World Main Highway and Primary Road Network

World Main Highway and Primary Road Network

Source: Road data from Meijer, J.R., Huijbregts, M.A.J., Schotten, C.G.J. and Schipper, A.M. (2018): Global patterns of current and future road infrastructure. Environmental Research Letters, 13-064006. Data is available at

Even if the world road network appears to be connected and rather extensive, it is more a collection of national networks with limited cross-border connections. The only notable exceptions are Europe, where there is a strategy to establish a Trans-European Network (TEN), and North America, where the Canadian and American highway systems are well connected. In recent years, China has also constructed an extensive network of national highways.

On the global scale, 35% of the roads are paved, and 50% have year-round accessibility. Most paved roads are found in North America and Europe, whereas most unpaved and only seasonally accessible roads are found in South America and Africa. The quality and capacity of the road infrastructure vary substantially, which is reflected in transportation costs. For instance, transportation by truck is much cheaper in the United States than in China despite lower labor costs. While a truckload would cost about $1.10 per kilometer to be moved in the United States, it would cost about $1.75 per kilometer to be moved in China.

There is a positive relationship between the length of a national road system and GDP per capita, and population density. Although the United States and Canada have low road density levels compared to Japan and Western European countries, they have high road length per capita. Therefore, their extensive territories mask substantial efforts to provide road infrastructure on a per capita basis, a factor associated with high levels of automobile ownership.

Although Japan is the country among those selected that has the largest share of its land area devoted to road transportation (3.5%), it is Canada that allocates the largest amount of space per capita to the automobile (734 square meters per person), followed by the United States (573). While the percentage of total land area used by the car indicates density and economic intensity, land area per capita figures indicate car dependency. In the United States, about 155,000 square kilometers are reserved for car use, which equals 10% of all the available arable land. Even if total area values are relatively small, roads and parking facilities are dominantly concentrated in urban areas.