which car owners actually have the filthiest interiorsThe dirtiest cars in America belong to Hyundai, Nissan, and Jeep owners, according to a new study measuring filth three separate ways.1,004 American drivers were surveyed about their in-cabin behavior and roughly 2.7 million words were analyzed across 13 brand subreddits to compare what drivers do, what other drivers assume, and how owners talk among themselves.which car owners actually have the filthiest interiorsTo rank the brands, Panda Hub, a car detailing service provider, built what it calls a Filth Index, averaging the share of owners who admitted to each of 12 behaviors. Hyundai topped the list at 43.6, followed by Nissan (42.2) and Jeep (41.8). Ford (41.3) and Subaru (41.2) rounded out the worst five, while Mazda owners came out cleanest at 32.7. Honda and Toyota, brands often associated with practical ownership, landed in the middle of the pack.AdvertisementAdvertisementThe underlying behaviors range from near-universal to rarely confessed. Some 93% of drivers admitted to passing gas behind the wheel, 56% to picking their nose, and 53% to eating a full meal in the car. Just over half have left trash sitting for a week or more. Further down the list, 28% have vomited in the car, 23% have urinated in or just outside it, and 22% have had sex in it. Roughly 1 in 5 have slept overnight in their vehicle, and 9% have masturbated in it.which car owners actually have the filthiest interiorsThe brand-by-behavior splits get specific. Nissan owners led on vomiting (44%), Hyundai owners on both urinating (35%) and having sex (35%), and Jeep owners on sleeping overnight (41%). Subaru owners topped the masturbation figure at 17%, well above the 9% national average. Demographics shaped much of the data: 70% of Gen Z have eaten a sit-down meal in the car, sex skewed both young and male, and men were more likely than women to have slept overnight or masturbated in their vehicles.Reputation, however, told a different story. When Panda Hub asked drivers which brands are dirtiest, they named Ford, Chevrolet, Honda, Nissan, and Dodge. The cleanest votes went to BMW, Mercedes-Benz, Porsche, Jaguar, and Lexus, a list that climbs straight up the price ladder. Hyundai, the actual Filth Index leader, did not crack the perceived dirtiest five.which car owners actually have the filthiest interiorsAmericans appear aware they are being judged. Some 64% have assessed someone's personality by their car's interior, and 76% have cleaned their car before a date, job interview, or family visit. Nearly half have hidden trash or smells before a passenger got in, and 18% have lied about their car's condition to avoid giving a ride. Gen Z ran the most elaborate cover operations, with 57% hiding evidence and 29% treating the cabin as a private space where normal rules do not apply.AdvertisementAdvertisementThe third measure, how owners talk online, produced yet another leader. Honda owners cursed most often, at 9.7 profanities per 10,000 words in their subreddit, ahead of Dodge (7.7), Subaru (6.6), and Tesla (6.3). Volkswagen owners were the tamest at 3.8.Become an AutoGuide insider. Get the latest from the automotive world first by subscribing to our newsletter here.