Title: Reduce/ Prevent Whiplash Injuries in Car Accidents

Transcription

1 Title: Reduce/ Prevent Whiplash Injuries in Car Accidents (Anti- Whiplash Product) Author s name and affiliation: Rojin S Vishkaie 1 Author s affiliation address: Coventry University, Department of Industrial Design, School of Art & Design, Priory St, Coventry, UK, CV1 5FB Rojin S Vishkaie, Ph.D. student at the University of Calgary, Canada, I am currently undertaking a multidisciplinary Ph.D. program with the specialization in Computational Media Design particularly within the area of Interaction Design at University of Calgary, Canada, I also completed my Master s degree in Industrial Product Design at Coventry University, UK, My MSc final research topic is Reducing Whiplash Injuries in Car Accidents, Anti-Whiplash Product which totally focuses on the engineering side of design giving me an opportunity to study one of the important aspects of design e.g., engineering. Abstract The purpose of this investigation is to analyze whiplash injuries in car accidents from different angles as one of the most serious hazardous, and ultimately finding a possible solution to prevent/ reduce Whiplash injury which is the major aftermath of road traffic accident. To solve this problem, different influential causations of this hazardous have been explored such as vehicle and human factors, rear-end, side and head-on impacts and new technologies as they could help to achieve the better result. To conclude the research, possible solutions: design of the intelligent vertical airbag, intelligent exterior airbag, collapsible seat rail, airbag integrated curved head restraint and energy absorbent filler, have been recommended which try to satisfy the research question without compromising on the user experience. Keywords Whiplash Injuries/ Mechanism of Whiplash Injuries; Vehicle Factors; Human factors; Accidents Studies; New Technologies. 1 Present Address: University of Calgary, Faculty of Environmental Design & Department of Computer Science, 2500 University Drive NW Calgary, AB, Canada, T2N 1N4 Mobile: rojin.sv@gmail.com

2 Page No. Content...1 Abstract..3 Keywords 3 Introduction...3 Main Research...4 Definition of Whiplash Injuries...5 The Mechanism of the Neck Injuries Vehicle Factors: Mass, Speed, Seat belt, Head/ Neck Restraint System, Seat and Sitting Position Human Factors: Gender, Height, Age, Anatomy, Symptomatology Accident Studies:..10 Car Accident/ Whiplash Injury Causations, Impact Direction, Crash scenarios, Rear-end, Head-on, Side, Non-crash Accident New Technologies:...14 Anti-lock Braking System, Airbag, Side Impact Protection System (SIPS), Cockpit, Head restraint, Active Head restraint, WHIPS, SAHR, Bumper, Head Impact Rig, Active Anti Submarining, Pyrotechnic Prenetioner Safety:...17 Vehicle Safety, User Safety Literature Research Finding..19 Empirical Research Methodology..19 Analysis input data..20 Empirical Research Finding:...21 Observation, Questionnaire, Meeting Expert Conclusion 23 Design Brief...23 Performance Specification

3 Design Research...24 Idea Generation...24 Product Design Specification..25 Diagrammatic PDS..26 Design Proposal...27 Final Concepts...29, 30 Ergonomics Analysis Discussion.32 List of References 33 2

4 Abstract Globally, road traffic accident which has been widely recognized as a major threat of life and the second main cause of death among age years kills an estimated 1.3 million people and injures between twenty to fifty million people a year (World Health Organization 2009). Projection indicates that these figures will increase by approximately 65% over the next 20 years unless there is new commitment to prevention (World Health Organization 2009). In United Kingdom, according to the new report by Association of British Insurance (ABI), its member receive 1,200 claims of whiplash type injury every day, worth 2bn a year and whiplash related injuries cost NHS an estimated 8 million a year (BBC 2008). New technology features are growing to prevent this hazardous by providing high level of safety aspects, but still the frequency of injuries and death as a results of car accidents are high. The purpose and aim of this investigation is to analyze whiplash injuries in car accidents from different angles as one of the most serious hazardous, and ultimately finding a possible solution to prevent/ reduce Whiplash injury which is the major aftermath of road traffic accident. To solve this problem, different influential causations of this hazardous have been explored such as vehicle and human factors, rear-end, side and head-on impacts and new technologies as they could help to achieve the better result. Investigations lead to find particular solutions which some of them are inspired by the existing elements in road/ race car and altering them to more efficient solution. The report comprises research conducted with a range of qualitative and quantitative methods, starting from preliminary research to empirical research which has been conducted by means of user survey, questionnaire, contextual interview and direct observation. To conclude the research, possible solutions: design of the intelligent vertical airbag, intelligent exterior airbag, collapsible seat rail, airbag integrated curved head restraint and energy absorbent filler, have been recommended which try to satisfy the research question without compromising on the user experience. Keywords Whiplash Injuries/ Mechanism of Whiplash Injuries, Vehicle Factors, Human factors, Accidents Studies, New Technologies Introduction In today s world many safety features are available but still the risk of deaths and injuries and particularly Whiplash injuries as a result of road traffic accident which is now acknowledged to be a global phenomenon, is high. All countries of the world concern about the growth in the number of people killed and seriously injured on their roads (World Health Organization 2009). 3

5 Whiplash injuries have different causations which the main critical factors are road and vehicle conditions, infrastructure aspects, driving decisions, pedestrian behavior and impacts. Road traffic accident research has played a key role in understanding the main causations of car accidents and would help to improve the safety factors in order to decrease the number of accidents and possibly reduce the whiplash injuries. Development of both design and policy has effectively addressed the risk of accidents. For instance, designing the anti submarining, seat belt prenetioner, airbag, anti-lock braking system, active head restraint, driver information and assistance system for modern vehicles, signposts/ lighting/ traffic signals on roads, analyzing the driving/ riding behavior via CCTV which improves the driving manner, seem to be effective solutions to reduce the risk of whiplash injuries. Learning about impact and long term impairment from injuries leads to better design and applying new sophisticated technology tends to reduce/ prevent the accident and whiplash injuries. However, infrastructure and safety features are the other main accident prevention aspects which can be improved by road design. This research sets out to develop a design strategy in order to reduce neck and spinal injuries in low speed rearend, head-on and side crashes. The above interests and questions combine to form a research question, What are the most effective vehicle factors for the neck injuries in car accidents and how would it be possible to prevent/ reduce the problem?. The research is carried out by emphasizing on vehicle and human factors, accident studies and new technologies which are the initial aims and objectives. Finding a possible and viable solution to decrease the risk of whiplash injuries is the most critical criteria in this research. Conducting a series of questionnaire, contextual interviews and direct observation would prove beneficial in designing according to solve this hazardous. Further analysis of the findings would strengthen the research and lead to a set of design guidelines which is beneficial for the final design. Main Research The main research of this project comprises the most important section of the report which could be divided into the detailed subsections which are as follows: Definition of Whiplash Injuries The Mechanism of the Neck Injuries Vehicle Factors: Mass, Speed, Seat belt, Head/ Neck Restraint System, Seat and Sitting Position Human Factors: Gender, Height, Age, Anatomy, Symptomatology Accident Studies: Car Accident/ Whiplash Injury Causations, Impact Direction, Crash Scenarios, Rear-end, Head-on, side, Non-crash Accident New Technologies: 4

6 Anti-lock Braking System, Airbag, Side Impact Protection System (SIPS), Cockpit, Head Restraint, Active Head restraint, WHIPS, SAHR, Bumper, Head Impact Rig, Active Anti Submarining, Pyrotechnic Prenetioner Safety: Vehicle Safety: Active safety, Passive Safety User Safety: Reducing Injuries, Changing Behavior and Attitudes, Designing Safer Roads, Occupant Protection Definition of Whiplash Injuries Definition of Whiplash Term whiplash describes the mechanism of neck injuries which occur in automobile accidents and particularly in head-on, rear-end and side collision (Jackson 1977, and Malanga, and Nadler 2002: 1). The other definition of whiplash has been described as an acceleration-deceleration mechanism of energy transfer to the neck (Malanga, and Nadler 2002: 32). Whiplash is a common occurrence associated with the sudden forceful hyperextension or hyper flexion of head, neck and cervical spine. Injury occurs to multiple structures including muscle, tendon, ligament, bone, joint, and nerve tissues which can therefore result in traction, compression, rotation and a significant impairment and disability (Malanga, and Nadler 2002: 1). The Mechanism of the Neck Injuries From a mechanical and structural point of view, the cervical spine is a very complex mechanism. The human neck contains neurological, vascular and respiratory structures as well as the cervical vertebrae and spinal cord (Malanga, and Nadler 2002). Newton s law can describe the mechanism of neck injuries: a mass at rest remains at rest until acted upon by some external force and a mass in motion remains in motion until acted upon by some external force (Jackson 1977: 88). Rear-end collisions causes a sudden acceleration of the body which in this situation, the head, being a mass at rest, remains at rest until acted upon by some external force. The flexibility of the neck results in forceful hyperextension of the neck as the body is accelerated forward. The head hits the head restraint and this impact plus the reflex contraction of the neck muscles start the head in forward motion. The head continues forward motion until it is acted upon by some external force such as, contact with some stationary portion of the car and/or the restraining action of the soft tissue structure which hold the head and neck on the body. Sudden deceleration of a moving vehicle occurs in a head-on collision with another vehicle or a stationary object. In this situation the body of the passenger is unsupported from the front, it is thrown forward and it continues its momentum until it strikes some stationary part of the car such as steering wheel, windshield or dashboard. The head continues forward movement until it hits an immovable object, or until it is acted upon by some external force, then it recoils in extension (Jackson 1977). It is suspected that the biological cause of long- term whiplash symptoms is nerve damage while short- term pain may be minor strain and sprain. 5

7 Strain and sprain describe the Injuries of ligaments and muscles. Strain injury indicates that the joint structures have been placed under stress or tension by sudden force, or they have been stretched slightly beyond their usual elastic capacity. Sprain injury indicates that the joint structures have been stretched beyond their functional capacity and resulting in tearing of various degrees from their attachment to the bones which produce a rending and forcing. The greatest amount of stress and strain on active movement of the cervical spine in hyperextension occurs at the C4-C5 level and in hyper flexion occurs at the C5-C6 level (Malanga, and Nadler 2002), Figure 1: Studies suggest that nerve damage and long- term symptom can occur with the milder level of neck distortion. One hypothesis is that nerve damage is caused by motion of adjacent neck vertebrae during a crash. Another hypothesis suggests that the nerve damage is cause by fluctuation in spinal fluid pressure arising from neck distortions (Insurance Institute for Highway Safety 2009). Vehicle Factors Figure 1. Neck Injury (Neck Injury n. d.) Mass: Vehicle mass is one of the effective factor which has been investigated that there is a strong link between vehicle mass and whiplash injury risks, with a fivefold difference in risk factor between the best (large mass) and the worst (low mass) cars. However, there are large differences between vehicles of similar mass, which they have difference in vehicle structure and the seats (Koch et al. 1995, and Eichberger et al cited in Minton et al. 1998: 6). The likelihood of whiplash injury claim are more for heavier vehicles than the vehicle which has approximately equal or lesser mass. However, drivers of rear-struck cars are more likely to claim a neck injury than drivers of rear-struck SUVs (Insurance Institute for Highway Safety 2009). Speed: Impact speed is another most effective factor. The mass and speed of the involved vehicles and/ or the change in velocity of the target vehicle are the primarily determinants of delta V. The forces acting on an occupant are more a function of delta V than the speed or mass of the vehicles. If the target vehicle is moving in the same direction as the bullet vehicle prior to a rear-end collision, the difference in their speeds will determine the effective impact velocity. The risk of injuries in rear-end impact tends to increase with delta V (Malanga, and Nadler 2002: 33). Seat Belt: Seatbelts are estimated to reduce the overall risk for serious injuries in crashes by 60-70% and the risk for fatalities by about 45 percent. According to the studies of real frontal crashes, wearing a seat belt 6

8 increases the risk of whiplash injuries. But it is hard to find clear evidence that wearing a seat belt in low severity rear end crashes increases the risk of neck injuries (Insurance Institute for Highway Safety 2009, and Minton et al. 1998: 6, 8). Head/ Neck Restraint System Head restraint is an essential safety feature which prevents the excessive head and neck kinematics and displacement during rear-end collisions. Effective head restraints help to move an occupant s head forward with the body in a rear- end crash and decrease the likelihood of sustaining a whiplash injury. However, there are some important aspects about the head/ neck restraint, such as: 1. An effective head restraint should have a good geometry which poses behind and close to the back of an occupant's head to prevent a whiplash injury in a rear- end collision. A restraint should be at least as high as the head's center of gravity or about 9 cm (3.5 inches) below the top of the head. The backset or small horizontal distance between head and restraint which must be 5.58 cm (2.2 inches) has been found that to have no effect on initial disability for long term outcomes. Backsets should be as small as possible, due to the distance of more than 10 cm (about 4 inches) have been associated with increased symptoms of neck injury in crashes (Insurance Institute for Highway Safety 2009, and Minton et al. 1998), Figure 2: 2. The restraints are measured with the angle of the torso at about 25 degrees which shows a typical seatback angle. Each restraint is classified according to its height and backset into one of four geometric zones: good, acceptable, marginal, or poor (Insurance Institute for Highway Safety 2009, and Seiffert, and Wech 2007), Figure 3: Figure 2. Head/ Neck Restraint system (IIHS 2009) Figure 3. Restraint Classification (IIHS 2009, and Seiffert, and Wech 2007) 3. The head/ neck restraint should be high enough to prevent the head of the occupant from acceleration over the restraint which a minimum height of the adjustable head restraint in their lowest position must be 29.5 inches from an occupant's hip to the top of a head restraint. Head restraints will not be required in rear seats, but if they are voluntarily installed they must meet a height requirement. Fixed restraints in rear seats must be at least 29.5 inches from an occupant's hip, and adjustable restraints cannot be adjusted below 29.5 inches. There will not be a backset requirement for head restraints installed in rear seats (Insurance Institute for Highway Safety 2009, and Minton et al. 1998), Figure 2: 4. A restraint system should have enough adjustability to accommodate a broad range of occupant sizes and should lock in place. Adjustable head-neck restraints have been found to be significantly better than either fixed 7

9 restraints or no restraints for males in rear impacts. However, studies indicate that fixed restraint is more effective for female (Minton et al. 1998), Figure 2: 5. A head restraint should be close enough to the back of the head and neck in order to prevent extreme hyperextension of the neck and minimize the relative motion between the head and torso. In addition, a head restraint should have a neck counter to enable support of the cervical lordosis. Head restraints alone are not enough to prevent all whiplash injuries (Minton et al. 1998), Figure 4: Figure 4. How to Adjust Your Head Restraint (ROSPA 2009) 6. Accident studies show that modern and strong seat without a head restraint and eliminating elastic rebound from the seat without restraint has the highest risk of neck injury (Minton et al. 1998: 7). 7. At lower severity rear- end crashes, some factors like the head restraint and seat back geometry and cushion properties and at higher severity rear end crashes, the seat force-deflection characteristics are more important (Minton et al. 1998). Seat and Seating Position Elasticity of seat back has been considered that collapse of seat back in a rear impact has a beneficial effect on neck injury outcome which reduces the head rotation and neck load (Muser et al cited in Minton et al. 1998). However, there is a critical correlation between disability and seat back angle and seat back height. It has been shown that seatback with the better energy absorption characteristics could provide higher level of protection for out of position occupants in rear end crashes. However, stiffer seatbacks tend to increase loadings on the cervical, thoracic and lumbar spine in rear- end impact. 8

10 It is uncertain which seating position exposes an occupant to the greatest chance of neck injury. Studies have demonstrated that drivers have a higher risk of injury than passengers, due to they are prone to move forward and away from the seatback as they reach for the steering wheel and observe traffic around them, whereas passengers usually are more relaxed and lean further back in their seats, with their heads closer to the restraint, however it has been found that moving to the rear seat is nearly twice as effective as tilting a head restraint to the front seat in reducing whiplash injury risk (Insurance Institute for Highway Safety 2009, and Minton et al. 1998). Human Factors Gender: Females are 1.8 to 2.2 times more at risk of whiplash injury in all types of collisions than men. A Swedish study found that females with whiplash injuries are more at risk of developing long-term symptoms, due to they are more susceptible than male to neck injuries. Fifty-five percent of females who sustained whiplash injuries are susceptible to develop long-term symptoms compared with 38 percent of males (Insurance Institute for Highway Safety 2009). It has been shown that the risk of disability for female drivers is three times higher than for males. However, risk of injury for females in rear seats is four times higher than males due to males have stronger neck muscles than females with approximately the same size of head (Insurance Institute for Highway Safety 2009). Height: Height is one of most important risk factor particularly among females for neck injury. Shorter people often are protected by unadjusted head restraints. Stature may not play as significant role in the severity of injuries among males because many head restraints are too low to protect even shorter males (Insurance Institute for Highway Safety 2009). However, taller occupants who do not adjust their head restraints are more likely to sustain whiplash injuries (Minton et al. 1998). Age: Child and old people are more at risk of whiplash injury. Symptomatology: Patients normally develop symptoms within 24 hours after a whiplash accident. The symptoms of whiplash are dominated by pain in the neck and headache. The second most common symptom is pain in the shoulder gridle, followed by weakness in the upper limbs. In addition, dizziness, visual disturbances, concentration, cognition and memory disturbances and tinnitus are less common and irregular symptoms. However, approximately 10% of all whiplash injuries become long-term injuries in rear crashes and about 5% in frontal crashes (Malanga, and Nadler 2002). Anatomy: Cervical Vertebrae Cervical spine is divided into two functional regions: the upper (C0-C2) and lower (C3-C7). By another meaning, the cervical spine is composed of seven vertebrae, including three atypical and four typical vertebrae. The typical cervical vertebrae, (C3-C6) are composed of a vertebral body and a vertebral arch and muscular attachment (Malanga, and Nadler 2002). 9

11 Different parts of the cervical spine are: Intervertebral Discs, Ligaments, Cervical Spinal Canal, Spinal Cord, Nerve Roots, Vertebral Arteries, Muscle of the Cervical Spine. The anatomy of the cervical spine is complex and allows for a high degree of motion while serving as a protective conduit for the spinal cord and nerve roots (Malanga, and Nadler 2002), Figure 5: Accident Studies Car Accident/ Whiplash Injury Causations Figure 5. Spinal Cord (Spinal Cord n. d.) There are some crash causations which are the major causalities of whiplash injury which could be divided into the road and vehicle condition, infrastructure, pedestrian and driving behavior, impact with other vehicle or/ and braking hard. Studies of the road safety have shown that human error is the main cause in 57% of all accidents and is a contributing factor in over 90%. In contrast, only 2.4% is due to mechanical fault and only 4.7% is caused only by environmental factors (Green, and Senders n. d.). The majority of car accidents seem to be caused by bad driving behavior: driver inattention, failure to merge, speeding, racing, aggressive driving and failure to exercise care in passing. Accidents can be attributed to specific causes apart from poor driving behavior itself include: falling asleep; weather usually (Snow, Ice or 10

12 Rain and fog); alcohol, drugs and drunk driving; driver distractions from in-vehicle sources including mobile phones, insects in the car, playing music, conversation with a passenger; collisions with other vehicles and/ or animals on the road, braking hard usually due to unexpected barrier/ object/ car and/ or bad pedestrian behavior on the road, not maintained vehicle, vehicle malfunction and infrastructure/ road condition normally with providing poor vision system such as inappropriate lighting system at night and poor informative and visible traffic signals and signs (Green, and Senders n. d.). Impact Direction Whiplash injuries occur in all impact directions such as rear- end, head- on and side collision. Approximately 50% of the whiplash injuries occur in rear crashes, 30% in frontal crashes and the rest in other types of accidents. Rear impact has been found to be significantly less injurious than other impact directions in terms of long term outcome for male. Females showed no consistent trend in this respect but in some cases their average disability is non-significantly higher in rear impacts (Insurance Institute for Highway Safety 2009, and Minton et al. 1998). Crash Scenario Crash scenarios which is based on crash causations explain where, when and how rear-end, head-on and side impact occurs. Rear- end impact: Typical scenario for rear- end collision is a sudden deceleration by the first car (e.g., to avoid hitting pedestrian) the following car that does not have time to brake and collides with the first car, Figure 6: Figure 6. Rear- end Impact Head- on impact: Typical scenario for head- on collision is when the front end of two vehicles hit each other, Figure 7: Figure 7. Head- on Impact 11

13 Side impact: Typical scenario for side collision is when the side of one or more vehicles are impacted. These crashes often occur at intersections and/ or parking lots when two vehicles pass on a multi lane road way or when a vehicle hits a fixed object, Figure 8: Figure 8. Side Impact Rear-end Impact Forceful hyperextension of the neck occurs when the body is accelerated forward and causes traction on the anterior longitudinal ligaments. If the head is rotated to one side and titled to the opposite side, the torisonal effect causes greater damage on one side than the other side. Rear-end impact causes very rapid backward-forward motion of the head and upper torso. The extension phase of the motion causes the most injuries. At this time head continues backward motion which muscles unable to control the head, until the inappropriate processes of the vertebrae crush together to provide some countervailing force and breakage of the vertebrae. The flexion phase of the motion is limited by contact between the chin and the chest which is within the natural range of the head. Hence, the provision of a head restraint is to prevent rearward hyperextension of the neck from severe injuries, and also soft tissue from less severe injuries (Seiffert, and Wech 2007, and Jackson 1977), Figure 9: Figure 9. Rear- end Collision (Jackson 1977: 89) 12

14 Head-on Impact Forceful hyper flexion of the neck occurs when the body is decelerated suddenly and causes tear or stretch the nuchal ligament, the posterior longitudinal ligament, the interlaminar ligaments, the capsular ligaments of the lateral inter body joints and the posterior joints. Frontal impacts cause sudden deceleration of the torso which its main injury is the forward flexion of the neck (Seiffert, and Wech 2007, and Jackson 1977), Figure 10: Side Impact Figure 10. Head- on Collision (Jackson 1977: 89) Side collision occurs when the side of one vehicle is hit by the front end of another vehicle which usually occurs at intersections of stress or roads and may result in injuries depending on the force of impact, the position of the head and the effect which is produced by the construction of the vehicles involved. In this situation, actual tears of the lateral neck muscles, tearing of the alar and atlantoaxial ligaments and upper joint capsules may occur (Seiffert, and Wech 2007, and Jackson 1977), Figure 11: Figure 11. Side Collision (Jackson 1977: 89) 13

15 Non- Crash Accidents Whiplash Injuries may result from sudden acceleration and deceleration of vehicles even in the absence of crash accidents. The rapid acceleration of vehicle may cause a forceful hyperextension of the neck of an unsuspecting passenger. The sudden acceleration of a vehicle, which occurs due to sudden hard brake which perhaps avoid a crash accident, but the unprepared passenger may keep going into the dashboard or the windshield, the back of the front seat or onto the floor. Using seat belt properly could prevent the forward propulsion of the body and could lessen the possibility of serious injuries of most of body from sudden deceleration of the vehicle (Jackson 1977: 103). New Technologies Anti-lock Braking System: This system is for electronic differential control which is sufficient to prevent a traction wheel from spinning when starting a vehicle on a surface with a different coefficient of friction. At higher speed (e.g., above 20 km/h), the effect is reduced. Above 40km/h, the system is switched off to avoid a negative influence with respect to safe driving under high speed (Seiffert, and Wech 2007). Airbag: There are different kinds of air bag in the car which can be categorized in the following groups: airbag for frontal and side impacts and additional air bag applications such as: door, side curtain and knee airbag. Side Impact Protection System (SIPS): The side impact protection system has been designed in order to reduce/ prevent significantly the risk of injuries by dissipating the energy of side impact across the side of the car by having the driver and passenger seat integrated on transverse seat rail. The SIPS has been provided by side curtain airbags which offer support for occupants in side impact by supplying a large side coverage area in side of the vehicle (Science Daily 2008, and Autoliv 2009). Cockpit: Cockpit has to be a crashworthy, safe and strong structure which does not collapse during impact and could protect occupants up to the limiting acceleration of the human body by energy absorbing element. Hence it should prevent deaths and serious injuries. A strong compartment includes the area from the dashboard to the rearmost headrest mounting which should protect all parts of the human body (Roger 2007). Head restraint: There are three common systems in order to prevent/reduce whiplash which are becoming more common on vehicles. 14

16 Active Head Restraint An active head restraint is an adjustable device like standard head restraint and includes the pressure plate and a pivot system in the seat back. It has other features which provide comfort for occupant, such as adjustable shoulder and lumber support. During rear-end impact, active head restraint optimize the anti-whiplash performance of seat which the front section of the head restraint moves forward and upward to reduce the distance between the head and the head restraint and a longer period of support for the head during (ROSPA 2009), Figure 12: Figure 12. Active Head Restraint (Active Head Restraint n. d.) WHIPS (Whiplash Protection System) WHIPS seats have a fixed and integral head restraint, however, the entire seat back has been designed in order to provide good geometry and protection for occupant from whiplash injuries. During a rear impact, the seat moves backward and becomes reclined and an expandable hinge at the base of the seat back which is designed to be used once and should be replaced following the accident, controls its movement, so it keeps the movement of the head and body together and increases the length of time that the occupant is in contact with the head restraint (ROSPA 2009), Figure 13: SAHR (Saab s Active Head Restraint) Figure 13. WHIPS (Automobiles Review 2009) According to the study, SAHR provided a 43% reduction in neck injury claims, 55% reduction in claim rates for women and 31% reduction in claim rates for men (Insurance Institute for Highway Safety 2002 cited in 15

17 SAABHISTORY 2009). SAHR has lumbar pad in the seat back which when is contacted by occupant in rearend impact, causes a lever to move the head restraint forwards and upwards to support the occupant s head and neck (CARSPACPSER 2009), Figure 14: Bumper Figure 14. SAHR (IIHs 2009) Vehicle bumper system is part of vehicle safety system which has some important features such as energy absorption, high performance, damageability, damage prevention, easily and cheaply can be repaired. Bumper design and different level of stability, stroking energy absorption, construction styles, bumper bar torsion and compliant bumper covers and foam are some of the important factor. Today's bumpers are made with a reinforcement bar of steel, aluminum, fiberglass composite or plastic with a plastic cover. The system includes crash absorbing mechanisms that compress on impact, such as polypropylene foam or plastic honeycomb. The most effective bumpers are positioned with distance between the reinforcement bar and the vehicle's sheet metal (Avery et al. n. d.), Figure 15: Figure 15. Cross Section of Different Bumpers (Avery et al. n. d.) 16

18 Head Impact Rig: Seat head restraint has energy absorption characteristic which could reduce/ prevent the severity and occurrence of whiplash injuries. The main considerations in this design are minimization of stress level, deformation, modes of vibration and variety of configurations for the impactor (MIRA n. d.). Active Anti Submarining: Submarining occurs when the leg and pelvis get injured while occupant's knees hit the instrument panel during front-end collisions/ emergency braking or when the lap belt is not strapped tightly, however the sudden deceleration can cause occupant to slide down under the lap section of the seatbelt which could increase the risk of injury dramatically such as serious abdominal, pelvic and spinal injuries. In order to reduce the submarinig effect, an active ramp is integrated into the seat. During a head- on collision, the ramp rises quickly and the bar in the front section of the seat restrains the forward movement of the pelvis. If the occupant is seated in the correct position, the risk of impact to the knees from the instrument panel is reduced, and the belt forces acting on the body are reduced. In frontal impact, forward displacement of the pelvis is reduced by more than 30% with the Active Anti-submarining system (Johnson Controls 2006, and Faurecia 2009). Pyrotechnic Pretensioner: Pyrotechnic pretensioner is applied either as part of the belt, above the seat belt retractor or integrated into the retractor itself. The pretensioning function is activated by a sensor-triggering signal which could be a mechanical or an electronic sensor, with the relevant electronic control unit (Seiffert, and Wech 2007: 192). Safety Vehicle Safety There is a direct relationship between comfort and vehicle safety which has been synonymous with occupant protection, preventing and avoiding accidents, reducing the severity of the collision when is unavoidable and providing as much protection as possible to all involved. Vehicle safety can be subdivided into three main areas Accident avoidance (Active Safety): All measures that serve to prevent accidents. Mitigation of injuries (Passive safety): All measures that help to reduce injuries during and after the accidents. Pre- crash safety: All measures to reduce the severity of an accident after the sensor detects that a sever accident is unavoidable (Seiffert, and Wech 2007: 3 and MIRA n. d.), Figure 16: 17

19 INTEGRATED VEHICLE SAFETY ENGINEERING TESTING ACTIVE SAFETY PASSIVE SAFETY CRASH MITIGATION Figure 16. Integrated Vehicle Safety Engineering (MIRA n. d.) A) Active safety: Developing chassis control system and anti-lock braking system to help the driver avoid accidents or systems that take control to prevent a collision. Advanced information driver systems, warning and assistance systems, pedestrian and vulnerable road user awareness, collision avoidance and intervention systems, advanced driver assistance systems- braking and vehicle control which can help to prevent an accident occurring in the first instance [primary safety, such as lighting, braking, handling and ergonomics (vision system)] and system which can help to save lives when a crash does occur [Secondary safety], (MIRA n. d., and Transport Research laboratory 2009). B) Passive safety: Developing body structure and restraint system to protect vehicle occupants in severe and potentially fatal crashes and design and development of seat engineering, pedestrian and vulnerable road user protection, (MIRA n. d., and Transport Research laboratory 2009). However, the main factors which improve the safety features in car design are vehicle structure and design, vehicle restraint system which has a tolerable deceleration level, absorbs energy and keeps the occupant compartment intact. User Safety Reducing Injuries: Children who are younger than 12 years old and are smaller than 150 cm in height must be placed in special child restraints in vehicle (Seiffert, and Wech 2007). Changing Behavior and Attitudes: The research has identified new psychological methodologies for traffic calming such as making a road appear narrower than it actually is. This changed protection of the road influences driver behavior and is an effective means of reducing excessive speeds (Transport Research Laboratory 2009). Designing Safer Roads: Intend to reduce the risk of injury and enhance the road safety, there are various design features which the most important ones are to design a safe road layout and control driving at the appropriate speed. 18

20 Occupant Protection: In order to develop the occupant protection, restraint system should be developed which there must be facilities for occupant to differentiate between devices that must be activated manually by the occupant (e.g., seat belt and child restraints) and devices that work automatically (e.g., seatbelt movement limiters, belt tensioners and airbag). In addition robust and safe occupant compartment which withstands a wide variety of impacts is one of the main aspects intend to provide higher level of protection (Seiffert, Wech 2007: 151). Literature Research Finding The outcome of the literature research has demonstrated that road traffic accident kills an estimated 1.3 million and injures between twenty to fifty million people a year globally. However, over half of the all car occupants involved in road traffic accidents, had whiplash injuries (Minton et al. 1998: 3) Whiplash is an acceleration-deceleration mechanism of energy transfer to the neck. It may result from rear end, head-on and side collision, but can also occur during diving or other mishaps. The impact may result in bony or soft tissue injuries (whiplash injury), which may lead to a variety of clinical manifestations. In crashes the main issue is the vehicle s body structure and safety system such as seat and head restraint as one unit which can absorb energy in a controlled manner and gives support for the whole spine in low speed crash in order to reduce the risk of injury. In frontal crashes the air bag, seat belt pretensioner and load limiter probably must work together in reducing the acceleration. There are three different anti-whiplash seats on the market which have been the most effective device for reducing whiplash injuries so far. The WHIPS seat (plastic deformation) the SAHR seat (active head restraint) and a seat made by Toyota that could reduce the injuries. There are two general principles to apply these devices, one propels the head restraint forward to meet the head and thereby reduces the relative head torso movement; the second principle allows the occupant to move backward until both the head and the spine are supported from the seat closer in time. Thereafter if the forces are high, the seat reclines and thereby reduces the acceleration. However, there are many vehicle and user safety features such as vehicle energy absorption, driving at appropriate speed, etc which improve the level of safety for occupant. Empirical Research Methodology The empirical research methods which have been used in this investigation comprise qualitative observation, quantitative questionnaire and qualitative interviewing expert. The aim of the observational research in this project is to introduce basic and flexible issues of this research topic, before undertaking more structured research such as form a questionnaire and interview the expert. So 19

21 the observational information has been collected by looking at the car accident scenarios and crash tests on different reliable web sites. The aim of the questionnaire which comprises pre- pilot (n 1 = 5) and pilot (n= 15) investigation is that to collect usable information to find out which vehicle factors/ elements are more effective in order to prevent/ reduce whiplash injury in car accidents, from the members of the market- specific population which include twenty lecturers of department of industrial design and some of the MSc. Industrial Product Design, Transport and Design and Ergonomics and Design students, Coventry University, n= 20. The aim of interviewing expert is that to obtain information to analyze more in depth the causations of car accident and mainly whiplash injury, new vehicle technologies and find out the possible ways to prevent/reduce whiplash injury in car accidents which is known only to expert of vehicle safety, car accident causation and particularly whiplash injuries. The interview took place at Coventry University, Department of Industrial Design with one of the lecturers, Lee Hall. These investigations began with a list of questions (prepared by myself) which has been noted ten questions for questionnaire and thirty questions for interviewing expert, each concerned with a point of design about which have been doubtful during the process of this project. Analysis input data The quantitative analysis of the data shows that the vast majority of the market-specific population (n= 20) would like to feel safe and they do agree that restraining driver and passenger is an essential safety aspect to protect them from whiplash injuries at the time of accident, but also they do agree that the feasibility of using/ accepting restraint system like neck and chest restraint which are common effective protective elements in motor racing/ F1 is less, due to they are highly restrictive, difficult to use, cumbersome, less comfortable and also the variety of sizes and shapes in a road car occupant are high. However, figures demonstrate that seatbelt, airbag and active head restraint which are primary safety aspects and safety cell, low speed, crumple zone which are secondary safety aspects have been the most effective protective devices to prevent/ reduce the likelihood of whiplash injuries due to the chance of survival or survival with minor injuries by using/ applying them become greater due to they are comfortable, easy to use and they do not pose any problem and constraint for passenger and driver who expect some freedom of movement for comfort visibility and the ability to operate controls. 1 n= Market- Specific Population 20

22 Empirical Research Finding Observation: The observational research findings have shown that how car accidents would occur (see Accidents Studies) and how existing vehicle technologies would help to prevent/ reduce the whiplash injuries (see New Technologies), by looking at the crash tests including dummies in simulated rear- end, head- on and side impact, in order to investigate the performance of the car technology elements and find out what are the causations of the car accident. In addition this technique of empirical research helps to find out the Injury prevention which is based on accident analysis, and also would helps to understand the loading environment and determine the injury mechanism, leading to the development of priorities for injury prevention. Questionnaire: The outcome of questionnaire has shown that road car occupants would prefer to be safe with less restriction and difficulties. However, they think conventional seatbelt, airbag, active head restraint and automatic options/ settings are the appropriate and comfortable devices to reduce the likelihood of whiplash injuries in car accident, due to they provide more freedom of movement for comfort, visibility and the ability to operate controls, but also the fact has shown that none of these devices and alternative ways have been entirely successful to reduce/ prevent the this problem. Meeting expert: The outcome of interviewing expert has shown various information which are as follows: 1. In terms of reducing/ preventing whiplash injuries in car accidents, the most effective ways would be preventing/ reducing whiplash injury itself or preventing car accident itself, however, there should be focus effort on one particular area which offers the best result, due to, it is difficult to entirely eradicate collision, but the analysis of the crash causation would be useful. 2. The main causations of the rear- end, head- on and side collision are: vehicle malfunction, not maintained vehicle, road condition/ camber, environment and weather condition such as fog and ice, not educated driver, driver distraction high speed and sleepy driver. 3. In terms of reducing whiplash injuries, reducing energy at the occupant position is the best achieved by scarifying material structure to absorb the energy and deform themselves. However, to prevent excessive occupant movement also prevent safe driving in some cases. A crash helmet and neck brace are widely used in the motor sport industry which could be adapted to the road car but would be unpopular. 4. The existing technologies in car increase the severity of accidents and injuries, therefore distraction internally could be reduced by limiting the amount of information displayed to the driver. However, driving environment externally is cluttered with signs and non standard information displayed which should be reduced in order to reduce the severity of accident s and injuries. 5. Pyrotechnic pretensioners are the most effective breakthrough in technology for reducing whiplash injuries in rear- end, head- on and side collision, however other technologies such as anti submarinign, car seat and etc are to limit the other types of injuries. In addition, low speed could help to reduce/ prevent car accidents, hence reduce whiplash injuries incidence. 6. Three kinds of airbags such as: side, knee and front airbag are to limit injuries not to remove them and also they cause injuries themselves, for instance frontal airbag limits whiplash but in a small way. It is the pretensioner, SIPS head restraint technology and IIHS head restraint positioning rules which help to reduce injuries in this area. 21

23 7. The car seat, seat belt, airbag and etc prevent the excessive movement of the occupant which limit both incidence and severity of injury but they also assist in reducing other injury criteria. 8. There are front and curtain side airbags in car which protects the occupant while accident from front and right hand side of driver and left hand side of front occupant, so to protect the other side of occupants an anterior bag system from the center console binnacle may be possible but would increase the repair cost and they would require extensive development. 9. Mostly front and rear decelerations such as head- on collision, offset front and rear impact are the types of collision which lead to whiplash injuries. 10. If the occupants move approximately less than 60mm, therefore it leads to less force being transferred to the neck and head. 11. Whiplash is difficult to diagnose and therefore easier to claim for. Also whiplash is more prevalent as there are more collision types. 12. Flexible material like gel and/ or bullet proof / Kevlar, non- Newtonian flow and etc, should explore in tend to absorb and dissipate as much kinetic energy as possible in order to decrease the level of forces transmitted through car, so it would be possible to use this kind of material in bumper and body of car in order to prevent whiplash injuries. 13. Seat belt pretensioner, honeycomb structure beneath head strike area such as B pillar have been the most effective interior and exterior elements in order to protect occupants. 14. In order to reduce/ prevent whiplash injuries, head and upper torso should be kept to move together, therefore, neck brace from motor sport would be one of the most effective ways. 15. In F1 it is ok to hold the drivers head more formally. However, it would be possible to apply this system in a production vehicle, but it would need a great deal of public support and this would require careful management. 16. Using a more restrictive head restraint, neck brace and chest restraint such as a 4- point belt and harness could help to reduce the risk of whiplash injuries, but there are some barriers for occupants to use these devices such as time acceptance, looks and level of occupant education. 17. In order to protect rear occupant at the moment of accident, the same protective elements should be used, due to they have the same deceleration. 18. Deployments of intelligent vertical airbag could help to reduce/ prevent whiplash injuries but it needs supplement due to, it might causes other injuries such as facial burns. 19. The dashboard location is not related to whiplash injuries, its location is more likely to strike injuries but these are very rare. 20. ISOFIX restraint/ child car seat for children are designed to limit the risk of injuries, but medically the recovery time for children should be slightly better. However children should be kept away from the airbag. 21. The risk of injury becomes higher for old people because of general degeneration and/ or reaction time. 22. In order to reduce/ prevent the risk of injuries for occupants who are at sleep, there should be the designed device to lead to a correct position of head/ neck, for instance upright position, which their tissue would react in a same way (Hall 2009). 22

24 Conclusion Design Brief Much knowledge has been gained about the nature and cause of whiplash injuries. This research report is an attempt to summarize the findings and proposes the directions which could help to counteract the injury risk, due to reduce the whiplash incidence and severity of injuries in all situations which is difficult to achieve. Therefore there should be a focus on reducing the maximum occupant acceleration/ deceleration, using the vehicle s body structure and safety system. One of the major aspects which has to take into consideration in tend to reduce/ prevent whiplash injury is to dissipate/absorb the kinetic energy in order to decrease the level of transmitted forces of the collision. Hence, apart from the conventional solution of seat and head restraint design which could help to reduce the risk of injury but it is not necessarily the effective way to solve the problem, there should be a concentration on the other aspects which would be more effective such as: seat rail structure, using different kind of material, using the existing safety elements like airbag which deploys in a different way and etc. The other most important parameter to attempt to mitigate this problem is that to study about road and vehicle safety and standard features that will cause a beneficial effect in injury reduction and severities in the future. However, analysis the neck injury mechanism may be more effective approach to the problem due to the exact mechanism of injury is still unknown. Performance Specification There are several tentative suggestions intend to prevent/ reduce whiplash injuries and protect occupant in car accidents, which outline this performance specification. To install the airbag which deploys from the different direction from conventional airbag, in order to prevent/ reduce forward movement of the head/ neck in rear- end and head- on collision. Design of the curved head restraint, in order to support the head/ neck from tilting in side collision. Design of the cushion or airbag which deploys from the exterior of the car, in order to dissipate/ absorb energy intrusion of impacting car. To use the different kind of material such as flexible, strong, energy absorbent material and etc in the car body which can dissipate/ absorb the kinetic energy in order to decrease the level of transmitted forces of collision. Design of the collapsible seat rail which can dissipate/ absorb the kinetic energy of collision in order to decrease the level of transmitted forces of collision. 23