Where is NLEX and SLEX?

Could you please provide me with some context about the locations of NLEX and SLEX? Are they highways, roads, or some other form of transportation infrastructure? If they are highways, could you specify in which country or region they are located? Additionally, are there any notable landmarks or features nearby that might help in identifying their exact whereabouts? I'm eager to learn more about these locations and how they may relate to my travels or interests.