Buggy

This is the essential "crazy auto-mobile with mounted gun fun vehicle" of HL2. It's good for covering a lot of ground in a short amount of time, and also has a gaus tau-cannon gun built in at the right side of it with both the primary and alternate fire of the gauss tau-cannon gun found in the original HL.

Air Boat

This is kind of like "the skiing air boat" of HL2, with a machinegun front mounted, it's a great vehicle for covering a lot of distance in water and dangerous hazard water filled areas of HL2, while also manuvering quickly and avoiding enemy fire / damage.