Which interstate connects Los Angeles to Phoenix?

The interstate that connects Los Angeles to Phoenix is I-10. This route is a major east-west highway running from California to Florida, with a significant segment traversing southern California and Arizona. When traveling from Los Angeles to Phoenix, I-10 provides a direct and efficient route, facilitating the movement of both personal and commercial traffic between these two major cities.

In contrast, the other interstates mentioned serve different geographic purposes or routes. I-15 primarily connects southern California to Las Vegas and points north, I-5 runs up the California coast and is a primary route for northwest-southeast travel, while I-8 extends from San Diego to Casa Grande, Arizona, but does not serve as a direct link between Los Angeles and Phoenix. Therefore, I-10 is the most appropriate choice for this connection.