Pan-American Highway
The Pan-American Highway is a network of roads stretching across the American continents and measuring about in total length. Except for a rainforest break of approximately , called the Darién Gap, the roads link almost all of the Pacific coastal countries of the Americas in a connected highway system. According to "Guinness World Records", the Pan-American Highway is the world's longest "motorable road". However, because of the Darién Gap, it is not possible to cross between South America and Central America with conventional highway vehicles. Without an all-terrain vehicle, it is necessary to circumnavigate this terrestrial stretch by sea.
Pacific Highway (United States)
Good roads advocate and road-building pioneer Sam Hill was perhaps the main motivating force behind building the original Pacific Highway as a "national auto trail"; from Blaine, Washington, on the Canada–US border, where he would build his Peace Arch, through Oregon to the Siskiyou Mountains of northwestern California. The road was built in the early 20th century—long before the U.S. Highway System was established. In 1923, its of pavement made it the longest continuous stretch of paved road in the world at the time. The Pacific Highway later extended north to Vancouver, British Columbia, and south through San Francisco to San Diego in Southern California.