Field test on visibility at cycle crossings at night.

Nygårdhs, S. Fors, C. Eriksson, L. & Nilsson, L.

This report describes a field study which is part of the project “Road user support in night-time traffic”. The first steps in the project were a literature review on night-time traffic in urban areas and a focus group study where road users’ needs and experiences of night-time traffic in urban areas were discussed. The aim of the field study was to compare the night-time visibility distance of cycle crossings to the night-time visibility distance of bicyclists at the corresponding cycle crossings. This was tested both for dry and wet road surface. Twelve volunteers participated in the study; six at dry road surface and six at wet road surface conditions. They sat as passengers in an instrumented car at night travelling along a test route including a total of 19 cycle crossings. The participants indicated when they noticed bicyclists (stationary dummies) and cycle crossings along the test route, and the visibility distance was registered and stored. Physical parameters measured in the field study were illuminance, daylight luminance coefficient and retroreflectivity. From these measures the contrast between the road surface and marking was calculated, as well as the difference between the illumination at the front and at the back of the bicyclist dummy. The main result of the study was that the bicyclist dummy was always seen at longer distances than the cycle crossing. However, the difference in detection distance with and without the bicyclist dummy varies over crossings. Only weak correlations between physical parameters and visibility could be shown. The results are the same both at dry and wet road surface. (Author/publisher) This report may be accessed by Internet users at


20101824 ST S [electronic version only]

Linköping, Swedish National Road and Transport Research Institute VTI, 2010, 25 p. + app., 6 ref.; VTI rapport 691A - ISSN 0347-6030

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