Final answer:
Three-number routes with an even first number typically represent bypasses or beltways in the U.S. Interstate Highway System, circling around a city rather than leading directly into it.
Step-by-step explanation:
In the context of U.S. highways, when a three-number route has an even first number, it usually indicates that the route is a bypass or beltway. This is part of the Interstate Highway System's numbering scheme, where these routes circle around a city or metropolitan area instead of leading directly into it, like routes with odd first numbers often do. For example, I-285 is a beltway around Atlanta, indicating that it does not lead directly into the city center but rather encircles it, allowing for travel around the outskirts of the city