In which direction do routes marked by even numbers generally run?

Routes marked by even numbers typically run east to west. This system is part of the grid layout used for interstate highways in the United States, where odd-numbered routes generally run north to south, and even-numbered routes cover the east-west direction. The even-numbered routes provide a clear guideline for drivers, enabling them to navigate efficiently across various states and regions. This organization helps in understanding the overall flow and layout of the highway system, making travel planning simpler.