Highway 1

• United States Highway 1
• California State Route 1, better known as Highway 1

Many U.S. states have state routes numbered 1. Hawaii also has an interstate highway numbered Interstate H-1.

The coastal highway joining Australia's mainland state capitals is also termed Highway 1 (though it is not always the primary route between them). Highway 1 circumnavigates the entire Australian continent, making it the longest numbered highway in the world. Some stretches across the Nullarbor Plain and along the north-western coastline are quite isolated, with roadside settlements supporting the passing traffic the only human activity for thousands of kilometres. Still other stretches are high-speed high-capacity expressways with six lanes or even more such as Brisbane's Gateway Motorway, Sydney's Eastern Distributor and Melbourne's Monash Freeway. Average daily traffic counts on Australia's Highway 1 range from as few as 500 vehicles to over 100,000 vehicles every day.