Upon completion, the highway is expected to become one of the two major roads on the island that cross the Cordillera Central mountain range.

The road also crosses barrio Machuelo Abajo, and an interchange with PR-14, which goes to downtown Ponce and Coamo.

The newer freeway alignment briefly continues north but comes to an abrupt end at a temporary terminus, requiring motorists to detour on the narrower PR-5516.

[citation needed] PR-10 continues north, intersecting PR-135, which leads west to Lake Guayo, located between Adjuntas and Lares.

It continues north for approximately 15 miles before reaching another section of new PR-10, just prior to the town of Utuado.

In this stretch, construction of the realigned PR-10 is visible, alternating between the left and right sides of PR-123, as it carves through the mountains.

About one-half mile south of the town of Utuado, PR-123 intersects with PR-603, which connects to another section of realigned PR-10.

Further north the road also intersects PR-621 which leads to PR-146 and Dos Bocas Lake, a major source of hydroelectricity.

Traversing the Central Karst Zone,[15] PR-10 follows a course parallel to Rio Grande de Arecibo.

Continuing north, PR-10 descends from the mountains and enters Puerto Rico's northern coastal valleys.

[16] There is an interchange with PR-22, the main limited access highway on Puerto Rico's northern coast.

PR-123 dates to the late 19th century when it was built under the colonial government of Spain to connect the coffee-growing town of Adjuntas to the port city of Ponce as a farm-to-market road.

To ameliorate the situation, in 1974 the Puerto Rico Department of Transportation and Public Works started planning for the construction this road to connect the cities of Ponce and Arecibo.

[6][23] While one of the main reasons to build the new PR-10 was to facilitate the movement of trucks in the mineral exploitation of the area, such exploitation met with considerable opposition from environmental advocates and today the road is being built to promote other types of socio-economic developments, such as those associated with the Port of the Americas.

The first phase, consisting of 1.24 km of roadway, was completed at a cost of $7.9 million and opened to the public on 21 August 2009.

[11] On 8 November 2010, large rocks fell on a section of the new PR-10 in barrio Tibes leading to a 24-hour closure of the highway.

As a result, the Puerto Rico DTOP is assessing whether the area would be a candidate for the installation of metal nets that would minimize the possibility of further erosion.

[28] The building of the new PR-10 was an issue of contention based on environmental reasons related to the effect on the virgin Cordillera Central.

When a group of American corporations attempted to lease land from the Government of Puerto Rico to exploit nickel, copper and cobalt mines, a grassroots effort by Puerto Rican townspeople had the government turn away from the idea.

No plans have been disclosed to close the old PR-123 after the new PR-10 construction project is complete, and PR-123 will likely serve mostly as a local route.

[6][31] The new highway was anticipated to be completed by 2015 at a cost of $500 million,[6][23] however remains incomplete at the present moment.