{"version": "1.0", "type": "rich", "title": "The Logic To American Interstate Highway Numbering", "author_name": "kontextmaschine", "author_url": "https://kontextmaschine.com", "provider_name": "kontextmaschine", "provider_url": "https://kontextmaschine.com", "url": "https://kontextmaschine.com/post/621737777896226816/", "html": "<h1>The Logic To American Interstate Highway Numbering</h1><ul><li><b>Odd numbers</b> are <i>North-South routes</i>. Numbers increase west-to-east, original backbone routes are on the <b>5s</b>. (ex. I-5, I-95)</li><li><b>Even numbers</b> are <i>East-West routes</i>. Numbers increase south-to-north, original backbone routes are on the <b>10s</b> (ex. I-10, I-80)</li><li><b>Three-digit numbers</b> with <b>even first digit</b> are <i>loops</i> that connect to their parent Interstate (the last two digits) <i>twice</i>, to avoid cities or serve an alternate route (ex. I-405 in LA, I-276 in Philadelphia)</li><li><b>Three-digit numbers</b> with <b>odd first digit</b> are <i>spurs</i> that cross their parent Interstate (the last two digits) <i>once</i>, though they may head off in both directions</li></ul><p>Thanks, Dwight Eisenhower!</p>"}