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The green-colored Automotive Digital Witness transmits the records of movement of the automobile to a computer, where its behavior can be observed through graphic animation. - Photo: Víctor Manuel Holguín/Unimedios

The Black Box: from Aircraft to Automobiles

May. 10 de 2012

By: Hermann Sáenz, Unimedios

Physicists have designed a device for automobiles to make it possible with a high degree of reliability to determine what occurs in a traffic accident and thus facilitate judicial proceedings. A black box, but for automobiles.

After an air accident, part of the work of first responders is to find the aircraft's black box where the flight parameters and conversations of the crew during an emergency are recorded. The compilation of those data makes it possible to reconstruct what happened before the accident and to determine its causes.

Inspired by this idea, Plinio Teherán, Professor of Physics at the Universidad Nacional de Colombia (National University of Colombia), created an apparatus based on the same principle, but to establish what has happened before, during and after a traffic accident. It is called the Testigo Digital Automotor (Digital Automotive Witness) (TDA) and, in contrast to the black box on an aircraft, it does not record conversations but merely records the dynamics of the movement of a vehicle as it travels.

The professor has been working for the last 15 years as a consultant for the Attorney General's Office to try to clarify the facts in vehicular collisions, and has observed that the mathematical patterns used for this purpose obtain reliable results in very few cases. “We carry out this work without being paid, at the request of the judicial institutions. It requires a lot of time and a sufficiently high technological level in order to obtain better and timely data”, adds Teherán.

That is why, along with two Physics and Engineering students, he built the TDA, as it is called, to reliably save the information, so that the trajectory, in other words the way in which an automobile moves, can be reconstructed.

The apparatus consists of accelerometers, memories and circuits, and is able to measure when an automobile backs up, turns to the right or left, goes over a bridge or reduces speed, etc. Because it is digital, its data is then processed in a computer, where an emulator then creates an animated version of the vehicle’s last movements.

Increased accidents

According to statistics kept by the Road Prevention Fund (Fondo de Prevención Vial), there are around 5,000 deaths each year in Colombia due to traffic accidents. “In 2000 there was a peak of 7,000 highway deaths. As a result of campaigns to promote the use of seat belts, the figure fell to 4,200, but motorcycle accidents have once again led to an increase”, comments Teherán.

Injuries due to traffic accidents have reached 50,000 per year. Data on how many of these people die after being hospitalized is not yet available because death certificates always give a different cause of death, such as cardiorespiratory failure.

The Colombian Insurers’ Federation (Federación de Aseguradores Colombianos Fasecolda) in 2010 recorded around 250,000 accidents involving vehicular damage but without injuries, and in the great majority of such cases the guilty party is never determined. “It appears that drivers do not care if they break the law because they feel sure that they will never be prosecuted. Given that lack of concern, along with the inability of the system to prosecute the responsible parties, it is only natural that there is an increase in the number of accidents”, explains the physicist.

That is why the idea is to convert the TDA into a forensic tool, so that responsibility can be determined and cases can be promptly and fairly resolved. This system is actually an improved version of Wii, which uses accelerometers. “When the racket moves, the computer records it because the accelerometer indicates the angle that is activating the device. The accelerometers in the game consoles are of lesser quality than the ones we use, because Wii is not able to deal with an increase in velocity on the order of 300 g (gravities), which is what happens when an automobile collides with a truck”, according to Yamid Núñez, a Masters student in Physics at the UN and a member of the project.

The TDA, whose size is similar to that of a cellular phone, has been subjected to processes of acceleration and tested in different parts of vehicles and even motorcycles, where it has been shown to record every movement. The apparatus is installed near the gearshift lever underneath the radio, a zone rarely affected by the deformation following a serious collision. At the same time, the device would be enclosed in a steel box that only a competent authority would be permitted to open in order to recover the information.

The apparatus would be capable of recording as many as 10,000 pieces of data per second, which is enough to reconstruct what happens during a collision. The necessary information, with certain algorithms, is permanently recorded in an inviolable memory. “We are working to provide the apparatus with a sufficient degree of invulnerability, so that the data could not be altered mechanically, electrically, or by hackers”, says Teherán.

One of the big advantages of this device in the court system is that it would make it possible to resolve cases in less time. Currently, with the new accusatory criminal system, two years or more can pass between the time when an accident occurs and when formal charges are brought. The TDA provides virtual animation of the accident in five minutes and would therefore substantially reduce the timeframe for trial.

In addition to being convinced of the valuable contribution of the TDA in clarifying what has happened during a traffic accident, Teherán and his students are sure that, if each driver were to have one of these apparatus installed in their vehicle, they would think twice before committing imprudent acts. They therefore look to the possibility that someday pedestrians would carry a similar but smaller device on their belts to be able to completely clarify any accident that they could suffer.

“We designed and presented the proposal, and now we are working to get it accepted”, concluded the physicist from the Universidad Nacional.