page_title: Bumper (car)
section_title: Height mismatches
hierarchical_section_title: Bumper (car) / Height mismatches
caption_attribution_description: Deutsch: A 99 Unfall - Mercedes an der Leitplanke mit eingedrückter Schnauze. Schleuderspuren auf der Fahrbahn.
context_page_description: A bumper is a structure attached to or integrated with the front and rear ends of a motor vehicle, to absorb impact in a minor collision, ideally minimizing repair costs. Stiff metal bumpers appeared on automobiles as early as 1904 that had a mainly ornamental function. Numerous developments, improvements in materials and technologies, as well as greater focus on functionality for protecting vehicle components and improving safety have changed bumpers over the years. Bumpers ideally minimize height mismatches between vehicles and protect pedestrians from injury. Regulatory measures have been enacted to reduce vehicle repair costs and, more recently, impact on pedestrians.
context_section_description: For passenger cars, the height and placement of bumpers is legally specified under both US and EU regulations. Bumpers do not protect against moderate speed collisions, because during emergency braking, suspension changes the pitch of each vehicle, so bumpers can bypass each other when the vehicles collide. Preventing override and underride can be accomplished by extremely tall bumper surfaces.  Active suspension is another solution to keeping the vehicle level. 
  Bumper height from the roadway surface is important in engaging other protective systems. Airbag deployment sensors typically do not trigger until contact with an obstruction, and it is important that front bumpers be the first parts of a vehicle to make contact in the event of a frontal collision, to leave sufficient time to inflate the protective cushions. 
  Energy-absorbing crush zones are completely ineffective if they are physically bypassed; an extreme example of this occurs when the elevated platform of a tractor-trailer completely misses the front bumper of a passenger car, and first contact is with the glass windshield of the passenger compartment.
caption: Damage from a low-speed but high-level impact; the energy-absorbing front bumper system is completely bypassed and untouched.
exif: {"Image Make": "Canon", "Image Model": "Canon EOS 1000D", "Image Orientation": "Horizontal (normal)", "Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "ACD Systems Digital Imaging", "Image DateTime": "2011:05:29 15:50:42", "Image Artist": "Max B.", "Image YCbCrPositioning": "Centered", "Image ExifOffset": "239", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail JPEGInterchangeFormat": "9609", "Thumbnail JPEGInterchangeFormatLength": "8272", "EXIF ExposureTime": "1/160", "EXIF FNumber": "16", "EXIF ExposureProgram": "Shutter Priority", "EXIF ISOSpeedRatings": "200", "EXIF ExifVersion": "0221", "EXIF DateTimeOriginal": "2011:05:29 13:28:55", "EXIF DateTimeDigitized": "2011:05:29 13:28:55", "EXIF ComponentsConfiguration": "Y", "EXIF ShutterSpeedValue": "59/8", "EXIF ApertureValue": "8", "EXIF ExposureBiasValue": "0", "EXIF MeteringMode": "CenterWeightedAverage", "EXIF Flash": "Flash did not fire, compulsory flash mode", "EXIF FocalLength": "105", "EXIF SubSecTime": "734", "EXIF SubSecTimeOriginal": "38", "EXIF SubSecTimeDigitized": "38", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "2103", "EXIF ExifImageLength": "1413", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "EXIF InteroperabilityOffset": "9521", "EXIF FocalPlaneXResolution": "704000/219", "EXIF FocalPlaneYResolution": "1880000/583", "EXIF FocalPlaneResolutionUnit": "2", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF SceneCaptureType": "Standard"}