CHARACTERISTICS OF ANTI-WHIPLASH SEAT DESIGNS WITH GOOD REAL-LIFE PERFORMANCE

Ola Bostrom*, Anders Kullgren** *Autoliv Research, Sweden **Folksam and Karolinska Institutet, Sweden

ABSTRACT In the last 10 years car seats have been specifically designed to mitigate short and long-term neck injuries caused by rear end impacts. During this period of time, anti-whiplash seat ratings also have been introduced. Recent research have shown rating methods to correlate to real-life performance. The objective of this study was to describe possible characteristics of real-life good performing anti- whiplash seat designs. To meet the objective, first a real-life data analysis was performed. In total 1111 Folksam and 2630 police reported injuries between 1998 and 2006 were included. As a result, the redesign of the Saab, Volvo and Toyota seats in the late 90s showed a 50-70% reduction in risk of whiplash symptoms for more than 1 month. Secondly, a rating test series with Saab, Volvo and Toyota seats before and after the anti-whiplash redesign were performed. Also, published rating performances of seats with these designs were analyzed. As a conclusion, possible characteristics of good performing seats were good performance in dynamic rating tests, especially for the low and medium severity pulses, through designs aimed at reducing head-to-head restraint distance and yielding/energy absorption of the seat.

Keywords: Disabled, Neck, Rear impacts, Seats, Whiplash

Long-term neck injuries caused by rear-end impacts have been an issue since the first car seat was designed. According to Krafft (1998) the risk of injury was doubled in car models from 90s compared to 80s. In the late 90s, the first rear-end impact crash test dummy was launched as a result of a Swedish research program. A few years later, the first public dynamic ratings of anti-whiplash seat designs were introduced by IIHS, Folksam/SRA, Thatcham and ADAC. In these rating tests, both seat evaluations as well as injury parameters were used. In a study by Kullgren et al (2003) of numerical reconstructions of real-life crashes, the predictability of the dummy evaluation parameters NIC and Nkm were shown to be applicable in seat evaluation. Moreover, for these parameters risk curves for more than one month of symptom duration were established. Real-life rear-end impact performance of various cars have been published (IIHS; Folksam) and recent research by Kullgren et al (2007) has shown that public ratings of seats do correlate with real-life performance. Although it is known that overall rating performance does reflect overall real-life performance, the characteristics of good seat designs are less known. Studies have indicated that headrest geometry, including head-to-headrest backset, reduces risk of injury (Jakobsson, 2004; Nygren, 1985). In a study where 8500 cars with poor headrest geometry were redesigned with yielding seat attachment brackets (YSAB), the yielding function (the only design change) was shown to considerably reduce the risk of whiplash injury leading to long-term consequences (Krafft et al, 2004). Also, the car manufacturers Saab and Volvo have shown their SAHR (Saab Active Head Restraint) (Wiklund and Larsson, 1997) and Whips (Whiplash Protection System) (Lundell et al, 1998) systems to be effective in real life rear- end impacts (Viano and Olsén, 2001; Jakobsson, 2004). Adding the Toyota WIL (Whiplash Injury Lessening) system (Sekizuka 1998), these three systems were claimed by each car manufacturer to be designed to reduce head-to-headrest distance and/or yield/absorb energy in a force controlled manner. The objective of this study was to describe possible characteristics of real-life good performing anti-whiplash seat designs. Therefore, a real-life as well as dynamic rating analysis was performed of Saab, Volvo and Toyota car models just before and after the SAHR/Whips/WIL redesign. In addition, published rating of seats with these designs was included in the analysis.

IRCOBI Conference - Maastricht (The Netherlands) - September 2 007 219 METHOD The method and result sections are divided into two sub-sections, a real-life performance and a dynamic rating performance section. REAL LIFE PERFORMANCE - The real-life evaluation was based on two different data sources. To calculate the proportion of injuries leading to long-term symptoms (defined below) all whiplash injuries in rear-end crashes reported to the insurance company Folksam between 1998 and 2006 were used. In total 1111 reported whiplash injuries were included. To calculate relative risk of an injury in rear-end crashes all two-car crashes reported by the police between 1998 and 2006 were used, in total 2630 crashes. Injury classification - Claims reports including possible medical journals for all crashes with injured occupants between 1998 and 2006 were examined. Whiplash injuries reported in rear-end crashes within a range between +/-30 degrees from straight rear-end were noted. Insurance claims were used to verify if the reported whiplash injuries led to long-term symptoms. Occupants with long-term symptoms were defined as those where a medical doctor examined the occupant and the occupant claimed injury symptoms for more than 1 month, which corresponds to a payment of at least 2000 SEK (about 300 US$) in the claims handling process used by Folksam. Out of the 1111 persons reporting a whiplash injury, 130 (12%) led to long-term symptoms according to that definition. Calculation of relative injury risk - According to Evans (1986), when two cars collide with each other, the injury risk for Car 1 in relation to Car 2 can be expressed as the number of injured occupants in Car 1 in relation to the number in Car 2. This is equal to the risk of injury in Car 1 in relation to the risk of injury in Car 2, which can be denoted as p1/p2. Assuming that the probabilities p1 and p2 are independent, and that the injury risk in Car 2 can be expressed as the injury risk in Car 1 multiplied by a constant, four cases can be summed: x1, x2, x3 and x4. The relative injury risk in the whole range of impact severity is equal to equation (1). In this study the relative injury risk for the sum of all cars in each group studied was calculated. In a similar way the relative risk of injury in rear-end crashes can be calculated with the same technique, where the number of crashes with injured drivers in the struck car in rear-end crashes in relation to the number of crashes with injured drivers in the striking car are summed, see Table 1. The method used in this study to calculate relative injury risk has been further described by Hägg et al. (1992) and Hägg et al (1999). The initially presented method is relevant for cars of similar mass. If Car 1 and Car 2 have unequal mass, the exposure to impact severity will be unequal as well. While crashworthiness rating based on real-life experience should preferably show the benefit or dis-benefit of mass, the current method would give too much attention to mass, as it would also include the benefit or dis-benefit for the colliding partner. When calculating the injury risk for car models relative to the average car, it is important that the relative injury risk for all car models can be compared with the identical average car. This is not the case if the influence of mass differences on the exposure for the collision partner is not compensated. The initial estimate, equation (1), must therefore be modified to take mass relations into account. The factor m was calculated for the car models in each group under study, and thus used to compensate the relative injury risk for the models in each group, see equation (2).

220 IRCOBI Conference - Maastricht (The Netherlands) - September 2 007 Table 1. Classification of combinations of injured drivers in the struck and striking car in rear- end crashes. Drivers in the striking car Total Driver not driver injured injured driver Drivers X x x+ x injured 1 2 1 2 in the driver struck not X x car 3 4 injured Total x1+ x3

x1 = number of crashes with injured drivers in both cars x2 = number of crashes with injured drivers in struck car and not in the striking car x3= number of crashes with injured drivers in striking car and not in struck car x4= number of crashes without injured drivers in both cars

R = (x1 + x2) / (x1 + x3) (1). ((M-Maverage)/100) Rmodified = R*m = ((M-Maverage)/100) = (x1 + x2) / (x1 + x3) *m (2).

M is the mass of the studied vehicle and Maverage is the average mass of all vehicles. In these calculations the factor m was set as 1.035, see Hägg et al. (1992), which mean that the mass effect used to control for the exposure on impact severity was 3.5% per 100 kg. The relative risk of sustaining an injury with long-term symptom was calculated as the product of the relative injury risk and the proportion of occupants with long-term symptoms in relation to the number of reported whiplash injuries (no symptom length constraint). Categories of cars studied - The reported whiplash injury (no symptom length limit) and long-term injury (1 months as defined above) risks were calculated for some different categories with and without whiplash protection system as described in Table 2. Note that in the /V70 model WHIPS was introduced in May 1999. Because it was not possible to identify whether these cars in real-life crashes were fitted with WHIPS or not, this model year was excluded in the analysis.

Table 2. Car models included in the defined groups. Saab w/o Saab with Toyota w/o Toyota with Volvo w/o Volvo with SAHR SAHR WIL WIL Whips Whips Saab 9000, Saab 9-5, 98- Starlet, 97-99 Yaris, 99-05 S40/V40, 96- S40/V40, 00- 85-97 99 03 Saab 900, 94- Saab 9-3, 98- Corolla, 98- Corolla, 02- 850 S40/V50, 04- 97 02 02 06 Saab 9-3, 03- Avensis, 98- Avensis, 03- S70/V70, 97- S70/V70, 00 02 98 Camry, 92-00 Camry, 01- V70, 00- RAV4, 95-99 Prius, 01- S60, 99- RAV4, 00- S80, 98- Corolla Verso, 04-

DYNAMIC RATING PERFORMANCE - A series of seat sled tests were performed according to the most recent SRA (Swedish Road Administration)/Folksam seat performance rating (Folksam) which was harmonized with the IIWPG (International Insurance Whiplash Protection Group) rating procedure. That is in short, tests with a BioRID seated in a seat according to a standardized positioning procedure. The fore-aft seat and the headrest positions were adjusted to the mid-positions. The pulses

IRCOBI Conference - Maastricht (The Netherlands) - September 2 007 221 used were the low risk-high injury frequency at 16 km/h in v and 4.5g in average acceleration, the median risk-median injury frequency 16 km/h/5.5g (10g peak) and the high risk-low injury frequency 24 km/h/6.5g all shown in the appendix. The injury parameters measured and calculated were the combination of the previous SRA/Folksam and IIWPG parameters, NIC, Nkm, rebound, T1 acc/head- to-headrest contact time, upper neck Fx and Fz. Using the 70th percentile value of 31 rated seats of model year 2006-7 published by SRA/Folksam, ADAC and partly by Thatcham (SRA, Folksam, ADAC, Thatcham) all resulting parameters were normalized. The 70th and 5th percentile values of the 31 seats are shown in the appendix. The seats tested were used ones from Saab and Volvo car models just before and after the SAHR and Whips introduction. Also, seats from Toyota Corolla without WIL were tested. Published rating tests of Toyota Avensis with WIL and the most recent versions of seats with SAHR, Whips and WIL were included in the analysis. The seats used in the dynamic rating evaluation are shown in Table 3. For the most recent versions of seats designed with SAHR, Whips and WIL, a combined rating evaluation was performed according to the latest SRA/Folksam procedure. In short, this procedure gives points on a sliding scale between the 5th and 70th percentile values of the recently tested 31 seats. That means that values above the 70th percentile value result in zero score points and values below the 5th percentile value results in maximum score points. The scoring points of the NIC, Nkm, rebound, T1 acc/head-to-headrest contact time, upper neck Fx and Fz parameters are summed up to a single value for all three pulses. No modifiers were used.

Table 3. The seats evaluated in the dynamic rating evaluation and their corresponding model year, anti-whiplash function and initial backset (pre-test BioRID head-to-headrest distance according to the procedure used in the rating tests)

Car model Model year Anti-whiplash Initial backset function [cm] Saab 900 94-97 No 30 Saab 9-3 98-02 SAHR 75 Saab 9-3** 03- SAHR 60 97-98 No 75 Volvo V70 99-00 WHIPS 40 ** 07- WHIPS 25 Toyota Corolla 93-97 No NA Toyota Avensis* 03- WIL 75 Toyota Prius** 01- WIL 65 *Published test results by Folksam/SRA year *2004 and **2006 respectively.

RESULTS REAL LIFE PERFORMANCE - The redesign of the Saab, Volvo and Toyota cars resulted in a 50- 71% risk reduction of long-term injuries as defined in the method section. The relative long-term injury risk figures for these car makes/models with and without anti-whiplash design are shown in Figure 1. The combined risk figures and number of long-term injuries, reported injuries (non-specified length of symptom) and crashes for Saab, Volvo and Toyota car models with and without anti- whiplash design are shown in Table 4. In the appendix, all figures used in the calculations (equation 1 and 2) as well as the risk figures and number of long term injuries and reported injuries for each Saab, Volvo and Toyota model included in the analysis are shown.

222 IRCOBI Conference - Maastricht (The Netherlands) - September 2 007 Table 4. Long-term injury risk reduction for Volvo, Saab and Toyota seats with and without anti-whiplash design. Also, the number of long-term and reported injuries and crashes as well as risk of long-term and relative risk of long-term and reported injury are shown.

Number Number Risk of Number Relative Relative Reduction of long- of long-term of crashes reported long-term term reported injuries injury risk injuries injuries risk Volvo w/o 26 177 14,7% 944 1,02 0,150 Whips Volvo with 8 107 7,5% 617 1,00 0,075 50% Whips

Saab w/o 28 167 16,8% 483 1,10 0,184 SAHR Saab with 6 114 5,3% 340 1,02 0,054 71% SAHR

Toyota w/o 43 311 13,8% 136 1,41 0,195 WIL Toyota 19 235 8,1% 110 1,17 0,095 51% with WIL

0,2

0,15

Volvo 0,1 Saab Toyota

0,05

0 w/o anti-whiplash design with anti-whiplash design

Figure 1 - Relative long-term injury risk for Volvo, Saab and Toyota cars with and without anti-whiplash seat design.

DYNAMIC RATING PERFORMANCE - All normalized (with respect to a 70th percentile value according to the method section) evaluation values are shown in Figures 2-10. The combined scores, as described in the method section, for all analyzed seats in this study are presented in Figure 11. Note that the maximum score for each pulse was 3 points.

IRCOBI Conference - Maastricht (The Netherlands) - September 2 007 223 Low pulse SAHR

2 1,8 Before SAHR 1,6 redesign 1,4 After SAHR 1,2 redesign 1 Saab 9-3 [06] 0,8 0,6 70thpercentile 0,4 0,2 0

m Fx Fz nd NIC k u N o b e R Min(T1/HCT)

Medium pulse SAHR

2 1,8 Before SAHR 1,6 redesign 1,4 After SAHR 1,2 redesign 1 Saab 9-3 [06] 0,8 0,6 0,4 70thpercentile 0,2 0

m k T) Fx Fz nd NIC N C u /H o 1 eb R in(T M High pulse SAHR

2 1,8 Before SAHR 1,6 redesign 1,4 After SAHR 1,2 redesign 1 Saab 9-3 [06] 0,8 0,6 0,4 70thpercentile 0,2 0

) d T Fx Fz NIC km C N oun /H b 1 e (T R Min Figure 2-4 – Normalized (to 70 percentile values of the 31 seats) rating parameter values for Saab seats with and without SAHR system

224 IRCOBI Conference - Maastricht (The Netherlands) - September 2 007 Low pulse WHIPS

2 1,8 Before Whips redesign 1,6 1,4 After Whips 1,2 redesign 1 0,8 Volvo S80 [07] 0,6 0,4 0,2 70thpercentile 0

C m z k Fx F NI N CT) /H 1 ebound (T R in M

Medium pulse WHIPS

2 Before Whips 1,8 redesign 1,6 1,4 After Whips 1,2 redesign 1 0,8 Volvo S80 [07] 0,6 0,4 0,2 70thpercentile 0

z km T) Fx F NIC N ebound (T1/HC R n Mi

High pulse WHIPS Before Whips redesign 2 1,8 1,6 After Whips redesign 1,4 1,2 1 Volvo S80 [07] 0,8 0,6 0,4 70thpercentile 0,2 0

m Fx Fz nd NIC Nk CT) u /H bo e R in(T1 M Figure 5-7 – Normalized (to 70 percentile values of the 31 seats) rating parameter values for Volvo seats with and without Whips system

IRCOBI Conference - Maastricht (The Netherlands) - September 2 007 225 Low pulse WIL

2 1,8 Toyota 1,6 Corolla [93] 1,4 Toyota 1,2 Avensis [04] 1 0,8 Toyota Prius 0,6 [06] 0,4 70th 0,2 percentile 0

) m T Fx Fz nd NIC k u N o 1/HC b (T Re Min

Medium pulse WIL

2 1,8 Toyota 1,6 Corolla [93] 1,4 1,2 Toyota Avensis [04] 1 0,8 Toyota Prius 0,6 [06] 0,4 0,2 70th 0 percentile

x C m T) F Fz NI Nk /HC 1 ebound (T R n Mi High pulse WIL

2 1,8 Toyota Corolla 1,6 [93] 1,4 Toyota Avensis 1,2 [04] 1 0,8 Toyota Prius 0,6 [06] 0,4 70th percentile 0,2 0

m x z k F F NIC N /HCT) 1 Rebound Min(T Figure 8-10 – Normalized (to 70 percentile values of the 31 seats) rating parameter values for Toyota seats with and without WIL system. The Nkm and Fx values in the high pulse (out of range in the diagram) were 2.57 and 1053 N respectively.

226 IRCOBI Conference - Maastricht (The Netherlands) - September 2 007 3,0

2,5

2,0 Low pulse 1,5 Medium pulse High pulse 1,0

0,5

0,0 Saab 9-3, 06 Volvo S80, 07 Toyota Prius, 06 Average 31 seats

Figure 11 – The combined scores for the most recent versions of seats designed with SAHR, Whips and WIL systems. 3 points is the best score possible for each pulse. The Prius high pulse score was 0 points.

DISCUSSIONS The time period of 1 month for whiplash symptoms used in this study was chosen because it takes several years, sometimes up to 6 years, until a degree of permanent disability can be finally set and verified according to the system used by the insurance companies in Sweden. To be able to evaluate permanent disability crashes older than 6 years can only be used, which is not applicable to study whiplash preventive systems introduced the latest 6 years. The ratio of number of cars on the roads with seats designed with and without anti-whiplash designs increases of natural reasons. If insurance claims increases over time even for the same car model, the used risk evaluation is less valid. Therefore, the stability of long-term injury risk over the years was investigated. In Figure 12, the rates of reported injuries from cars with model year 85-98 with pay-out above 500/1000/1500 and 2000 SEK (about 75/150/225 and 300 US$) during the years 1999-2004 are shown. While the rates based on cash pay-outs of 500 SEK slightly increased from year 1999 to 2004, this was not the case for the 2000 SEK limit which was used in the report.

IRCOBI Conference - Maastricht (The Netherlands) - September 2 007 227

r-500 r-1000 r-1500 r-2000 0,7

0,6

0,5

0,4

0,3

0,2

0,1

0 1999 2000 2001 2002 2003 2004 Accident year Figure 12 – Rate of long-term reported injuries from cars with model year 85-98 with pay-out above 500/1000/1500 and 2000 SEK during the years 1999-2004. The figure shows that the r- 2000 (used in this study) rates do not increase over the years.

In addition to the dynamic tests of seats with and without anti-whiplash designs, tests were performed with blocked WHIPS and SAHR functions (that is welding of the yielding recliner and the moving headrest respectively). Volvo seats with WHIPS, however with headrests moved rearward achieving a head-to-headrest distance of 70 mm, were also tested. While blocking of the yielding recliner resulted in rating performance similar to seats without a yielding recliner, blocking of the headrest in the Saab seats did not alter much the dynamic performance. Also, moving the headrest rearward in the WHIPS seats did not alter the dynamic performance to any great extent. It seems as the yielding recliner of the WHIPS system is robust in the sense of increased backset and that the protective effect of Saab-SAHR seats is not only due to a moving headrest. Adding to this the fact that the non SAHR Saab seats had a backset of 30 mm (Table 3) and the shown protective effect of yielding seat attachment brackets in seats with poor headrest geometry (Krafft et al, 2004), low head- to-headrest backset (< 30mm) is not a guarantee, nor necessary, for good real-life or rating performance. In general all rating parameters if not already low were reduced considerably for the anti-whiplash designed seats under the low and medium severity conditions. For the high severity pulse the reductions were not as consistent. For the WIL designed seat the rating performance was actually worse. Although the high severity pulse may be useful from a consumer perspective, a good or bad performance for this severity may not affect the overall real-life performance.

CONCLUSIONS According to the real-life study in this paper, the SAHR, WHIPS and WIL redesigns reduced the risk of long-term injury, defined as when an occupant claimed injury symptoms for more than 1 month, considerably (50-70%). The dynamic rating analysis of the redesigns showed a considerable performance improvement. As a conclusion, characteristics of good performing seats found in this study were good performance in dynamic rating tests, especially for the low and medium severity pulses, through designs aimed at reducing head-to-head restraint distance and yielding/energy absorption of the seat.

228 IRCOBI Conference - Maastricht (The Netherlands) - September 2 007 REFERENCES

ADAC website: www.adac.de Evans L (1986) Double pair comparison – a new method to determine how occupant characteristics affect fatality risk in traffic crashes. Accid. Anal. and Prev., Vol. 18, No. 3:pp 217-227 Folksam website: www.folksam.se/forskning/index.htm, see ”Whiplash” Hägg A, v Koch M, Kullgren A, Lie A, Nygren Å, Tingvall C (1992) Folksam Car Model Safety Rating 1991-92, Folksam Research 106 60, Stockholm, Sweden Hägg A, Krafft M, Kullgren A, Lie A, Malm S, Tingvall C, Ydenius A (1999) Folksam Car Model Safety Ratings 1999, Folksam Research 106 60, Stockholm, Sweden IIHS website: www.iihs.org Jakobsson L. Whiplash Associated Disorders in Frontal and Rear-End Car Impacts. Biomechanical. Thesis for the degree o doctor of philosophy. Crash Safety Dividson , Dep of Machine and Vehicle Systems. Chalmers University of Technology, Sweden 2004 Kraftt M (1998) Non-Fatal Injuries to Car Occupants - Injury assessment and analysis of impacts causing short- and long-term consequences with special reference to neck injuries, Thesis, Karolinska Institutet, Stockholm, Sweden Krafft M, Kullgren A, Lie A, Tingvall C (2003) Utvärdering av whiplashskydd vid påkörning bakifrån – verkliga olyckor och krockprov. (“Evaluation of whiplshprotection systems in rear-end collisions – real-life crashes and crash tests”). Folksam and SRA, Folksam research 10660 Stockholm, Sweden Krafft M, Kullgren A, Ydenius A, Boström O, Håland Y, Tingvall C (2004) Rear impact neck protection by reducing occupant forward acceleration – A study of cars on swedish roads equipped with crash recorders and a new anti-whiplash device. Proc. of the IRCOBI Conf. on the Biomechanics of Impacts Kullgren A, Eriksson L, Boström O, Krafft M (2003) Validation of neck injury criteria using reconstructed real-life rear-end crashes with recorded crash pulses. Proc. of the 18th Techn. Conf. on ESV, Paper No. 344, Tokyo, Japan Kullgren A, Krafft M, Lie A, Tingvall C (2007) The Effect of Whiplash Protection Systems in Real-Life Crashes and Their Correlation to Consumer Crash Test Programmes, Proc. of the ESV Conf. 2007, Paper No.07- 0468, Lyon, France Lundell B, Jakobson L, Alfredsson B, Lindström M, Simonsson L (1998) The WHIPS seat – A car seat for improved protection against neck injuries in rear end impacts. Paper No 98-S7-O-08, Proc. 16th ESV Conf, 1998, pp. 1586-1596 Nygren Å, Gustavsson H, Tingvall C (1985) Effects of Different Types of Headrests in Rear-end Collisions. Proc. of the 9th ESV conf. Oxford, UK. pp85-90 Sekizuka M (1998) Seat Designs for Whiplash Injury Lessening, Proc. 16th Int. Techn. Conf. on ESV, Windsor, Canada SRA (Swedish National Road Administration) website: www.vv.se Thatcham website: www.thatcham.org Viano D and Olsen S (2001) The Effectiveness of Active Head Restraint in Preventing Whiplash. The Journal of TRAUMA Vol 51:pp959-969 Wiklund K, Larsson H (1997) SAAB Active Head Restraint (SAHR) - Seat Design to Reduce the Risk of Neck Injuries in Rear Impacts, SAE Paper 980297, Warrendale

IRCOBI Conference - Maastricht (The Netherlands) - September 2 007 229 APPENDIX

10 Low Medium 8 High

6

4 Acceleration (g)

2

0 0 20 40 60 80 100 120 Time (ms)

Figure 1 – Schematic description of the three pulses used in the seat rating.

Table 1. All 5 and 70 percentile values from the rating test series of the 31 seats (model year 2006-7)

NIC Nkm T1 HCT Fx Fz Rebound [m^2/s^2] [g] [ms] [N] [N] [m/s] Low pulse 5% values 9 0,12 9,4 55 30 270 3 70% values 15 0,35 12 77 110 610 4,4 Medium pulse 5% values 11 0,15 9,3 51 30 360 3,2 70% values 24 0,55 13,1 76 190 750 4,8 High pulse 5% values 13 0,22 12,5 48 30 470 4,1 70% values 23 0,47 15,9 75 210 770 5,5

230 IRCOBI Conference - Maastricht (The Netherlands) - September 2 007 Table 2. Number of long-term and reported injuries as well as risk of long-term injury for each model used in the real life performance study.

Number of Number occupants of Risk of with long- reported long- term whiplash term Make injuries injuries injury /V40 96-99 12 73 16,4% Volvo S40/V40 00-03 3 39 7,7% Volvo S40/V50 04- 0 2 0,0% 7 68 10,3% Volvo S70/V70 97-98 7 36 19,4% Volvo S70/V70 99 3 19 15,8% Volvo S70/V70 00 2 18 11,1% Volvo V70E 00- 1 23 4,3% 1 11 9,1% Volvo S80 1 14 7,1% Volvo without Whips 26 177 14,7% Volvo with Whips 8 107 7,5%

Saab 900 94- 16 83 19,3% Saab 9-3 98-02 2 51 3,9% Saab 9-3 03- 1 2 50,0% Saab 9000 12 84 14,3% Saab 9-5 3 61 4,9% Saab without SAHR 28 167 16,8% Saab with SAHR 6 114 5,3%

Toyota Yaris 99- 10 82 12,2% Toyota Corolla 02- 6 75 8,0% Toyota Corolla Verso 1 9 11,1% Toyota RAV4 00- 1 32 3,1% Toyota Avensis 03- 1 31 3,2% Toyota Camry 01- 0 6 0,0% Toyota Starlet 97-99 2 25 8,0% Toyota Corolla 98-02 7 75 9,3% Toyota Avensis 98-02 16 99 16,2% Toyota Camry 92-00 16 93 17,2% Toyota RAV4 95-99 2 19 10,5% Toyota without WIL 43 311 13,8% Toyota with WIL 19 235 8,1%

IRCOBI Conference - Maastricht (The Netherlands) - September 2 007 231 Table 3. All figures used in the calculations (equation 1 and 2) of the risk figures.

No. Model crashes X1 X2 X3 R M Rmodified SAAB 900 94- 128 30 63 44 1,260 1,035 1,30 SAAB 9-3 98- 97 33 30 30 1,000 1,046 1,05 SAAB 9-3 03- 42 18 19 12 1,230 1,077 1,32 SAAB 9000 85-97 355 94 147 148 1,000 1,043 1,04 SAAB 9-5 98- 201 66 65 91 0,830 1,131 0,94 TOYOTA AVENSIS 98- 37 6 22 12 1,556 1,029 1,60 TOYOTA AVENSIS 03- 10 2 6 1 2,667 1,040 2,77 TOYOTA CAMRY 92- 96 32 8 12 15 0,870 1,061 0,92 TOYOTA CAMRY 97- 9 6 3 0 1,500 1,075 1,61 TOYOTA CAMRY 01- 3 1 2 1 1,500 1,084 1,63 TOYOTA COROLLA 98- 45 10 33 9 2,263 0,979 2,22 TOYOTA COROLLA 02- 31 19 9 8 1,038 0,993 1,03 TOYOTA PRIUS 04- 1 1 0 0 1,000 1,027 1,03 TOYOTA RAV4 95-99 13 4 7 7 1,000 1,019 1,02 TOYOTA RAV4 00-04 14 3 5 3 1,333 1,049 1,40 TOYOTA STARLET 97- 6 1 2 4 0,600 0,902 0,54 TOYOTA YARIS 99- 51 15 24 18 1,261 0,909 1,15 VOLVO 800 437 137 178 175 1,010 1,068 1,08 VOLVO S40 V40 1996- 1999 161 47 73 59 1,130 1,016 1,15 VOLVO S40 V40 2000- 2003 190 44 95 66 1,260 1,016 1,28 VOLVO S60 75 17 22 36 0,740 1,088 0,81 VOLVO S70 V70 97-00 346 91 112 155 0,830 1,083 0,90 VOLVO S80 78 21 28 33 0,907 1,110 1,01 VOLVO V70E 00- 274 75 87 131 0,786 1,127 0,89 Volvo Whips 617 157 232 266 0,920 1,086 1,00 Volvo without Whips 944 275 363 389 0,961 1,065 1,02 Saab SAHR 340 117 114 133 0,924 1,100 1,02 Saaab without SAHR 483 124 210 192 1,057 1,041 1,10 Toyota WIL 110 41 46 31 1,208 0,968 1,17 Toyota without WIL 136 34 77 43 1,390 1,017 1,41

232 IRCOBI Conference - Maastricht (The Netherlands) - September 2 007