| 摘要 |
An improved roadway sign (2) comprising a light retroreflective indicia region and colored retroreflective background region is provided. The retroreflective properties of the regions are selective such that the ratio of the retroreflective brightness of the indicia to that of the background is substantially larger at observation locations within the legibility zone (8) for the sign, than the ratio is at observation locations outside (12) the legibility zone. The sign is conspicuous by virtue of the bright retroreflection and distinctive color of the background outside the legibility zone, yet is legible because of the increased contrast ratio of the indicia to the background in the legibility zone. |
