Interesting. I did not consider the difference between local traffic and other traffic when upgrading these roads to trunk roads. I now wonder if Rainbow Boulevard would be classified as a trunk road or primary road. On the one hand, locals tend to use it more than other primary/secondary roads around the area, such as Buffalo and Jones. On the other hand, Rainbow Boulevard doesn't link Las Vegas to any other cities outside the Valley, if you exclude its freeway links (Summerlin Parkway, US 95/I-11, CC 215/Future I-215). What would be the correct classification for Rainbow Boulevard?