Road Accident Analysis (RAA)
Since its establishment, CFIIV “Ivan Vučetić” has carried out various forms of Road Accident Analysis (RAA).
Initially, this included the examination of glass and plastic traces and other vehicle parts found at an accident scene in order to determine to which vehicle (make and/or model) they belonged. Shortly after, two new methods were introduced in the Centre - the method of examining light-bulb filaments to determine whether a particular light on a vehicle was on or off at the moment of the accident, and the tyre-examination method used to determine whether tyre failure was the cause or the consequence of a road traffic accident.
In the 1970s, the Centre began researching and analysing vehicle braking and steering systems to determine whether a fault in one of these systems components was the cause of a traffic accident. Soon after, methods for examining Road Accident Dynamics with time-way analysis began to be applied in the Centre.
In addition to developing and implementing new forensic methods, experts in the field of RAA participate in the training of police officers and provide professional assistance during on-site investigations of serious traffic accidents.
Over the years, due to the increasing number of vehicles and the expanding road network, as well as the increasing daily business and tourism-related mobility of the population, the scope of RAA work has grown significantly
Nowadays, RAA expertise in the Centre includes:
Examinations and analyses are carried out within the following methods:
PC-Crash
Significant progress in RAA was achieved through the introduction of the PC-Crash simulation software. The software was introduced in 2002 and has been in everyday use since then.
PC-Crash is modular software for the simulation of real collision processes, analysing individual accident parameters, and using advanced modules that include GNSS data, video analysis, and other data sources to obtain additional information related to a crash event.
CDR (Crash Data Retrieval) Device
In 2023, the Centre acquired the Bosch CDR 900 system for extracting and interpreting Event Data Recorder (EDR) data - the vehicle’s “black box”.
The Bosch CDR tool covers over 88% of vehicles from model year 2016 onward (EU market), with coverage increasing as new models appear. This tool consists of hardware, which, in addition to the CDR interface for connecting to the vehicle, also includes connecting cables and adapters for direct access to the modules and software designed to work in a Windows environment.
Depending on the vehicle make, model, and year, the Bosch CDR/EDR tool can read up to 41 different data parameters from the airbag module of a crashed vehicle (e.g., vehicle speed at and up to approx. 5 seconds before impact, deceleration, delta-V, steering-wheel angle, seatbelt activation, and other relevant data), which are crucial for accident analysis.
Road-Surface Measurement Devices
a) Friction-Coefficient Meter
As in other forensic fields, the Centre continuously monitors technological developments and acquires equipment that increases the quality and accuracy of accident-parameter determination, such as vehicle speed, travel distance, and reaction time.
One of the key devices is the T2GO friction-measurement system. Although literature provides indicative friction-coefficient values depending on road surface and tyre condition, only direct on-site measurement can determine the exact value and thus allow precise calculation of pre-braking speed. The device measures selected road segments and automatically uploads values to a portable computer for further analysis.
b) Road-Surface Roughness Meter
The Centre also uses the Roughmeter III, for road-surface-condition analysis. The device should be mounted on a vehicle and collects data during driving using GPS, storing it in the control unit. The obtained data - road quality according to specific standards, critical points, and road-surface parameters - is analysed to determine possible causal links between road conditions and traffic accidents.
It is also important to mention that the Center's RAA experts are members of international associations such as the European Association for Accident Research and Analysis (EVU) and the ENFSI Traffic Expertise Working Group (RAAEWG), in whose work they actively participate.
Initially, this included the examination of glass and plastic traces and other vehicle parts found at an accident scene in order to determine to which vehicle (make and/or model) they belonged. Shortly after, two new methods were introduced in the Centre - the method of examining light-bulb filaments to determine whether a particular light on a vehicle was on or off at the moment of the accident, and the tyre-examination method used to determine whether tyre failure was the cause or the consequence of a road traffic accident.
In the 1970s, the Centre began researching and analysing vehicle braking and steering systems to determine whether a fault in one of these systems components was the cause of a traffic accident. Soon after, methods for examining Road Accident Dynamics with time-way analysis began to be applied in the Centre.
In addition to developing and implementing new forensic methods, experts in the field of RAA participate in the training of police officers and provide professional assistance during on-site investigations of serious traffic accidents.
Over the years, due to the increasing number of vehicles and the expanding road network, as well as the increasing daily business and tourism-related mobility of the population, the scope of RAA work has grown significantly
Nowadays, RAA expertise in the Centre includes:
- Reconstruction of traffic accidents at the scene.
- Determining accident dynamics, vehicle speed before, during, and after the accident; determining collision positions; and time-way accident analysis.
- PC Crash accident simulations up to final vehicle positions according to police documentation, and analysis of pre-collision vehicle movement, driver reaction possibilities, and accident-avoidance possibilities.
- Determining the technical condition of active-safety systems in cases where there is significant suspicion that system malfunction may have caused an accident.
- Examination of light-bulb filaments to determine whether the filament was hot or cold at the time of the accident (i.e., whether the light was on or off).
- Examination of tyre marks when there is significant suspicion that the accident was caused by a tyre decompression.
Examinations and analyses are carried out within the following methods:
- RAA expertise with time-way analysis
- Light-bulbs with filament examination
- Wheel/tyre examination
- Determining the technical condition of vehicle active-safety elements
- Vehicle-part fragment fitting and vehicle identification
PC-Crash
Significant progress in RAA was achieved through the introduction of the PC-Crash simulation software. The software was introduced in 2002 and has been in everyday use since then.
PC-Crash is modular software for the simulation of real collision processes, analysing individual accident parameters, and using advanced modules that include GNSS data, video analysis, and other data sources to obtain additional information related to a crash event.
CDR (Crash Data Retrieval) Device
In 2023, the Centre acquired the Bosch CDR 900 system for extracting and interpreting Event Data Recorder (EDR) data - the vehicle’s “black box”.
The Bosch CDR tool covers over 88% of vehicles from model year 2016 onward (EU market), with coverage increasing as new models appear. This tool consists of hardware, which, in addition to the CDR interface for connecting to the vehicle, also includes connecting cables and adapters for direct access to the modules and software designed to work in a Windows environment.
Depending on the vehicle make, model, and year, the Bosch CDR/EDR tool can read up to 41 different data parameters from the airbag module of a crashed vehicle (e.g., vehicle speed at and up to approx. 5 seconds before impact, deceleration, delta-V, steering-wheel angle, seatbelt activation, and other relevant data), which are crucial for accident analysis.
Road-Surface Measurement Devices
a) Friction-Coefficient Meter
As in other forensic fields, the Centre continuously monitors technological developments and acquires equipment that increases the quality and accuracy of accident-parameter determination, such as vehicle speed, travel distance, and reaction time.
One of the key devices is the T2GO friction-measurement system. Although literature provides indicative friction-coefficient values depending on road surface and tyre condition, only direct on-site measurement can determine the exact value and thus allow precise calculation of pre-braking speed. The device measures selected road segments and automatically uploads values to a portable computer for further analysis.
b) Road-Surface Roughness Meter
The Centre also uses the Roughmeter III, for road-surface-condition analysis. The device should be mounted on a vehicle and collects data during driving using GPS, storing it in the control unit. The obtained data - road quality according to specific standards, critical points, and road-surface parameters - is analysed to determine possible causal links between road conditions and traffic accidents.
It is also important to mention that the Center's RAA experts are members of international associations such as the European Association for Accident Research and Analysis (EVU) and the ENFSI Traffic Expertise Working Group (RAAEWG), in whose work they actively participate.