The Washington DC transit agency WMATA has now released drafts of its new network map, which highlight the frequent network very dramatically with wide red lines:
Finally, it's possible to quickly see where the next bus is coming soon, rather than getting lost in a confusing tangle in which all routes look equally important. The map is by the excellent firm CHK America. Get the full story, with many more samples, at Greater Greater Washington, and remember, if you like these, don't take it for granted. Transit agencies need to hear positive feedback where it's deserved.