The High Woodlands Highway was a series of roads in South America. It connected the power station with the marketplace.
After Liquid Ocelot attempted to hijack the Sons of the Patriots system with Solid Snake's DNA, Snake, Naomi Hunter, and Drebin ended up fleeing from the now mindless Pieuvre Armement PMC unit. They broke through a gate at the power station to get to the highway, and after evading Gekko and an MGS Stryker, they managed to arrive at the marketplace.
Behind the scenes
High Woodlands Highway is a location that appears in Metal Gear Solid 4: Guns of the Patriots, during Act 2, Solid Sun. It is played solely on-board Drebin's Stryker, where the player must fend off enemy troops and Gekko, with the Stryker's gun turret available for use.