San Marino is being the top country by road density in the world. As of 2011, road density in San Marino was 583.8 km/100 sq.km that accounts for 7.90 % of the world's road density. The top 5 countries (others are Bahrain, Belgium, Singapore, and Netherlands) account for 33.00 % of it. The world's total road density was estimated at 7,389.5 km/100 sq.km in 2011.
Road density is the ratio of the length of the country's total road network to the country's land area. The road network includes all roads in the country: motorways, highways, main or national roads, secondary or regional roads, and other urban and rural roads.