New Mombasa 105 East
From Halopedia, the Halo wiki
NM 105 E was a large highway that passed through the city of Mombasa, East African Protectorate, Earth. It ran through a subterranean tunnel beneath Liberty Street of Old Mombasa before rising and connecting to New Mombasa via a bridge. This was the main enterance to the city, and traveling further down the highway would take one straight through Sector B and through the City Centre. The Highways featured numerous emergency doors that would shut in case of emergencies such as a collapse[1].
During the First Battle of Earth in 2552, the highway was heavily damaged during intense fighting between UNSC Marines and Covenant forces. Sections of the tunnels collapsed due to Covenant bombardment, and the Highway's emergency doors were activated. Covenant forces used the highway's bridge to regroup when Liberty Street was retaken by the Marines. A Scarab also followed the Highway into Sector B, until it passed over several buildings and to the Docks.[2]
The underground highway is divided into several sections. During the First Battle of Earth, John-117 passed through the C2, C3, and C4 sections of the highway on the west side of the bridge, on the mainland.[3]