Puerto Rico Highway 52 (PR-52), a major toll road in Puerto Rico, is also known as Autopista Luis A. Ferré. It was formerly called Expreso Las Américas. It runs from PR-1 in southwest Río Piedras and heads south until it intersects with highway PR-2 in Ponce. At its north end, the short PR-18 continues north from PR-52 towards San Juan. This short segment is known as Expreso Las Americas, the only segment of the route still unofficially bearing this name, since PR-18 is officially named Roberto Sánchez Vilella Expressway. The combined route of PR-18 and PR-52 runs concurrent with the unsigned Interstate Highway PRI-1. Toll stations are located in San Juan, Caguas, Salinas, Juana Díaz, and Ponce.
Puerto Rico Highway 18 (PR-18) is a freeway in Puerto Rico, which is also known as Expreso Las Américas. It runs from its north end at its intersection with PR-22 in San Juan to its south end in Río Piedras where it intersects with PR-1. At this point PR-18 becomes PR-52, known as Autopista Luis A. Ferré.
Puerto Rico Highway 30 (PR-30), known as Expreso Cruz Ortiz Stella, is a main freeway in Puerto Rico which connects the city of Caguas to the town of Humacao.
Puerto Rico Highway 3(PR-3) at nearly 100 miles long, is the second longest highway on Puerto Rico. It connects the San Juan neighborhood of Río Piedras to downtown Salinas indirectly around the eastern coast of the island. Highway 3 ranges from a three lane urban avenue in San Juan to a one lane rural road past Fajardo. While other roads connect San Juan, it runs the coastline of Puerto Rico east of San Juan, beginning in Río Piedras near Santurce and goes to Fajardo where it goes south paralleling the coastline to Humacao and Maunabo. It goes up to a mountain-scenic route and goes west to Salinas, where it meets PR-1.
Puerto Rico Highway 60 (PR-60) or Avenida Dionisio Casillas is a 1.9-mile-long (3.1 km) freeway entirely located in Humacao, Puerto Rico. It connects Puerto Rico Highway 30 to Puerto Rico Highway 3 and has two exits:
Puerto Rico Highway 111 (PR-111) is a highway connecting Aguadilla, Puerto Rico at Puerto Rico Highway 2 and Puerto Rico Highway 115 to Utuado, Puerto Rico at Puerto Rico Highway 140.
Puerto Rico Highway 65 (PR-65) is a short highway connecting Puerto Rico Highway PR-239, also locally known as Alfonso Valdés Cobián Boulevard near University of Puerto Rico at Mayagüez, to Puerto Rico Highway 106. It has not an intersection to the main highway PR-2, but can be accessed quickly going west of the alt route. It is also the main highway to the Palacio de Recreación y Deportes and to the Parque de los Próceres.
Puerto Rico Highway 203 (PR-203), also known as the Expreso Chayanne, is a highway which connects Gurabo, Puerto Rico at PR-30 with its parallel route Puerto Rico Highway 183 in San Lorenzo. It is the main route to San Lorenzo and is about 7 kilometers long. It is a dangerous highway, as steep grading is present going down and then going up.
Puerto Rico Highway 17 (PR-17) is a main highway located in Carolina, San Juan and Guaynabo, Puerto Rico. It begins at PR-20 near its terminus with PR-2, and ends in the Luis Muñoz Marín International Airport in Carolina. It is known as Jesus de Piñero Avenue along its entire length.
Puerto Rico Highway 21 (PR-21) is the main highway to get to the Medical Center and Veterans Hospital in San Juan, Puerto Rico. It begins in PR-19 in Guaynabo to San Juan before ending in PR-1.
Puerto Rico Highway 149 (PR-149) is a secondary highway in Puerto Rico that connects the towns of Manatí in the north coast of Puerto Rico, from PR-22 to Juana Díaz in the south coast, ending at PR-1. It goes through Ciales, and is a divided highway and a wide rural highway between that municipality and Manatí, as it is also from Juana Díaz to Villalba. From Ciales to Villalba, it is an extremely dangerous mountain road, with very high areas and poor safety barriers. From Ciales to Villalba it passes through the Salto de Doña Juana, a spot with a small waterfall and a small creek where people can jump and swim. It is one of the longest highways going south to north, perhaps the longest excluding PR-1 and PR-52.
Puerto Rico Highway 198 (PR-198) is a 15-kilometre-long (9 mi) highway that parallels Puerto Rico Highway 30 from Juncos, Puerto Rico, to Humacao, Puerto Rico, where it ends at Puerto Rico Highway 3. Like Puerto Rico Highway 189, it passes through the business centers of Juncos, Las Piedras and Humacao.
Puerto Rico Highway 183 (PR-183) is a main highway which begins in the downtown/business area of Caguas, near Puerto Rico Highway 1 and ends in Puerto Rico Highway 198 in Las Piedras. Measuring near 25 kilometers, it is real rural parallel road of Puerto Rico Highway 30, though it goes significantly south of the latter and the only municipality it does not go through which PR-30 does in Humacao. PR-183 can be accessed by two connectors from PR-30; PR-203 from Gurabo to San Lorenzo, and PR-204 (future) in Las Piedras, and they make their only direct intersection in Las Piedras. It is two-lane per direction in Caguas and becomes rural in the municipality just before entering San Lorenzo, and after its confusing intersection with PR-203 it becomes a small two-lane per direction again for about 4 kilometers, and then becomes rural for the rest of its length.
Avenida Juan Ponce de León, coextensive as Route PR-25 along its entire length, is one of the main thoroughfares in San Juan, Puerto Rico.
The Carretera Central is a historic north–south central highway in Puerto Rico, linking the cities of San Juan and Ponce by way of Río Piedras, Caguas, Cayey, Aibonito, Coamo, and Juana Díaz. It crosses the Cordillera Central. Plans for the road started in the first half of the 19th century, and the road was fully completed in 1898. At the time the United States took possession of Puerto Rico in 1898, the Americans called it "the finest road in the Western Hemisphere."
Puerto Rico Highway 142 (PR-142) is a road that connects the northern region of Puerto Rico with the municipality of Corozal, extending from PR-2 in Dorado to PR-159 near downtown Corozal.
Puerto Rico Highway 124 (PR-124) is a rural road that connects from Lares to Las Marías.
Puerto Rico Highway 47 (PR-47), also known as Calle De Diego, is an urban road in Río Piedras, Puerto Rico.
Puerto Rico Highway 34 (PR-34) is an urban road located in Caguas, Puerto Rico. This road extends from Avenida José Garrido (PR-196) in Cañabón barrio to PR-183 in Tomás de Castro barrio, and is part of Turabo and Degetau avenues.
Puerto Rico Highway 27 (PR-27) is a north–south avenue located in San Juan, Puerto Rico, known as Avenida José Celso Barbosa. This highway extends from Avenida 65 de Infantería (PR-3) to Avenida Borinquen (PR-36) in Santurce, east of downtown Río Piedras and Hato Rey.
PR-183 in Montones 
PR-30 in Montones–Ceiba 
PR-198 in Montones–Quebrada Arenas 
