Gearbox's Tunnels
Honestly i didn't know how to name this prefab
These are the road tunnels made in Gearbox's Mapping style, seen in Opposing Force and Blue Shift. Made into Prefab Kit by me, created from scratch by taking references from decompiled maps.
Curved ones are made with Map2Curve, by Gibshooter (aka ToTac)
May not be 100% accurate.