Engineering:Autobesity

From HandWiki

Autobesity, also known as car bloat, truck bloat and carspreading,[1] is the trend, beginning in about the 1990s,[2] of cars increasing in average size and weight.[3][4] The average weight of cars sold in Europe increased by 21% between 2001 and 2022.[5] In the United States, SUVs and pickup trucks comprised more than 75% of new sales in 2024 compared to 38% in 2009.[6]

The driver safety arms race is a phenomenon whereby car drivers are incentivized to buy larger auto-vehicles in order to protect themselves against other large auto-vehicles.[7][8][9][10] This has a spiralling effect whereby cars get increasingly larger, which has adverse overall effects on traffic safety.[11][12] It is an example of a prisoners' dilemma, as it can be individually rational to attain larger vehicles while having adverse outcomes on all traffic users.[13]

Negative consequences

Among the consequences of increased car weight and size are:

  • Poorer air quality, even with electric vehicles, because heavier vehicles have higher energy consumption and release more tyre and brake particles (non-exhaust emissions).[2][14]
  • Reduced road safety, as heavier vehicles have greater kinetic energy, and taller vehicles are more likely to strike pedestrians in the head and torso, or even not be able to see small children who are below the driver's line of sight.[15][16] Additionally, larger vehicles are more likely to hit pedestrians when turning due to poorer visibility.[17][18] Vehicles with higher front ends and blunt profiles are 45% more likely to cause fatalities in crashes with pedestrians than smaller cars and trucks.[6] In the United States, pedestrian fatalities increased by 57% between 2013 and 2022.[19]
  • Parking issues for other vehicles, as they don't fit in typical parking spaces, often occupying multiple spaces.[20]
  • Increased consumption of public space, promoting more sprawling cities and further exacerbating energy and automobile dependency.[21]
  • Heavier vehicles increase road wear.[1]

Positive consequences

  • In a collision, the heavier vehicle will transfer more momentum to the lighter vehicle. This makes the heavier vehicle safer for its occupants, at the expense of making the lighter vehicle more dangerous for the smaller vehicle's occupants.[citation needed]
  • Larger cars are safer for their occupants than smaller ones because they can have longer crumple zones and there is more room between the body and the occupants.[citation needed]
  • Taller cars offer a higher seating position and hence better situational awareness for the driver, although partially offset by other cars also being tall. This also makes it harder for drivers of shorter cars to see.[citation needed]
  • Taller cars tend to have taller door openings, easing entry and exit. Partially offset by the floor also moving upwards, making it a larger step for entry and exit.[citation needed]
  • Larger cars can carry more passengers or cargo.[citation needed]
  • Larger cars are more comfortable for the occupants.[citation needed]

Explanations

The underlying incentive of the arms race is crash incompatibility[citation needed], which refers to the tendency of some vehicles to inflict significantly more damage on another vehicle in a two-car crash. The primary source of this incompatibility is a disparity in mass. A heavier vehicle, such as an SUV or pickup truck, will cause much more serious damage in a crash with a lighter vehicle like a sedan. Research by Michael Anderson and Maximilian Auffhammer suggests that "controlling for own-vehicle weight, being hit by a vehicle that is 1,000 pounds heavier generates a 40-50% increase in fatality risk."[22]

Incompatibility also results from vehicle design. SUVs and pickup trucks often ride higher than cars, and their structural stiffness can be mismatched with smaller vehicles.[23][24] The National Highway Traffic Safety Administration (NHTSA) studies the "aggressiveness" of vehicles, defined as the average injury risk a vehicle imposes on occupants of other vehicles. A 2003 NHTSA study found that, compared to cars, minivans were 1.16 times as aggressive, pickups were 1.39 times more aggressive, and SUVs were 1.71 times more aggressive. When accounting for weight, light trucks (including SUVs) were estimated to be 3.3 times more aggressive than cars in head-on crashes.[25]

An individual driver may choose a large car for personal safety, though it threatens other road users. This in turn pushes others to choose large cars, creating a vicious circle. A US National Safety Council expert described autobesity as an "arms race".[26]

Even though this is a decisive factor that some buyers do take into account, even the ones that don't actively search for larger vehicles are affected due to the increase in the number of safety features from airbags to crumple zones. These require much more space in the vehicle, even adding areas of apparently empty space just so that the bodywork has a larger crumple zone in case of a collision. [27]

Government actions

  • France, Norway, the Netherlands and Washington, D.C. (among others) tax vehicles by weight.[28][29]
  • A 2023 European Parliament report proposes introducing a new "category B+" driving licence for cars heavier than 1,800 kg (4,000 lb).[30]
  • From 2024 Paris will charge higher parking fees for SUVs.[31]
  • In September 2024, the US National Highway Traffic Safety Administration proposed a rule mandating manufacturers to test their vehicles using pedestrian crash test dummies, with an estimate of saving 67 pedestrian lives per year.[19]
  • In 2025, Cardiff council increased the cost of parking permits for vehicles weighing more than 2,400 kilograms (5,300 lb), with plans to lower the weight threshold over time.[1]

References

  1. ↑ 1.0 1.1 1.2 Leggett, Theo (3 December 2025). "'Carspreading' is on the rise - and not everyone is happy about it". BBC. https://www.bbc.com/news/articles/cy7vdvl2531o. 
  2. ↑ 2.0 2.1 Fuller, Gary (8 September 2023). "Autobesity on course to worsen air pollution caused by motoring". The Guardian. https://www.theguardian.com/environment/2023/sep/08/autobesity-on-course-to-worsen-air-pollution-caused-by-motoring. 
  3. ↑ "Researchers warn 'autobesity' trend is on track to endanger health worldwide: 'This rise in fatalities coincides'". October 22, 2023. https://uk.finance.yahoo.com/news/researchers-warn-autobesity-trend-track-114500082.html. 
  4. ↑ Hatch, Patrick (2023-08-05). "Bigger, dirtier, more dangerous: How 'auto-besity' is a health risk for everyone". The Sydney Morning Herald (Australia). https://www.smh.com.au/national/bigger-dirtier-more-dangerous-how-auto-besity-is-a-health-risk-for-everyone-20230803-p5dtkg.html. 
  5. ↑ Anthony, Andrew (November 5, 2023). "Monsters of the road: What should the UK do about SUVs?". The Guardian. https://www.theguardian.com/technology/2023/nov/05/monsters-of-the-road-what-should-the-uk-do-about-suvs. 
  6. ↑ 6.0 6.1 "As cars and trucks get bigger and taller, lawmakers look to protect pedestrians". NPR. https://www.npr.org/2024/08/23/nx-s1-5084276/pedestrian-protection-bill-bigger-cars-trucks. 
  7. ↑ White, Michelle J. (2004). "The "Arms Race" on American Roads: The Effect of Sport Utility Vehicles and Pickup Trucks on Traffic Safety" (in en). The Journal of Law and Economics 47 (2): 333–355. doi:10.1086/422979. ISSN 0022-2186. https://www.journals.uchicago.edu/doi/10.1086/422979. Retrieved 2024-02-18. 
  8. ↑ "Heavy cars and SUVs: The external costs of the vehicle-weight "arms race"" (in en-US). 2013-11-12. https://journalistsresource.org/economics/arms-race-u-s-highways-external-costs-heavier-cars-suvs/. 
  9. ↑ Grabar, Henry (2018-11-30). "The SUV Arms Race" (in en-US). Slate. ISSN 1091-2339. https://slate.com/technology/2018/11/suv-arms-race-pick-up-car-safety-headlights-visibility-crash.html. 
  10. ↑ "Americans’ love affair with big cars is killing them". The Economist. 2024. ISSN 0013-0613. https://www.economist.com/interactive/united-states/2024/08/31/americans-love-affair-with-big-cars-is-killing-them. 
  11. ↑ "SUVs protect drivers, but make everyone else less safe. How do we change that?". CBC. 2022. https://www.cbc.ca/news/canada/british-columbia/about-here-suvs-1.6411168. 
  12. ↑ "Driver safety 'arms race' fuelling boom in gas-guzzling SUVs, says journalist". CBC. 2019. https://www.cbc.ca/radio/thecurrent/the-current-for-nov-1-2019-1.5344114/driver-safety-arms-race-fuelling-boom-in-gas-guzzling-suvs-says-journalist-1.5344145. 
  13. ↑ Tay, Richard (2002). "The Prisoner's Dilemma and Vehicle Safety: Some Policy Implications". Journal of Transport Economics and Policy 36 (3): 491–495. ISSN 0022-5258. https://www.jstor.org/stable/20053916. 
  14. ↑ Zipper, David (July 19, 2023). "EVs Are Sending Toxic Tire Particles Into the Water, Soil, and Air". The Atlantic (US). https://www.theatlantic.com/technology/archive/2023/07/electric-vehicles-tires-wearing-out-particulates/674750/. 
  15. ↑ These Stupid Trucks are Literally Killing Us. Netherlands. March 2023. Retrieved 2023-09-23 – via www.youtube.com.
  16. ↑ "Des voitures plus lourdes, plus hautes et plus puissantes pour une sécurité routière à deux vitesses ?". Belgium: Vias Institute. August 30, 2023. https://www.vias.be/fr/newsroom/des-voitures-plus-lourdes-plus-hautes-et-plus-puissantes-pour-une-securite-routiere-a-deux-vitesses-/. 
  17. ↑ "Editorial: Hulking SUVs and trucks are deadly. We need to encourage safer models". Los Angeles Times (US). April 4, 2023. https://www.latimes.com/opinion/story/2023-04-04/editorial-hulking-suvs-and-trucks-are-deadly-to-pedestrians-why-arent-regulators-pushing-for-safer-models. 
  18. ↑ "SUVs, other large vehicles often hit pedestrians while turning". US: Insurance Institute for Highway Safety. 2022-03-17. https://www.iihs.org/news/detail/suvs-other-large-vehicles-often-hit-pedestrians-while-turning. 
  19. ↑ 19.0 19.1 Hawkins, Andrew J. (2024-09-10). "The US finally takes aim at truck bloat". https://www.theverge.com/2024/9/10/24241047/nhtsa-rule-pedestrian-safety-fmvss-suv-truck-design. 
  20. ↑ Norris, Sian (August 26, 2023). "More than 150 car models too big for regular UK parking spaces". Guardian (UK). https://www.theguardian.com/business/2023/aug/26/more-than-150-car-models-too-big-for-regular-uk-parking-spaces. 
  21. ↑ Medina, Miguel Ángel (2023-09-25). "¿Deben pagar más los coches grandes por aparcar en la calle? En París y Lyon empezarán a hacerlo" (in es). https://elpais.com/clima-y-medio-ambiente/2023-09-25/deben-pagar-mas-los-coches-grandes-por-aparcar-en-la-calle-en-paris-y-lyon-empezaran-a-hacerlo.html. 
  22. ↑ "POUNDS THAT KILL: THE EXTERNAL COSTS OF VEHICLE WEIGHT". National Bureau of Economic Research. January 4, 2012. http://are.berkeley.edu/~mlanderson/pdf/anderson_auffhammer.pdf. Retrieved September 25, 2012. 
  23. ↑ "Relationship of crash test procedures to vehicle compatibility". Society of Automotive Engineers, New York, NY. 2003. http://cat.inist.fr/?aModele=afficheN&cpsidt=16125334. Retrieved September 25, 2012. 
  24. ↑ "You have unmet needs: the psychology behind Australia’s love affair with big cars". The Guardian. 2025-03-15. https://www.theguardian.com/australia-news/2025/mar/15/you-have-unmet-needs-the-psychology-behind-australias-love-affair-with-big-cars. 
  25. ↑ "National Highway Traffic Safety Administration report on vehicle compatibility". http://www.nhtsa.dot.gov/cars/rules/regrev/evaluate/pdf/809662.pdf. 
  26. ↑ Zipper, David (2022-11-07). "The Car Safety Feature That Kills the Other Guy". Slate (US). https://slate.com/business/2022/11/suv-size-truck-bloat-pedestrian-deaths.html. 
  27. ↑ "How Vehicle Safety Has Improved Over the Decades | NHTSA". https://www.nhtsa.gov/how-vehicle-safety-has-improved-over-decades. 
  28. ↑ Alter, Lloyd (2023-09-08). "Car bloat is getting ridiculous and must be stopped". https://lloydalter.substack.com/p/car-bloat-is-getting-ridiculous-and. 
  29. ↑ Vaughan, Adam Vaughan (2023-11-06). "Tax SUVs by weight like France and Norway, say green campaigners". https://www.thetimes.com/uk/environment/article/tax-suvs-by-weight-like-france-and-norway-say-green-campaigners-8kg5pz5l0. 
  30. ↑ "Draft report on the proposal for a directive of the European Parliament and of the Council on driving licences, amending Directive (EU) 2022/2561 of the European Parliament and of the Council, Regulation (EU) 2018/1724 of the European Parliament and of the Council and repealing Directive 2006/126/EC of the European Parliament and of the Council and Commission Regulation (EU) No 383/2012". European Parliament. 2023-07-19. https://www.europarl.europa.eu/doceo/document/TRAN-PR-750248_EN.pdf. 
  31. ↑ Willsher, Kim (July 11, 2023). "Paris to charge SUV drivers higher parking fees to tackle 'auto-besity'". The Guardian. https://www.theguardian.com/world/2023/jul/11/paris-charge-suv-drivers-higher-parking-fees-tackle-auto-besity. 



Retrieved from "https://handwiki.org/wiki/index.php?title=Engineering:Autobesity&oldid=4556155"