Abstract: Some effective measures should be undertaken during the conceptual design of grille shading sheds to reduce the stroboscopic effect and improve the drivers′ driving comfort degree. First, the effect of seasonal variation of solar radiation on the grille stroboscopic wave is examined based on a theoretical model of solar radiation. Second, the stroboscopic effect visibility measure (SVM) index is introduced to quantify the stroboscopic effect induced by the stroboscopic wave under the grille shading shed subjected to strong solar radiation. Third, the SVM is used to examine the effects of grille period, brightness duty cycle, and modulation depth on the stroboscopic effect in grille shading sheds. Finally, in a practical engineering case, an optimal design for reducing the stroboscopic effect of the grille shading sheds is proposed. The findings are as follows: (1) The SVM is related to the grille period and the intensity of solar radiation, but not to the incident angle. (2) The SVM is closed to modulation depth within a certain range of the grille period, while the effect of the brightness duty cycle on the SVM can be ignored.

Key words: highway tunnel, grille shading shed, stroboscopic effect visibility, grille period, modulation depth