The accident data recorder (ADR, German commonly abbr.: UDS, also accident (data) writer), is an independent electronic device that records before, during, and after a traffic accident relevant data and thus resembles a

flight recorder A flight recorder is an electronic recording device placed in an aircraft for the purpose of facilitating the investigation of aviation accidents and incidents. The device may often be referred to as a "black box", an outdated name which has b ...

. It can be installed in motor vehicles (

cars A car or automobile is a motor vehicle with wheels. Most definitions of ''cars'' say that they run primarily on roads, seat one to eight people, have four wheels, and mainly transport people instead of goods. The year 1886 is regarded as t ...

trucks A truck or lorry is a motor vehicle designed to transport cargo, carry specialized payloads, or perform other utilitarian work. Trucks vary greatly in size, power, and configuration, but the vast majority feature body-on-frame construction ...

buses A bus (contracted from omnibus, with variants multibus, motorbus, autobus, etc.) is a road vehicle that carries significantly more passengers than an average car or van. It is most commonly used in public transport, but is also in use for cha ...

motorcycles A motorcycle (motorbike, bike, or trike (if three-wheeled)) is a two or three-wheeled motor vehicle steered by a handlebar. Motorcycle design varies greatly to suit a range of different purposes: long-distance travel, commuting, cruising, ...

trams A tram (called a streetcar or trolley in North America) is a rail vehicle that travels on tramway tracks on public urban streets; some include segments on segregated right-of-way. The tramlines or networks operated as public transport are ...

, and special vehicles) on a voluntary basis in order to obtain more accurate information about the events in an

accident An accident is an unintended, normally unwanted event that was not directly caused by humans. The term ''accident'' implies that nobody should be blamed, but the event may have been caused by unrecognized or unaddressed risks. Most researcher ...

. In some countries there are regulations for mandatory installation in different vehicles. The accident data recorder constantly records various data of the vehicle (such as

speed In everyday use and in kinematics, the speed (commonly referred to as ''v'') of an object is the magnitude of the change of its position over time or the magnitude of the change of its position per unit of time; it is thus a scalar quanti ...

, direction of travel, longitudinal and transverse vehicle acceleration, status of the lights, turn signals and braking, etc.) and records them for some time before they are automatically cleared. In the case of an accident (this is detected by a strong

acceleration In mechanics, acceleration is the rate of change of the velocity of an object with respect to time. Accelerations are vector quantities (in that they have magnitude and direction). The orientation of an object's acceleration is given by the ...

of the vehicle as a result of an impulse), certain periods of time (usually in the two-digit seconds range) remain permanently stored before and after an event. This makes it much easier to reconstruct events after an accident, so that if necessary the question of fault can be clarified. Many vehicles of authorities (such as

police The police are a constituted body of persons empowered by a state, with the aim to enforce the law, to ensure the safety, health and possessions of citizens, and to prevent crime and civil disorder. Their lawful powers include arrest and t ...

ambulance An ambulance is a medically equipped vehicle which transports patients to treatment facilities, such as hospitals. Typically, out-of-hospital medical care is provided to the patient during the transport. Ambulances are used to respond to medi ...

) are equipped with it, as it often comes to disputes with collisions during driving with blues and twos about compliance with regulations. A side effect of vehicles equipped with UDS is that drivers behave more cautiously on the road. According to a survey by the EU Transport Commission, UDS users experienced a 20 to 30 percent decline in traffic accidents. The accident data recorder is often used by

experts An expert is somebody who has a broad and deep understanding and competence in terms of knowledge, skill and experience through practice and education in a particular field. Informally, an expert is someone widely recognized as a reliable so ...

or institutions in

crash tests A crash test is a form of destructive testing usually performed in order to ensure safe design standards in crashworthiness and crash compatibility for various modes of transportation (see automobile safety) or related systems and componen ...

as a measuring device. UDS-AT

The installation (also later) costs about 700 euros and can lead to a deduction for some

insurance policies In insurance, the insurance policy is a contract (generally a standard form contract) between the insurer and the policyholder, which determines the claims which the insurer is legally required to pay. In exchange for an initial payment, known as ...

. The accident data recorder can be read by an expert via interface cable. The accident data recorder (older generations) has a switch with which the driver can delete the stored data immediately after an accident so as not to burden himself with the later question of guilt. However, this feature may be disabled, for example for use in company vehicles.

Technology

Accident data recorders work to measure the accelerations, depending on the equipment in two or three spatial directions, with micromechanical sensors. Often several sensor systems with different resolutions are used in order to be able to log the driving dynamic processes on the one hand and the collision dynamics themselves on the other. Higher-class systems also offer a possibility for measuring the rotational movements as well as the vehicle speed. The latter can e.g. be calculated from the signal of the vehicle's

wheel speed sensor A wheel speed sensor (WSS) or vehicle speed sensor (VSS) is a type of tachometer. It is a sender device used for reading the speed of a vehicle's wheel rotation. It usually consists of a toothed ring and pickup. Automotive wheel speed sensor ...

. The recording of any signals that are available on the vehicle's own

CAN bus A Controller Area Network (CAN bus) is a robust vehicle bus standard designed to allow microcontrollers and devices to communicate with each other's applications without a host computer. It is a message-based protocol, designed originally for mu ...

, is possible with higher-class devices as well as the detection of a

GPS The Global Positioning System (GPS), originally Navstar GPS, is a Radionavigation-satellite service, satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of t ...

signal for position and speed determination. Depending on the manufacturer, about 20 to 30 s are recorded before and 10 to 15 s after an event. Are known today (as of 2018) in the German-speaking countries essentially two suitable for retrofitting accident data recorder. Blacktrack Ltd. offers a low-cost solution, which is mainly used by the insurance industry (e.g.

AXA Axa S.A. (styled as ''AXA'' or GIG in the Middle East) is a French multinational insurance company. The head office is in the 8th arrondissement of Paris, France. It also provides investment management and other financial services. The Ax ...

Winterthur in Switzerland). By contrast, the UDS-AT developed by the company consortium Peter Systemtechnik GmbH and Kast GmbH offers extended possibilities of recording and integration into a vehicle. Residual path recording devices (RAG) from Mobatime AG are external devices that rely on existing on-board signals (distance, speed, operating states of status inputs) and store them in a ring buffer for at least the last 12 km. In contrast to an accident data recorder, they do not have their own measuring sensors.

Evaluation

Reading out the data of an accident data recorder requires special software. The evaluation and interpretation of measurement data of a traffic accident require special knowledge in the areas of

vehicle dynamics For motorized vehicles, such as automobiles, aircraft, and watercraft, vehicle dynamics is the study of vehicle motion, e.g., how a vehicle's forward movement changes in response to driver inputs, propulsion system outputs, ambient conditions, air ...

accident reconstruction Traffic collision reconstruction is the process of investigating, analyzing, and drawing conclusions about the causes and events during a vehicle collision. Reconstructionists conduct collision analysis and reconstruction to identify the cause ...

metrology Metrology is the scientific study of measurement. It establishes a common understanding of units, crucial in linking human activities. Modern metrology has its roots in the French Revolution's political motivation to standardise units in Fran ...

and last but not least the accident data storage technology itself. For UDS there is a separate order area for expert witnesses in Germany. The picture on the right shows the (unprocessed) data curves of a real accident recorded with a UDS. The measured accelerations, the speed and various status channels are plotted over time. It can be seen, for example, that vehicle special signals were switched on prior to the collision and the driver was previously still applying the brake.

History

The nowadays known accident data recorder was invented by Mannesmann Kienzle GmbH, which applied for a patent in 1992. The development began in Germany in the early 1980s with the two companies MBB and Kienzle, who pursued different concepts. In general, the black box was taken as a model, which was developed in the early 1950s in Australia by David Warren. Already in 1973, General Motors applied for a patent for a "vehicle crash recorder". Mannesmann Kienzle delivered the first accident data recorder in early 1993.

Motorsport

motorsport Motorsport, motorsports or motor sport is a global term used to encompass the group of competitive sporting events which primarily involve the use of motorized vehicles. The terminology can also be used to describe forms of competition of two ...

, accident data recorders (ADR) must be used in various series as specified by the

FIA FIA is the Fédération Internationale de l'Automobile (English: International Automobile Federation), the world's governing body for all forms of motor sport where four or more wheels are used. Fia or FIA may also refer to: People * Fia Backst ...

. Starting with the 2015 season, the use of an ADR in the

Formula 4 FIA Formula 4, also called FIA F4, is an open-wheel racing car category intended for junior drivers. There is no global championship, but rather individual nations or regions can host their own championships in compliance with a universal set of r ...

championship was compulsory. In the higher series, the use has been mandatory for some time. In addition to the data of the acceleration sensors mounted on the vehicle, the loads on the driver are also measured with an in-ear accelerometer. Due to the higher speeds in formula sports compared to road traffic, the sensors have a measuring range of ± 150 g with a resolution of 0.1 g. 2 s are recorded before an event. With an event duration of 30 s, 10 events can be stored.

Demarcation

Both in a

and in a UDS, the constantly recorded data runs in a

ring buffer In computer science, a circular buffer, circular queue, cyclic buffer or ring buffer is a data structure that uses a single, fixed-size buffer as if it were connected end-to-end. This structure lends itself easily to buffering data streams. Ther ...

. However, the flight recorder usually records for longer periods of 17 to 25 hours. In contrast, the UDS only saves a few seconds before and after an event is triggered (e.g. collision) permanently. The term ''drive data recorder'' is generally understood to mean a continuous and permanently available recording of data and signals during the operation of a vehicle, independently of an accident. Such systems are often used in locomotives or trams. Often, however, an

electronic logbook A logbook (or log book) is a record used to record states, events, or conditions applicable to complex machines or the personnel who operate them. Logbooks are commonly associated with the operation of aircraft, nuclear plants, particle accelera ...

is referred to as drive data recorder.

Dashcam A dashboard camera or simply dashcam, also known as car digital video recorder (car DVR), driving recorder, or event data recorder (EDR), is an onboard camera that continuously records the view through a vehicle's front windscreen and sometimes ...

s are sometimes referred to as drive data recorder or ''video event data recorder'' (VEDR). A so-called ''Event Data Recorder'' (EDR) is not an accident data recorder in the sense of an autonomous, more or less vehicle-independent device, since an EDR is usually an additional electronic module in an existing control device (e.g. from the

Airbag An airbag is a vehicle occupant-restraint system using a bag designed to inflate extremely quickly, then quickly deflate during a collision. It consists of the airbag cushion, a flexible fabric bag, an inflation module, and an impact sensor. Th ...

) in a car. EDRs rely exclusively on on-board signals, while UDS have their own inertial sensors. Vehicles with airbag systems store accident-relevant data (impact accelerations, belt buckle conditions, seat positions, trip times) in the internal memory of the tripping electronics. However, the data size varies depending on the manufacturer and only extends over a few seconds or fractions.

NHTSA The National Highway Traffic Safety Administration (NHTSA ) is an agency of the U.S. federal government, part of the Department of Transportation. It describes its mission as "Save lives, prevent injuries, reduce vehicle-related crashes" relat ...

regulations call for uniform data sets for all systems manufactured from 2010 onwards.

References

External links

Vehicle Event Recording based ON Intelligent Crash Assessment
EU project between 2004 and 2009 on accident data storage * {{cite web , url=https://ec.europa.eu/transport/sites/transport/files/docs/study_edr_2014.pdf , title=Study on the benefits resulting from the installation of Event Data Recorders , publisher=

Transport Research Laboratory TRL Limited, trading as TRL (formerly Transport Research Laboratory) is an independent private company offering a transport consultancy and research service to the public and private sector. Originally established in 1933 by the UK Government a ...

, date=2014 Automotive electronics Recording devices Transport accidents and incidents Vehicle technology