The PNCC said it was just awaiting for the "Supplemental Toll Operations Agreement" (STOA) to be signed by concerned agencies for construction to begin.
The STOA will define terms and conditions governing activities to be undertaken at the sites, including time frame as well as the specific roles and obligations of the PNCC, project proponents, Malaysian firm MTD Expressway Inc. and the government.
PNCC officials said initial activities have been conducted in the area four months ago, causing minor traffic buildup.
Advisories to the public will be issued before the road-widening project formally begins so that motorists can take alternative routes.
Charito Chavez, head of the PNCC Corporate Communications Office, earlier confirmed that pavement assessment has been undertaken on Toll Road 2, referring to the route from Alabang to Calamba.
On Toll Road 1, or the Alabang viaduct, an alternative route is also being made in time for its rehabilitation.
The project intends to extend SLEX coverage from Alabang to Calamba by 7.8 kilometers up to Sto. Tomas, Batangas, and connect it to the Southern Tagalog Arterial Road (STAR), which runs through Sto. Tomas town in Batangas.
Chavez admitted that once work is concentrated in the Alabang area, there will be a slowdown of activities.
"But whatever lanes are available now will still be passable to motorists during that time," he said.
Muntinlupa City officials have raised concern over the possible heavy traffic in the area once rehabilitation is carried out. Part of the SLEX expansion work is the rehabilitation and widening of the Alabang viaduct, which has started to develop cracks.
Muntinlupa Mayor Jaime Fresnedi said he hoped that construction work would only take a year, but the PNCC said completion might take at least two years.