 | This articleneeds additional citations forverification. Please helpimprove this article byadding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Dashcam" – news ·newspapers ·books ·scholar ·JSTOR(November 2023) (Learn how and when to remove this message) |
Adashboardcamera or simplydashcam, also known ascardigital video recorder (car DVR),driving recorder, orevent data recorder (EDR), is anonboard camera thatcontinuously records the view through a vehicle's front windscreen and sometimes rear or other windows. Some dashcams include a camera to record the interior of the car in 360 degrees inside camera, usually in a ball form, and can automatically send pictures and video using 4G.
EDRs and some dashcams also record acceleration/deceleration g-force, speed, steering angle,GPS data, voltage of the power source (vehicle's electrical net), etc.
Awide-angle 130, 170° or more front camera may be attached to the interior windscreen, to therear-view mirror (clip on), or to the top of thedashboard, bysuction cup or adhesive-tape mount. A rear camera is usually mounted in the rear window or in theregistration plate, with anRCA video output to the display monitor/screen.
The resolution will determine the overall quality of the video. FullHD or 1080p (1920×1080) is standard for dash HD cams. Dash cameras may have1080p, 1296p (common for Chinese dashcams),1440p, or higher definition for a front camera and720p for a back camera and includef/1.8aperture andnight vision mode.
By targeted field of view:
Some cabin cams include a screen that can be attached to therear-view mirror employing usuallyrubber rings orstraps or as a direct replacement of the rear view mirror itself. Others attach to the windshield, dash, or other suitable interior surfaces
Many dashcams includerechargeable batteries not needed when connected to car battery wire orcapacitors.
To ensure that recorded video files are not tampered with once they have been recorded, videos can be timestamped in a tamper-proof manner, a procedure termedtrusted timestamping.
To ensure a reliable24/7 parkingsurveillance when capacity is an issue, amotion detector may be used to record only when an approaching human/vehicle is detected, in order to save power and storage media.[1]
Advanced driver assistance system ADAS and park location save can be included.
Dashcams usually use class 10 or aboveMicroSDHC or MicroSDXC cards usually 16 GB or higher or internal memory to save videos.
The port to connect the GPS antenna can use a microUSB or3.5 mm jack connection. The antenna is usually 1575 to 1568MHz and 3.0 to 5.0V.
GPS coordinate stamping capability is included in most dashcams (some need an external GPS antenna, but other dashcam systems have built-in GPS), and others include GPS (online and offline) navigation.
Some dashcams includeWi-Fi,Bluetooth, and4G connectivity.
For Bluetooth and voice commands and recording, a built-inmicrophone is included.
4G triple-cam (also called triple-lens and three-way-cams) sets onrearview mirror are becoming more available (2 front cameras - one 170° to mainly record road, one 360° for sides and doors and a rear camera).
4G is used to send messages, calls, pictures, and videos in parking surveillance mode. Usually a second 360° camera is employed to record the car's sides front doors and windows and inside.
Also, 4G is used to send a message when the car battery is low.
Dashcam units usually operate via the vehicle electrical system, converting the 13.8V to a 5V USB connector. Dashcams can be plugged in via thecigarette lighter socket, or may be hardwired directly into the electrical system, freeing up the power outlet for other uses.
In order to store files and properly format the media card when power is turned off, dashcams use either a Lithium Polymer (LiPo) battery or a capacitor. While both provide power for a very short period of time, they have very different operating capabilities and limitations. LiPo batteries have an estimated life of 2-3 years or roughly 300-500 cycles. Over time, the material inside the battery will start to degrade resulting in out-gassing. This can be observed in a swollen or puffy looking battery case. When a LiPo battery reaches this point, the battery is no longer able to hold a charge. The result is a camera that may randomly turn on or off, or register format errors if it can't shut down correctly when power is turned off since it can only function when using the power from the vehicle. Capacitors can also store a temporary charge and will last much longer. They are also more resistant to higher operating temperatures, but are more expensive and require additional hardware or software support. Generally the LiPo batteries are found in less expensive dashcams and capacitors are used in more expensive dashcams.
Dashcams are widespread inRussia[2] as a guard againstpolice corruption andinsurance fraud, where they provide additional evidence.[3] They have been called "ubiquitous" and "an on-line obsession", and are so prevalent that dashcam recordings were the most common videos of the February 2013Chelyabinsk meteor,[4] which was documented from at least a dozen angles. Videos showing automobile and aircraft crashes, close calls, and attempts at insurance fraud have been uploaded to social sharing websites such asYouTube,Facebook,Twitter,Yandex, and other websites.[citation needed]
In the United Kingdom, sales of dashcams rocketed in 2015, which was the fastest growing consumer electronic, with sales increasing by 395%.[5]
In China, dashcams were well-known by a dramatic event of a road rage.[6][further explanation needed]
Dashcams have also captured numerous aviation accidents, such asNational Airlines Flight 102 in 2013,[7]TransAsia Airways Flight 235 in 2015,[8] theShoreham Airshow crash in 2015.[9] and the catastrophic engine failure ofUnited Airlines Flight 328 in 2021.[10]
Dashboard cameras have become the top feature wanted by future vehicle buyers,[11] and more car manufacturers are incorporating built-in camera systems.[12]
While dashcams are gaining in popularity as a way of protection against distortion of facts, they also attract negative attitudes for privacy concerns. This is also reflected in the laws of different countries in different and conflicting ways:
Police departments use dashcams in police vehicles to gather evidence duringtraffic stops andcar chases.[23] Some dashcam systems can be automatically activated when a police car'semergency lights or siren are turned on.[24][25][26]Freedom of information laws mean that the footage can be released under some circumstances,[27] and this can be an important tool in reporting on police actions.[28] TV shows likeWorld's Wildest Police Videos have frequently featured car chase videos shot from dashcams.
Some police officers accused ofpolice brutality ormisconduct tamper with their cameras to disable audio or video recording.[29] A report in 2016 showed that in Chicago, 80% of the police dashcams did not work properly. Among the causes were that officers destroyed antennas, hid microphones, and removed batteries or recording media.[30]
