Hummers are real land vehicles that have some features of the military's Humvee, but are designed for civilian use. They are seen in the Season Sixteen episode, "Obama Wins!", where they are shown attempting to be sold by Stevenson's Hummer.
Stevenson's Hummer is having a sales event, called 'Rockvember Sales Event', in a seemingly desperate attempt to sell the "gas-guzzling" vehicles. Due to the rising cost of gasoline in the United States, individuals are implied to be less likely to purchase Hummers. As a result, those driving a Hummer are said to have not been seen since 2010.
Obviously clouded by lack of sales and failing business, the Hummer Salesman sees anyone visiting the car lot, for any reason, as someone wanting to purchase a vehicle. This clouded viewpoint includes General Tso and his cohorts, the Park County Police Force, and the boys. Although all of these people have visited the dealership, not a single Hummer was shown being sold.
- Despite Hummer discontinuing the production of new vehicles in 2010, it appears in the South Park Universe they are still being made; the salesman claims to be selling 2014 models.