Bumper (automobile)

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For other uses, see Bumper.
Chromed plated front bumper on a 1958 Ford Taunus
Detail of a rear bumper with integrated tail lamps and a rubber faced bumper guard

In automobiles, a bumper is usually a metal bar or beam, attached to most vehicle's front and rear ends, designed to absorb impact in a minor collision, ideally minimizing repair costs. [1]

Bumpers also have two safety functions, minimizing height mismatches between vehicles and protecting pedestrians from injury.


A BMW front bumper cover (highlighted in red)

Bumpers were originally a rigid metal bar. Current design practice is for the bumper structure on modern automobiles to consist of a plastic cover over a reinforcement bar made of steel, aluminum, fiberglass composite, or plastic.[2]

Specialized bumpers, known as Bull bars or 'roo bars, protect vehicles in rural environments from collisions with large animals.

Pedestrian safety[edit]

Bumpers are increasingly being designed to mitigate injury to pedestrians struck by cars, such as through the use of bumper covers made of flexible materials. On front-end bumpers especially, designers have lowered them, and have used softer materials, such as foams and crushable plastics to reduce the severity of impact on legs.[3]

Height mismatches[edit]

Impact above bumper level

The height and placement of bumpers may be legally specified, to ensure that when vehicles of different heights are in an accident, the smaller vehicle will not slide under the larger vehicle - highly lethal underride collisions, in which a smaller vehicle, such as a passenger sedan, slides under a larger vehicle, such as a tractor-trailer. . Following the 1967 death of actress Jayne Mansfield in an auto/truck accident, US trucks were required to be fitted with Underride guards or Mansfield Bars. [4] The platform bed of a typical tractor trailer is at the head height of seated adults in a typical passenger car, and can cause severe head trauma in even a moderate speed collision.

In addition, modest mismatches between SUV bumper heights and passenger car side door protection have allowed serious injuries at relatively low speeds.[5] NHTSA is currently studying this issue. [6]

Repair costs of passenger car/SUV collisions can be significant due to the height mismatch. [7] This damage can result in vehicles being so severely damaged that they are inoperable after low speed collisions. [8]

Bumpers cannot protect against moderate or high speed collisions, but their height from the roadway surface is important in engaging other protective systems such as energy-absorbing crush zones and airbags.[why?][citation needed][dubious ]

Repair cost publicity[edit]

In the United States, the Insurance Institute for Highway Safety, subjects vehicles to low speed barrier tests (6 mph/10kph) and publicises the repair costs. [9] This counteracts the Market failure that would exist if consumers were not able to choose cars based on better/worse repair costs. Car makers that do well in these in these tests will publicize them. [10]

As an example, in 1990, IIHS conducted four crash tests on three different-year examples of the Plymouth Horizon. The results illustrated the effect of the changes to the US bumper regulations (repair costs quoted in 1990 United States dollars):[11]

  • 1983 Horizon with Phase-II 5-mph bumpers: $287
  • 1983 Horizon with Phase-I 2.5-mph bumpers: $918
  • 1990 Horizon: $1,476


In most jurisdictions, bumpers are legally required on all vehicles.

Regulations for automobile bumpers have been implemented for two reasons - to allow the car to sustain a low-speed impact without damage to the vehicle's safety systems and to protect pedestrians from injury. These requirements are in conflict - 'strong' bumpers minimize economic damage, while 'soft' bumpers minimize injury. [12]

Although a vehicle's bumper systems are designed to absorb the energy of low-speed collisions and help protect the car's safety and other expensive components located nearby, most bumpers are designed to meet only the minimum regulatory standards.[13]

United States[edit]

First standards[edit]

71 Dart Front Bumper L.jpg 74 Valiant Front Bumper.jpg
71 Dart Rear Bumper.jpg 74 Valiant Rear Bumper.jpg
Front and rear bumpers on Chrysler A platform cars before (left, 1971) and after (right, 1974) the US 5-mph bumper standard took effect. The 1974 bumpers are larger, heavier, and mounted farther away from the body, and they no longer contain the taillamps.

In 1971, the US National Highway Traffic Safety Administration (NHTSA) issued the country's first regulation applicable to passenger car bumpers.[why?] Federal Motor Vehicle Safety Standard No. 215 (FMVSS 215), "Exterior Protection," took effect on 1 September 1972—when most automakers would begin producing their model year 1973 vehicles. The standard prohibited functional damage to specified safety-related components such as headlamps and fuel system components when the vehicle is subjected to barrier crash tests at 5 miles per hour (8 km/h) for front and 2.5 mph (4 km/h) for rear bumper systems.[14] The requirements effectively eliminated automobile bumpers designs that featured integral automotive lighting components such as tail lamps.

In October 1972, the US Congress enacted the Motor Vehicle Information and Cost Saving Act (MVICS), which required NHTSA to issue a bumper standard that yields the "maximum feasible reduction of cost to the public and to the consumer".[15] Factors considered included the costs and benefits of implementation, the standard's effect on insurance costs and legal fees, savings in consumer time and inconvenience, as well as health and safety considerations.

The 1973 model year passenger cars sold in the US used a variety designs. They ranged from non-dynamic versions with solid rubber guards, to "recoverable" designs with oil and nitrogen filled telescoping shock-absorbers.[16]

The standards were further increased for the 1974 model year passenger cars with standardized height front and rear bumpers that could take angle impacts at 5-mile-per-hour (8 km/h) with no damage to the car's lights, safety equipment, and engine. This often meant additional overall vehicle length, as well as new front and rear designs to incorporate the stronger energy absorbing bumpers.[17] Passenger cars featured gap-concealing flexible filler panels between the bumpers and the car's bodywork causing them to have a "massive, blockish look."[18] A notable exception that year was the new AMC Matador coupe that featured "free standing" bumpers with rubber gaiters alone to conceal the retractable shock absorbers.[18]

Regulatory effect on design[edit]

US (left) and rest-of-world (right)
1979 Mercedes 300SD 116.120.jpg Mercedes Benz W116 aka 280SE in Belgium.jpg
BMW-535is.jpg BMW 525i E28 01.jpg
Lamborghini Countach US spec 5000QV.jpg Lamborghini Countach (8014529631).jpg
Front bumpers on Mercedes-Benz W116 (top), BMW E28 5-series (middle), Lamborghini Countach (bottom): The US bumpers are more massive and protrude farther from the bodywork.

US Model cars were equipped with bulky, massive, heavy, protruding bumpers to to comply with the 5-mile-per-hour bumper standard imposed by NHTSA, in effect from 1973 to 1982. [19] Other models, such as the Citroën SM, were de facto banned by this regulation.

Strengthening standards[edit]

The requirements promulgated under MVICS were consolidated with the requirements of Federal Motor Vehicle Safety Standard Number 215 (FMVSS 215, "Exterior Protection of Vehicles") and promulgated in March 1976. This new bumper standard was placed in the United States Code of Federal Regulations at 49CFR581, separate from the Federal Motor Vehicle Safety Standards at 49CFR571. The new requirements, applicable to 1979-model year passenger cars, were called the Phase I standard. At the same time, a zero-damage requirement, Phase II, was enacted for bumper systems on 1980 and newer cars. The most rigorous requirements applied to 1980 through 1982 model vehicles; 5 miles per hour (8 km/h) front and rear barrier and pendulum crash tests were required, and no damage was allowed to the bumper beyond a 38 in (10 mm) dent and 34 in (19 mm) displacement from the bumper's original position.[20]

Freestanding 5-mph shock-absorbing zero-damage bumper, AMC Matador coupe

All-wheel-drive "cross-over" cars such as the AMC Eagle were classified as multi-purpose vehicle or trucks, and thus exempt from the passenger car bumper standards.[21]

Weakening standards[edit]

Facing pressure from automakers, and operating under the Reagan administration's pledge to reduce regulatory burdens on industry, NHTSA most recently amended the bumper standard in May 1982, halving the front and rear crash test speeds for 1983 and newer car bumpers from 5 miles per hour (8 km/h) to 2.5 miles per hour (4 km/h), and the corner crash test speeds from 3 miles per hour (5 km/h) to 1.5 miles per hour (2 km/h). In addition, the zero-damage Phase II requirement was rolled back to the damage allowances of Phase I. At the same time, a passenger car bumper height requirements of 16 to 20 inches (41–51 cm) was established for passenger cars.[20] At that time, NHTSA promised to conduct research and testing to provide consumers with accurate information on the quality of new car bumpers, but no such information has been provided.

Consumer and insurance groups have decried the weakened bumper standard, saying it has increased consumer costs without any attendant benefits except to automakers.[15][22][23][24]

In 1986, Consumers Union petitioned NHTSA to return to the Phase II standard and disclose bumper strength information to consumers. In 1990, NHTSA rejected that petition.[11]


Canada's bumper standard, first enacted at the same time as that of the United States, was generally similar to the US regulation. However, the Canadian standard was not weakened from 8 km/h (5 mph) to 4 km/h (2.5 mph) in accord with the weakened US standard of 1983. Some automakers chose to provide stronger Canadian-specification bumpers throughout the North American market, while others chose to provide weaker bumpers in the US market, which hampered private importation of vehicles from the US to Canada.

In early 2009, Canada's regulation shifted to harmonize with US Federal standards and international ECE regulations.[25] Consumer groups are upset with the change,[26] but Canadian regulators assert that the 4 km/h (2.5 mph) test speed is used worldwide and is more compatible with improved pedestrian protection in vehicle-pedestrian crashes.

International standards[edit]

European countries have implemented regulations to address the issue of 270,000 deaths annually in worldwide pedestrian/auto accidents. [27]

On the economic issue of repair costs, standards were developed under the international safety regulations were originally developed as European standards and now adopted by most countries outside North America. These specify that a car's safety systems must still function normally after a straight-on pendulum or moving-barrier impact of 4 km/h (2.5 mph) to the front and the rear, and to the front and rear corners of 2.5 km/h (1.6 mph) at 45.5 cm (18 in) above the ground with the vehicle loaded or unloaded.[28][29]

See also[edit]

Further Reading[edit]


  1. ^ Helps, Ian G. (2001). Plastics in European cars, 2000 - 2008. Shawbury RAPRA Technology. p. 99. ISBN 9781859572344. Retrieved 15 March 2014. 
  2. ^ "Bumpers". Insurance Institute for Highway Safety, Highway Loss Data Institute. Retrieved 15 March 2014. 
  3. ^ http://www.autonews.com/article/20120423/OEM03/304239967/european-safety-styled-cars-due-in-u.s.
  4. ^ http://www.sparebumper.com/index.php?act=viewProd&productId=48
  5. ^ "Gettiing Started". Underride Network. Underride Network. Retrieved 2014-06-07. 
  6. ^ "NHTSA bumper Q&A". Nhtsa.gov. Retrieved 6 January 2014. 
  7. ^ http://newsok.com/suv-fender-benders-can-lead-to-costly-repairs/article/feed/219283
  8. ^ http://www.roadandtrack.com/car-culture/a10353/incompatible-bumpers-raise-repair-costs/
  9. ^ http://www.iihs.org/iihs/ratings/bumpers?classType=Midsize%20moderately%20priced%20cars
  10. ^ http://articles.latimes.com/2002/jul/10/autos/hy-ouch10
  11. ^ a b "Consumer Bumper Quality Disclosure Bill". SmartMotorist.com. Retrieved 6 January 2014. 
  12. ^ http://papers.sae.org/2004-01-1610/
  13. ^ Elmarakbi, Ahmed (2014). Advanced composite materials for automotive applications : structural integrity and crashworthiness. Wiley. p. 130. ISBN 9781118535271. Retrieved 15 March 2014. 
  14. ^ La Heist, Warren G.; Ephraim, Frank G. "An Evaluation of the Bumper Standard - As Modified in 1982 - NHTSA Report Number DOT HS 807 072". Webcitation.org. Retrieved 6 January 2014. 
  15. ^ a b Congressional Record—Extension of Remarks[dead link] PDF (20.1 KB)
  16. ^ Lamm, Michael (October 1972). "AMC: Hornet hatchback leads the lineup". Popular Mechanics 138 (4): 118–202. Retrieved 6 January 2014. 
  17. ^ Norbye, Jan P. (October 1973). "New bumpers have uniform height, take angle impacts". Popular Science 203 (4): 90–91. Retrieved 6 January 2014. 
  18. ^ a b Cranswick, Marc (2011). The Cars of American Motors: An Illustrated History. McFarland. p. 209. ISBN 978-0-7864-4672-8. Retrieved 6 January 2014. 
  19. ^ James M. Flammang and the auto editors of Consumer Guide (2000). Cars of the Sensational '70s: A Decade of Changing Tastes and New Directions. Publications International. ISBN 0-7853-2980-3. 
  20. ^ a b "NHTSA Report DOT HS 807 072". Nhtsa.dot.gov. Retrieved 2010-08-21. [dead link]
  21. ^ Insurance Facts. Insurance Information Institute. 1980. p. 61. Retrieved 6 January 2014. 
  22. ^ IIHS Highway Loss Reduction Status Report - 6 October 1981 PDF (2.49 MB)
  23. ^ IIHS Highway Loss Reduction Status Report - 24 May 1982 PDF (939 KB)
  24. ^ Jensen, Cheryl (21 November 1999). "New York Times: Bumpers Cave In to the Bump and Grind". Nytimes.com. Retrieved 6 January 2014. 
  25. ^ "Canada to harmonize bumper standard with U.S., Europe". Autos Canada. 2 April 2008. Retrieved 6 January 2014. 
  26. ^ "Canada Safety Council: Canada Loosens Bumper Standard To Ali gn With U.S.". Safety-council.org. Retrieved 6 January 2014. 
  27. ^ http://www.autonews.com/article/20120423/OEM03/304239967/european-safety-styled-cars-due-in-u.s.
  28. ^ "United Nations ECE Regulation No. 42: Uniform Provisions Concerning the Approval of Vehicles With Regard to Their Front and Rear Protective Devices (Bumpers, etc.)" (PDF). 1 June 1980. Retrieved 6 January 2014. 
  29. ^ "NHTSA bumper Q&A". Nhtsa.gov. Retrieved 6 January 2014.