The ‘Optical Dot System’ (ODS), originally developed by the principal author, is a ‘Sequence Design’ (SD) to improve vehicle safety by controlling the speed with a layout of oval-shaped road markings for highway and rural roads. The long lasting effectiveness has been proven for cars, as cited in previous research in 2012. However, in shared roads, the frequent occurrences of bicycle accidents involving pedestrians are a serious issue. In Japan the ownership rate of bicycles is one in 1.5 persons (2007); this is quite high compared to the ownership level in the Netherlands and Germany. In order to address this problem, ODS was resized to be adopted for bicycles. In this research, we performed the subject test at an actual site with cyclists, cycling a downward grade in vertical alignment on a long bridge. The test section was composed of three different road markings: ‘ODS/large’, ‘ODS/small’, ‘traversal line’, with ‘plain’; no markings, as the comparison criteria. The results showed that the cycling speeds on ODS sections were significantly decreased, while, the ‘traversal line’ had no speed control effect, as was the case with the ‘plain’ road. The subjects were instructed to cycle at pleasant, smooth speed, but they were not aware of being controlled by ODS. Significant effectiveness of ODS was proven for autonomously controlling bicycle speed.