NLEX Harbor Link

NLEX Harbor Link (North Luzon Expressway Harbor Link), signed as E5 of the Philippine expressway network, is a four- to six-lane expressway that serves as a spur of North Luzon Expressway (NLEX) linking it to the Port of Manila to the west and Quezon City to the east. It runs from Katipunan (a component of Circumferential Road 5) and C.P. Garcia Avenues in Quezon City to Radial Road 10 in Navotas, leading to the Port of Manila. Currently, its segment from Mindanao Avenue in Valenzuela to Navotas is operational.

The NLEX Harbor Link Project is an extension of the North Luzon Expressway running from Mindanao Avenue in Valenzuela at the east to Radial Road 10 in Navotas at the west, allowing access to the Port of Manila. It aims to connect with the Port of Manila while improving cargo movement between NLEX and Radial Road 10. It is divided into four segments, namely: Segment 8.1 (Mindanao Avenue Link), 8.2 (C-5 Link / Citi Link), 9 (Karuhatan Link), and 10 (Harbor Link). It forms part of the expressway's open section. Both Segments 8.1 and 9, located in Valenzuela, are components of Circumferential Road 5 (C-5) of Manila's arterial road network.

NLEX Segment 8.1 (Mindanao Avenue Link) is a four-lane, 2.7-kilometer (1.7 mi) expressway from the Harbor Link Interchange to Mindanao Avenue in Valenzuela. Lying on the ground level east of the interchange, it begins at the intersection with Mindanao Avenue in Barangay Ugong and then approaches the Mindanao toll plazas, widening to 6 lanes serving only westbound traffic. It terminates at the Harbor Link Interchange with NLEX Main and continues to the west as Segment 9 (Karuhatan Link).

NLEX Segment 9 (Karuhatan Link) is a four-lane, 2.42-kilometer (1.50 mi) expressway from Harbor Link Interchange to MacArthur Highway in Karuhatan, Valenzuela. It is the first segment of the NLEX Harbor Link project. It begins at the Harbor Link Interchange with NLEX Main, picking up from where Segment 8.1 (Mindanao Avenue Link) left off. Lying on the ground level west of the interchange, it then traverses Barangays Gen. T. De Leon, Parada, and Maysan, where two exits towards the first two barangays, respectively, are found. It then enters Barangay Karuhatan, where it approaches the Karuhatan toll plaza, widening to 6 lanes serving only eastbound vehicles, and Segment 10 (Harbor Link) and finally terminates at MacArthur Highway.

NLEX Segment 10 (Harbor Link), the second phase of the NLEX Harbor Link project, is a four-lane, 5.65-kilometer (3.51 mi) fully elevated expressway which connects with the Karuhatan Link (Segment 9) in Valenzuela to C-3 Road in Caloocan, where two ramps carry it to the west for another 2.60 kilometers (1.62 mi) up to Radial Road 10 (R-10) in Navotas. It begins at Karuhatan Exit with Segment 9 (Karuhatan Link) and MacArthur Highway. The section near the northern terminus traverses an industrial and residential area, which necessitated the demolition of numerous houses, buildings, and warehouses. It soon follows the railway right of way, where it rises to as high as 19 meters (62 ft) to provide necessary ground clearance for the viaduct carrying the future North–South Commuter Railway of the Philippine National Railways (PNR). This project faced conflicts because of right of way problems, resulting in only one structure being constructed. It then crosses the Tullahan River, where it enters Malabon. It then enters Caloocan, where past Samson Road and the PNR rolling stock shops in Caloocan, it shifts east of the railway's ROW, necessitating the demolition of a wet market. An exit to C-3 Road could then be found before meeting the Caloocan Interchange, where the expressway veers west as the C3–R10 spur alignment with a connection to NLEX Connector that would lead southwards to Manila. The 2.60-kilometer (1.62 mi) C3–R10 spur section, also known as the Mel Lopez Boulevard section, runs above C-3 Road, with a westbound exit to Dagat-Dagatan Avenue, crossing the Navotas River as it enters Navotas before reaching the Navotas Interchange, which connects to the Port of Manila via Mel Lopez Boulevard.

At the Navotas Interchange, the expressway has a possible future connection to the proposed Southern Access Link Expressway (SALEX) towards Manila–Cavite Expressway (CAVITEX) or New Manila International Airport, respectively.

According to differing versions of Frost Plan for Quezon City (the then-capital of the Philippines), an avenue was planned to connect the second National Government Center at Constitution Hill (now Batasan Hills) to both Balintawak and Manila North Road (now MacArthur Highway) in Valenzuela. This road was named Republic Avenue or Avenue of the Republic. However, the avenue was partially realized, and its right of way was eventually occupied by informal settlements. The proposal for the Circumferential Road 5 (C-5) came thereafter, with a proposed terminus by the Manila Bay in Navotas, based on a 1980 feasibility study by the Japan International Cooperation Agency.

Another study was conducted by JICA in 1993, which included a plan for an urban expressway in Metro Manila. The planned routes were included in the study. The portion of Expressway Route C-3 would start at the interchange with Expressway Route R-9 along the intersection of Andres Bonifacio Avenue in Quezon City and continue to the first segment of Expressway Route R-10 in Navotas.