The current network of highways that connect San Juan to the rest of Puerto Rico were constructed after the occupation by the United States.
Within San Juan, the transportation network centers around the corridor between Rio Piedras and Old San Juan (Avenida Ponce de Leon). Traffic is currently one of the city's major concerns, as physical barriers such as water and swamps make high-density travel to and from the city center difficult. As modern as any other American city, the San Juan urban area boasts two airports and a vast network of multiple lane roads.
Before the age of mass car transit, the primary modes of transportation in San Juan were walking and a tram system that connected San Juan and Rio Piedras via Santurce. The ability of most Puerto Ricans to afford cars as well as the sprawl of the city were both factors in this dependence on personal vehicle transportation.