| 摘要 |
Road marker in a road bed having at the road level a resilient diaphragm carrying a light-reflective lens yieldingly projecting above the road level and operationally depressible below the road level by an automotive wheel passing over the lens, with the diaphragm providing opposite wiper blades extending at the road level into contact with opposite faces of the lens and cleaning these faces on operational depression of the lens below, and its recovery into projection above, the road level.
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