2]中華民國交通部,交通工程規範,中華民國,民國104年1月9日。
[3]R.E. Dewar, J. G. Ells, and G. Mundy, “Reaction time as an index of traffic sign perception,” The Journal of the Human Factors and Ergonomics Society 18, pp.381-391, 1976.
[4]G.M. Long and D. F. Kearns, “Visibility of text and icon highway signs under dynamic viewing conditions,” The Journal of the Human Factors and Ergonomics Society 38, pp.690-701, 1996.
[5]J. D. Bullough, P. R. Boyce, A. Bierman, K. M. Conway, K. Huang, C. P. O′Rourke, C. M. Hunter, A. Nakata, “Response to simulated traffic signals using light-emitting diode and incandescent sources,” Transportation Research Record 1724, pp. 39-46, 2000.
[6]H. J. Schmidt-Clausen, J. Th. H. Bindels,“Assessment of discomfort glare in motor vehicle lighting,” Lighting Research and Technology 6, pp.79-88, 1974.
[7]E. Hartmann, “Driver visual requirements”, Proceedings of the International Automobile Safety Conference, New York, 1970.
[8]M. A. Recarte, L.M.Nunes, “Mental workload while driving: Effects on visual search, Discrimination, and decision making” Journal of Experimental Psychology, Vol 9, No2, pp.119-137, 2003.
[9]J.L. Harbluk, Y. I. Noy, “The impact of cognitive distraction on visual behaviour and vehicle control” (Report no. TP13889E) (Report). Ontario: Transport Canada, 2002.
[10]中華民國經濟部能源局,LED道路交通標誌牌技術規範,中華民國,民國102年8月9日。
[11]FHWA, Manual on Uniform Traffic Control Devices, USA, 2009.
[12]中華民國交通部國道高速公路局,交通工程標準圖,中華民國,民國93年2月11日。
[13]國道新建工程局,國道公路照明設計準則,中華民國,民國80年1月1日。
[14]Illuminating Engineering Society of North America(IESNA), Roadway Sign Lighting, Recommended Practice RP-19-01, New York, 2001
[15]林清山,心理與教育統計學,東華書局,台北,312-313頁,1992。
[16]洪蘭、曾志朗,心理學實驗研究法,遠流出版公司,台北,86-113頁,1989。
[17]朱經明,教育及心理統計學,武南圖書,台北,234-244頁,2007。
[18]J. J. Shaughnessy, E. B. Zechmeister and J. S. Zechmeister,Research Methods in Psychology, 8th ed., McGraw-Hill, New York, pp.245-259, 2008.
[19]J. D. Bullough, J. A. Brons, R. Qi, and M. S. Rea,“Predicting discomfort glare from outdoor lighting installations.” Lighting Research and Technology, vol. 40, no.3, pp.225-242, 2008.
[20]De Boer J. B. “Visual perception in road traffic and the field of vision of the motorist,” in Public Lighting, J. B. De Boer ed., Eindhoven, Netherlands, Philips Technical Library, pp.11-96, 1967.
[21]A Field, Discovering Statistics Using SPSS., Sage publications Press.,
London, 2009.
[22]林孟緯,「LED廣告看板的閃爍眩光與視覺舒適度評估」,國立中央大學,碩士論文,民國103年。
[23]范成儀,「LED交通標誌之最適輝度與對比度研究」,國立中央大學,碩士論文,民國104年。
[24]中興工程顧問股份有限公司,「國道照明應用 LED 路燈可行性評估」,中華民國交通部國道高速公路局,民國101年11月13日。
[25]陳勇翔,「在不同環境照度下LED 顯示標誌視覺人因之研究」,大同大學,碩士論文,民國99年。
[26] 國立中央大學光電中心,「國道LED標誌規範及功能規格之研究」,中華民國交通部國道高速公路局,民國104年8月。 |