Highway
Major highways are often named and numbered by the governments that typically develop and maintain them. Australia's Highway 1 is the longest national highway in the world at over and runs almost the entire way around the continent. China has the world's largest network of highways followed closely by the United States of America. Some highways, like the Pan-American Highway or the European routes, span multiple countries. Some major highway routes include ferry services, such as U.S. Route 10, which crosses Lake Michigan.
National Highway System (United States)
According to the Federal Highway Administration, the National Highway System includes roads important to the United States' economy, defense, and mobility, from one or more of the following road networks (specific routes may be part of more than one sub-system):The system includes 4% of the nation's roads, but carries more than 40% of all highway traffic, 75% of heavy truck traffic, and 90% of tourist traffic. All urban areas with a population of over 50,000 and about 90% of America's population live within of the network, which is the longest in the world.