Vector model of vehicle collisions for inferring velocity from loss of kinetic energy with restitution on residual crush surface

In the standard mathematical model that underpins the inference of velocity change from vehicle damage in road accident reconstruction, the point where the colliding bodies engage is taken to lie in the same location as the point of application of the average impact force, usually in the central region of the crush zone or on the residual crush surface. Mathematical and physical reasons suggest the fidelity of the model could be deepened by allowing for a separation of these points, for example by locating the impulse or average force in the central region of the crush zone and defining engagement (common velocity or rebound) relative to the crush surface. Refinement of the theory revealed that the solutions for the change of linear and angular velocity are unaffected. For long-running in-depth research studies, this means that historical calculations of velocity change (delta-V) and related analyses on such topics as injury risk curves, countermeasure effectiveness and accident scenarios are not potentially undermined. Relative and absolute velocity are however affected. This was illustrated using crash test data where adjustments of six and twelve centimetres resulted in changes of up to four percent in road speed

Interaction of road environment, vehicle and human factors in the causation of pedestrian accidents

The UK On-the-Spot project (OTS) completed over 1500 in-depth investigations of road accidents during 2000-2003 and is continuing for a further 3 years. Cases were sampled from two regions of England using rotating shifts to cover all days of the week and all hours of the day and night. Research teams were dispatched to accidents notified to police during the shifts; arrival time to the scene of the accident was generally less than 20 minutes. The methodology of OTS includes sophisticated systems for describing accident causation and the interaction of road, vehicle and human factors. The purpose of this paper is to describe and illustrate these systems by reference to pedestrian accidents. This type of analysis is intended to provide an insight into how and why pedestrian accidents occur in order to assist the development of effective road, vehicle and behavioural countermeasures

A comparison of injury risk and pattern of injury for male and female occupants of moden European passenger cars

Accident injury data from the UK Cooperative Crash Injury Study (CCIS) was examined for differences between men and women in accident circumstances and injury outcomes. The CCIS database from 1992 to 2000 contains "in-depth" information on almost 14000 car occupants from real road accidents. Although females constitute only around 40% of the sample, they outnumber males in the passenger seats. This shows that women should not be neglected in the design of vehicle safety systems. Soft tissue neck injury (whiplash) is more common among women in all accident types, and there are other differences in the vulnerability to injury and the body region most likely to be injured in frontal, side and rear impacts. The tuning of advanced restraint systems and vehicle crumple zones may offer further potential benefits to women. Today’s vehicle safety community has inherited an emphasis on male characteristics in its knowledge base, research and testing programs, and regulations. Funding bodies should be aware of this and encourage a balanced consideration of female characteristics

Male and female car drivers - difference in collision and injury risks

Crash data from two UK resources were examined for differences between male and female passenger car drivers in collision circumstances and injury outcomes. The proportion of female car licence holders is growing, women are more likely to be the driver in a collision and are more vulnerable to injury particularly neck strain. Women drive smaller, lighter cars compared to men and are more often the driver of the smaller vehicle in a multivehicle collision. Vehicle design, crash testing programmes and regulation, currently based heavily on the average male, should give more balanced consideration to female characteristics in future activities

Use of smart technologies to collect and retain crash information

Task 1.1 of Pendant Work Package 1 has a threefold objective: firstly to develop methods and guidelines for the reconstruction of road traffic accidents, secondly to develop a database of information about public domain crash tests, and thirdly to develop methods for determining the comparability and accuracy of reconstruction methods. As part of the third aim the Description of work (2001) states: "Specific reference will be made to the use of smart technologies to collect and retain information about the crash (‘black boxes’, ‘crash recorders’). The Task will examine current capabilities and identify the main obstacles to their wider implementation." The purpose of this report is to provide an overview of the state of the art in recording information about the crash phase, including current capabilities and main obstacles to further implementation

The accuracy of CRASH3 for calculating collision severity in modern European cars

CRASH3 is a computer program that enables a vehicle's change of velocity during a crash to be deduced from the observed damage to the vehicle(s) involved. Along with other programs that share similar mathematical techniques, it is widely used internationally, particularly by groups and individuals who have access to damaged vehicles but not the accident scene, and it is applied to a wide range of vehicles and accident circumstances. Crash tests conducted under controlled conditions provide an opportunity to assess the program's accuracy. In this paper CRASH3 is applied to vehicles tested during 1996-98 in the first three phases of the EuroNCAP program. This includes results from 26 models tested in 64 km/h offset frontal impacts and 50 km/h side impacts. On average, velocity changes were underestimated by 1 km/h for the side test and 7 km/h for the frontal test–this includes the effect of a special treatment of deformable barriers not available in the standard program

The statistical accuracy of Delta-V in systematic field accident studies

Much attention has been paid to the importance of calculating delta-V (the change of velocity during impact) and other impact severity measures accurately. However delta-V cannot be evaluated in every case sampled by a systematic study of road accidents. This can lead to statistical distortions if the subsample of cases for which delta-V is calculated is not representative of the whole sample. This problem has received less recognition than the problem of calculating delta-V accurately when it is calculated. This paper contains new results on the accuracy of CRASH3 delta-V for European passenger cars and a discussion of the problem of calculating delta-V for a representative subsample. On the data available, CRASH3 underestimates delta-V for rigid and deformable barrier impacts but not frontal car-to-car impacts. The statistical results obtained using any single method for calculating delta-V are likely to be unrepresentative of certain classes of impact type, impact severity and collision partner. A flexible approach towards using a variety of methods to evaluate delta-V is necessary to counter this difficulty

The influence of European air bags on crash injury outcomes

The UK Co-operative Crash Injury Study currently includes data on 205 seat belted drivers from frontal impacts in which an air bag deployed; of these, 142 suffered some degree of injury. To detect the influence of frontal air bags, the distribution of injury over the body regions of these drivers was compared to that of a much larger group from vehicles without air bags. The injured drivers from air bag vehicles showed relatively fewer head injuries, especially fractures, and relatively more arm injuries. No abnormal types of injury or circumstances of injury were identified for the air bag group. Air bags generally appear to deploy at vehicle impact severities that pose a statistical risk of significant head injury, and also in a proportion of lower severity impacts. As a group, the air bag equipped vehicles were larger, more modern, and more often fitted with seat belt pretensioners than the non air bag vehicles, with an older and more male driving population

The use of volumetric projections in Digital Human Modelling software for the identification of large goods vehicle blind spots

The aim of the study is to understand the nature of blind spots in the vision of drivers of Large Goods Vehicles caused by vehicle design variables such as the driver eye height, and mirror designs. The study was informed by the processing of UK national accident data using cluster analysis to establish if vehicle blind spots contribute to accidents. In order to establish the cause and nature of blind spots six top selling trucks in the UK, with a range of sizes were digitized and imported into the SAMMIE Digital Human Modelling (DHM) system. A novel CAD based vision projection technique, which has been validated in a laboratory study, allowed multiple mirror and window aperture projections to be created, resulting in the identification and quantification of a key blind spot. The identified blind spot was demonstrated to have the potential to be associated with the scenarios that were identified in the accident data. The project led to the revision of UNECE Regulation 46 that defines mirror coverage in the European Union, with new vehicle registrations in Europe being required to meet the amended standard after June of 2015

Effectiveness of airbags in Australia

General Motors - Holden's Automotive (Holden) was the first Australian manufacturer to introduce a package of new safety features with the release of the VR Commodore, including a driver's side airbag. This was followed two years later with a passenger airbag, released in the VS model. These airbags, in conjunction with an improved seat belt system, have the distinction of being specifically designed for Australian driving and accident conditions and as a consequence are different to those found in vehicles designed overseas. To determine the effectiveness of these systems the investigation of a number of field accidents has been conducted. The preliminary results of this work, although not all statistically significant, are very encouraging and suggest that the airbags have had a positive effect on reducing occupant injury with few of the negative side effects that are now being identified with some foreign airbag systems