Puerto Rico Highway 20 or PR-20 (Expreso Martinez Nadal) is a short freeway entirely located in Guaynabo, Puerto Rico

Guaynabo, Puerto Rico

Guaynabo is a municipality in the northern part of Puerto Rico, located in the northern coast of the island, north of Aguas Buenas; south of Cataño; east of Bayamón; and west of San Juan...

. It used to be divided highway with traffic signals, which even turned into a rural road near its south end, but due to the traffic congestion in parallel freeway PR-18, and also in PR-1

Puerto Rico Highway 1

Puerto Rico Highway 1 connects the city of Ponce to San Juan. Leaving Ponce, the road follows somewhat parallel along the southern coast of the island and, at Salinas, it turns north to cut through the Cordillera Central in its approach to San Juan....

 and PR-52, it had to be converted and is now near 15 kilometers long. It has few exits; the first being to PR-169, a road to the rural area of Guaynabo and part of Aguas Buenas, Puerto Rico

Aguas Buenas, Puerto Rico

Aguas Buenas, commonly known as "La Ciudad de las Aguas Claras" or "the city of clear waters, is a municipality of Puerto Rico located in the Central Mountain Range, north of Cidra, south of Bayamón, Guaynabo and San Juan; east of Comerio; and north-west of Caguas...

; PR-199 which connects it to PR-1 and PR-52; PR-177 which serves Bayamón and Cupey, and PR-17 (Ave. Piñero). It begins in the Muda sector of PR-1 and ends near San Patricio in Caparra, Guaynabo, at PR-2

Puerto Rico Highway 2

Puerto Rico Highway 2, the longest highway in the Commonwealth of Puerto Rico at about 156 miles long, connects San Juan to Ponce....

. It is tolled going north from PR-1, but not in the other direction.