ISOFIX : Parents testing three different systems of child seat attachment

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VTl meddelande

Nr 688A - 1992

ISOFIX

Parents testing three different systems of child seat attachment

Hans-Y¥ngve Berg och Nils Petter Gregersen

Vag-och

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VTI meddelande

Nr 688A - 1992

ISOFIX

Parents testing three different systems of child seat attachment

Hans-Yngve Berg och Nils Petter Gregersen

as

v

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Publisher: Publication: VTI h/IEDDELANDE 688A

ublished: Project code: 1992 56485-6

Swedish Roadand _ Project

M Traffic ResearchInstitute ISOFIX Swedish Road and Traffic Research Institute e $-581 01 LinkGping Sweden

Author: Sponsor:

Hans-Yngve Berg och Nils Petter Gregersen Swedish Road Safety Office

Title:

ISOFIX - Parents testing three different systems of child seat attachment

Abstract (background, aims, methods, results) max 200 words:

A great and common problem when using child restraints is misuse, i.e. incorrect mounting. The normally very high safety effect is then drastically reduced.

In order to handle these problems of incorrect mounting, AUTOLIV, FOLKSAM, SAAB, VOLVO and VTI (the Swedish Road and Traffic Research Institute) have developed two new fastening devices designed to minimize incorrect mounting. In the project phase, these two new systems are called ISOFIX and DELTAFIX.

The two new systems are based on the principle that the fastening elements for child seats are already mounted in the car when delivered. New attachments fitting one of the two new systems shall also be integrated in the child seat at purchase.

The aim of the project is to study the simplicity of mounting/demounting, possible misuse as well as views, ideas and assessments by parents of small children concerning these three different fastening devices.

The study was carried out through observational studies and interviews of 46 parents of small children when they had tested the two new systems and the conventional system with fastening straps and seat belts. Furthermore, the subjects had to fill in a questionnaire.

The result shows that the two new FIX systems minimize incorrect mounting and that the usual system shows a very high percentage of misuse. Parents of small children are also in favour of the new systems and 89% are willing to pay a fairly large amount of money to have the systems mounted in their cars.

The subjects rank the ISOFIX system highest when it comes to simplicity of use. The DELTAFIX system is ranked highest when it comes to safety and stability. The conventional system is ranked lowest in all questions concerning order of preference.

Keywords:

ISSN: Language: , No. ofpages:

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Preface

This study was made possible thanks to funds granted by the National Road Safety Office for Swedish work in the field of the European working group ISO/TC 22/SC 12WG1 "Child Restraint Systems in Road Vehicles".

Thomas Turbell is the head of a project for the design of the so-called FIX systems at the Swedish Road and Traffic Research Institute.

Hans-Y¥ngve Berg and Nils Petter Gregersen were responsible for the planning and execution of this study and the design of the questionnaire. Special thanks to Inger Bengtsson and Maria Olausson who assisted in the carrying out of the study.

Finally, we are much obliged to Ann-Sofie Senneberg, responsible for the layout of the report and also to Christina Ruthger responsible for the translation into English.

We also wish to direct our thanks to Volvo for providing cars in which the new Fix anchorages were installed and to Autoliv for lending a car child seat fitted with their DELTAFIX anchorage.

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CONTENTS

Page

SUMMARY I

1 BACKGROUND AND AIM 1

2 METHOD 2

3 RESULTS 3

3.1 General description of the test group 3 3.2 Mounting and demounting, research leader's assessment 6 3.3 Personal assessments of respective child seat 7 3.4 How did subjects answer the interview questions? 14 3.5 Subjects' rankings of the three systems 21

4 DISCUSSION 25

4.1 Discussion of Methods 235

4.2 Discussion of Results 26

3 PROPOSAL FOR FUTURE RESEARCH 28

6 REFERENCES 29

Appendix 1 Mounting instruction: ISOFIX, DELTAFIX (3 pages) and CONVENTIONAL SEAT

Appendix 2 Questions posed before subjects had mounted any (1 page) of the child seats

Appendix 3 The protocol of the research leader (1 page) Appendix 4 Reply card: ISOFIX, DELTAFIX and (6 pages)

CONVENTIONAL SEAT

Appendix 5 Questions after testing one of the systems (2 pages) Appendix 6 Questions after testing all the systems (2 pages) Appendix 7 Fix test order scheme (1 page) Appendix 8 Instruction to subjects (1 page) Appendix 9 Status report about ISOFIX to GRSP (6 pages)

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SUMMARY

A great and common problem when using child restraints is misuse, i.e. incorrect mounting. The normally very high safety effect is then drastically reduced.

In order to handle these problems of incorrect mounting, AUTOLIV, FOLKSAM, SAAB, VOLVO and VTI (the Swedish Road and Traffic Research Institute) have developed two new fastening devices designed to minimize incorrect mounting. In the project phase, these two new systems are called ISOFIX and DELTAFIX.

The two new systems are based on the principle that the fastening elements for child seats are already mounted in the car when delivered. New attachments fitting one of the two new systems shall also be integrated in the child seat at purchase.

The aim of the project is to study the simplicity of mounting/demounting, possible misuse as well as views, ideas and assessments by parents of small children concerning these three different fastening devices.

The study was carried out through observational studies and interviews of 46 parents of small children when they had tested the two new systems and the ordinary system with fastening straps and seat belts. Furthermore, the subjects had to fill in a questionnaire.

The result shows that the two new FIX systems minimize incorrect mounting and that the usual system shows a very high percentage of misuse. Parents of small children are also in favour of the new systems and 89% are willing to pay a fairly large amount of money to have the systems mounted in their cars.

The subjects rank the ISOFIX system highest when it comes to simplicity of use. The DELTAFIX system is ranked highest when it comes to safety and stability. The conventional system is ranked lowest in all questions concerning order of preference.

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1 BACKGROUND AND AIM

A recurring problem when using child restraints is incorrect mounting to the vehicle structure. The normally very high safety effect of child restraints is drastically reduced, with severe consequences in the event of an accident.

In order to handle these problems of incorrect mounting, AUTOLIV, FOLKSAM, SAAB, VOLVO and VTI (the Swedish Road and Traffic Research Institute) have developed two new fastening devices designed to minimize incorrect mounting, thus preventing a worse situation for the child in the event of an accident. In the project phase, these two new systems are called ISOFIX and DELTAFIX (see Appendix 1).

The two new systems are based on the principle that the fastening elements for child seats are already mounted in the car when delivered. New attachments fitting one of the two new systems must also be integrated in the child seat at purchase. The future aim is that one of these two new systems will be mounted in every car when leaving the factory. A uniform standard for the fastening of child restraints will then be obtained for all makes of cars.

The question is whether these two new systems simplify the procedures of fastening and unfastening child restraints and what attitudes do parents of small children have to these new systems compared with the ordinary system with fastening straps and seat belt use. Thanks to funds granted by the National Road Safety Office, the VTI was given the opportunity to carry out a study to elucidate these important matters.

In the light of these facts, the VTI carried out a project with the aim of studying the simplicity of mounting/demounting and possible misuse, as well as views, ideas and assessments by parents of small children concerning the three different fastening devices.

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2 METHOD

The target group of the study was parents who had used rearward facing child seats for the last five years. The target group is not a representative sample of the population in Sweden as parents of small children have not been randomly chosen to participate in the experiment, but invited through personal contacts. None of the subjects was informed in advance of the purpose of the experiment. None of the parents had seen any of the systems in real life, but one person had seen an article in the press. The requirement for a couple to participate in the test was that they turned up at the same time, thus preventing either of them from explaining the design of the test to the other. Each person had to test the fastening device on his/her own with no help from anyone else.

Prior to testing any of the systems, parents had to fill in a page in a questionnaire concerning their background (see Appendix 2). Having answered these questions, they were directed to a research leader who asked them to read the instructions on installation (see Appendix 1) for each system and helped them to get started with the child seat testing. The research leader recorded the subjects' ability to mount and demount the three different seats (see Appendix 3). The three systems were installed in three cars parked in the vehicle hall at the Institute. The test vehicles were arranged so as not to be seen from one another, thus preventing the subjects from obtaining any help from other parents. Parents tested one of the systems and then filled in a reply card with fixed alternatives (see Appendix 4). Having answered a certain number of questions on the reply card, the subject was requested to stop (this was written on the reply card) in order to be interviewed by the research leader. This procedure, answering a reply card and interview questions (see Appendix 5), was repeated when the subject had tested each system three times in all. When all three systems had been answered, the subjects had to answer still another questionnaire where the three systems were to be ranked from different aspects (see Appendix 6). In order to prevent learning effects from influencing the result, subjects had to start testing the different systems according to a fixed scheme (see Appendix 7). The subjects' ways of handling the new systems when mounting and demounting the seats were also recorded on video. A total of 46 subjects tested the three different systems.

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3 - RESULTS

The results are presented in five different sections, where the first section deals with subjects' answers to the background questions.

The second section describes how respondents coped with the different systems according to the research leader.

The third section reports how subjects answered the fixed alternatives of the different reply cards.

The answers to different interview questions posed on the same occasion as respondents filled in the reply card are reported in the fourth section.

Finally, respondents' answers to the last questionnaire where they had to rank the different systems are reported.

3.1 General description of the test group

The test group consisted of 46 persons in all, 23 men and 23 women. The age distribution of subjects is given in Figure 1.

[I Women G# Men J Number of subjects \V ades DJ pos ses G G a 'ad I SA X Ko . NSSY ] v4 .00 .0 ad 's «-h o o t t a m i GonKe n K e n SennKo ne -C -[XX SC S~3 3C~ T5T Ca d WN SN A D Y P M e d x _ xx QJ @ @ Un U 32 55 5+ 5? ~5 1g 55 u9 u - U CO 31 41 _ 43 24 -26 28 30 32 34 -36 -38 40 42 -44 Age ID J U G Ne , U n (N e) s q D o ( O

Figure 1 Age distribution of subjects according togender

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91.3% (i.e. 42) of the 46 subjects had a driving licence. Three of the four subjects who did not have a licence (8.7%) were women.

Figure 2 shows that the respondents had one to four children. The majority had one or two children.

Number of subjects 25 20 15 10 i th th th C to t h to Th Th Tb 3 R R RC R RO R RO R k . . i _> :® 1 2 "3 4 Number of children

Figure 2 How many children did the respondents have?

The age of the children varied from one year up to 19 years; age distribution is given in Figure 3. All respondents have one child or more aged 5 or younger.

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Number of children 20 15 10 | -1 3 S 7 9 11 a 4 6 8 10 12 Age

Figure 3 Age distribution of children

In order to obtain some measure of parents' experience of handling child seats, a question was posed regarding the number of seats they had used. Only rearward facing seats were included. According to the result in Figure 4, most respondents had used more than one child seat, the majority two or three seats.

Number of subjects 20

Number of used childseats

Figure 4 The number of child seats used by each subject

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3.2 Mounting and demounting, research leader's assessment

Figure 5 shows the subjects' ability to mount (fasten) the three child seats in the front seat. The result shows that the conventional seat caused most problems. Only a few subjects failed in understanding the idea of the FIX systems.

E CONVENTIONAL DELTAFIX EX ISOF IX | % 100 80 60 40 20 _{Cs & SSC} 0.0 .0. 0, @ 0.0 .0. 0, (X) < » Ses ese s 0 :

No problems Some hesitation Help needed Fail Wrong install.

Figure 5 Mounting of child seats

Figure 6 shows subjects' ability to demount (unfasten) the three child seats. This activity caused fewer problems as subjects had learnt the principles through mounting the seat before demounting it.

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|Es CONVENTIONAL DELTAFIX Ea ISOFIX _ % 100 80 40 20 R N _R . u w w l b3 » ___A ___A ___A _ _ ¥ ° N NR &_ a U a a U ce PAA Z

No problem Some hesitation Help needed Fail

Figure 6 Demounting of child seats

3.3 Personal assessments of respective child seat

In order to mount a child seat correctly, instructions should be easy to understand. The instruction, together with the design of the fastening device, should be self-instructional. To find out the respondents' opinion of the three instructions, they had to answer the question "Do you find the instruction for the seat easy or difficult to understand?". The question had five fixed response alternatives. The response alternatives and subjects' answers to the question can be concluded from Figure 7. As regards the conventional system, subjects are divided in their opinions. The new systems are mainly found very easy or easy and only a few found the FIX instructions difficult or very difficult to understand.

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[Eas CONVENTIONAL & DELTAFIX E3 ISOFIX | % 100 80 60 40 [ 20 A A 30 } A U a

Figure 7 Assessment of instructions for the different seats

One question that can be asked when an instruction is to be formulated is whether the instruction should emphasize the mounting or demounting of the child seat. To solve this problem, the following question was to be answered "Was the instruction of great or little use when mounting or demounting the seat?". The question was divided so the respondent had to state the use of the instruction when fastening the seat and the use when unfastening the seat. The answers to the two part questions and the response alternatives are given in Figures 8 and 9.

The result shows that all subjects experienced that the instruction was of no help when fastening the ordinary conventional seat, but of great or considerable help when fastening the seat with the FIX systems. When demounting the three seats, the majority of subjects felt that they had only little or no help from instructions. This result shows that when producing an instruction, stress should be laid on the mounting of the child seats as, according to respondents, most help and guidance is needed in this particular activity.

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9 [E CONVENTIONAL E 3 DELTAFIX Ea IsoF IX I % 100 80 60

Very great use Great use Little use No use

Figure 8 Was the instruction of great or little use when fastening the seat?

| EE] CONVENTIONAL DELTAFIX E3 ISOFIX | % 100 80 60 o 3 a 0 C O " l ' i v l v l n ; i ; l v c l t v c l : >C0b 40 C ce .6 : le te ! _& A X 0 0 ' 3 ¥ S o C0A" T &Cs SC & C s i$ _0°. & a®a$ c 20 _{be w}_{T @} & _@_{& tet}e₀0 as S S S 0 2 . se (AX C C0 . C X ) * o e s >C 0 A A_ A A R R R O N RL R NOO N O N OC N G C V BoXX X : oo a@s 4 O FS

Very great use Great use Little use No use

Figure 9 Was the instruction of great or little use when unfastening the seat?

A user-friendly child seat should be easy to fasten. The fastening of the seat

must not betoo difficult or require too many operations. The question "Did you

find that the child seat you just tested was easy or difficult to get into position?"

elucidates the subjects' assessments of each seat. The different response

alternatives and answers are shown in Figure 10. The result shows that the

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majority of respondents found the seats with the new FIX systems very easy or quite easy to get into position. However, some persons found the DELTAFIX seat hard to get into position. Approximately half the subjects found the conventional seat with fastening straps and seat belt easy to handle and approximately 40% found the conventional seat quite difficult or very difficult

to get into position.

'

| EEZ CONVENTIONAL

DELTAFIX

&3 ISOFIX

100 A

_{CR ol- d@}

& e

a SS

80 L

i

zo o * \ > @ Rete a & Xx 60 @ (X) ete! iA SS & te & se Se se se ate *

Very easy Neither easy or difficult Very difficult Rather easy Rather difficult

Figure 10 Did you find the child seat you just tested easy or difficult to get into position?

In order to prevent misuse of child seats, fastening devices of seats should be so simple and easy to understand that it will be obvious to users how the seat is to be fastened. This also concerns the demounting of seats. The respondents' assessments concerning obviousness when mounting and demounting the fastening devices are shown in Figures 11 and 12. These show that it is more obvious how to use the new FIX systems to fasten the child seat, but not more obvious than the conventional system concerning the understanding of how to dismount the child seat.

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VTI MEDDELANDE 688A

systems. The different response alternatives and answers are reported in Figure or difficult to remove the child seat?" reflects subjects' opinions of the different demounting of the seat even more difficult. The question "Did you find it easy complicated or comprise too many difficult operations and thus render the It should also be easy to demount a child seat. The attachment must not be too Figure 12 How obvious was the unfastening of the seat?

Very obvious Rather obvious Not obvious at all

NJ (n =I O (n O Cn 100 I l l f / I I I I / I I I A / l l l a D a he a n o n n n n m n n e I I I N X C C N e I X R el e -d o d o . C X O A X A \ L VL V V A Y 0 . 0 . 0 ¥0 ,0 .0 ,. 0, 0, .0 9. 0. 0. 0. 0. 1 =

| Es CONVENTIONAL DELTAFIX BX ISOFIX

Figure 11 How obvious was the fastening of the seat?

I o J & O C O O O O

Very obvious Rather obvious Not obvious at all

/ / / / / / A / / / / / / / / / / / A a U U a So k t S C N S N N N NC X X t h 0 0" 00 00 00 0 00 000, 0, 0. 0. 40 : C 0, 0. 0. 0. 0, © C 0, 0, .0 .0 .0.0 .0 .0 .0 .0 .9 -0 . X X A XA X M XX_ X _ I8 00 00 00N0 0 2 5C 5C 5C e 50 52 52 52 S2 Sp 00 00 00 00 00 0000 @ (O 0.0 . p n n n n X X X X n p l ll l l l l l l l l l l l l l l l l l l l l l l l

E CONVENTIONAL DELTAFIX BJ ISOFIX

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13. Almost all subjects experienced that it was very easy or quite easy to remove the seats. Only a few people experienced some difficulty in removing the seats.

EE CONVENTIONAL DELTAFIX 3 IsOoF IX % 100 15 50 25 & A A&A & A A i A s & & a U Very easy Neither easy or difficult Very difficult

Rather easy Rather difficult

Figure 13 Did you find it easy or difficult to remove the child seat?

The question "Do you find the seat stable?" was posed in order to find out how stable the attachment of seats was, according to subjects, and which system was most stable for fastening the seat in the front seat of the car. Figure 14 shows the different response alternatives for the question and the seat that was experienced as most stable in the front seat according to subjects. The new DELTAFIX system was experienced as the most stable system. The ISOFIX system was for the most part experienced as quite stable. The respondents' assessments of the conventional system varied from very stable to very unstable.

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|E CONVENTIONAL DELTAFIX && ISOFIX _ % 100 w . A _ _ a A 75 A _ a 3 A A 50 a A 25 _{> § So} 0! 3 % $ % 8 § So v 0 , c e !

P..

W

.

Very stable

Neither stable or unstable

Very unstable

Rather stable

Rather unstable

Figure 14 Do you find the seat stable?

If these new systems are to be spread widely, it is most important that parents of

small children conceive the fastening of the child seat with the systems as safe.

Consequently, the question "Do you consider the seat to be fastened in a safe

way?" was asked. The answers to the question and the respective response

alternatives are given in Figure 15. Many of the subjects experienced the

conventional system as quite safe. Principally, the two new FIX systems are,

however, experienced as very safe or quite safe.

[- CONVENTIONAL DELTAFIX 6x ISOFIX

% 100 " 7 [ : / 80_, f f ... so , A + " mor # *0[ > eese meres a 32 BSAC A ESX ... Pococs 20 poses r _Peete Leet XSS o L- _ 33

Very safe Neither safe or unsafe Very unsafe

Rather safe Rather unsafe

Figure 15 Do you consider the seat to be fastened in a safe way?

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3.4 How did subjects answer the interview questions?

The comments reported below are a list of all the comments to each interview question given by subjects. The subjects were asked the same four questions for each system (see Appendix 5). The questions were asked on the same occasion as subjects answered the reply card after testing a fastening device. The time the different questions were asked is noted on the reply card (see Appendix 4). The research leader asked the question and wrote down the answer on a reply form (see Appendix 5). The comments were then compiled, i.e. the comments that were similar were altered to somewhat more comprehensive comments, thus making them easier to grasp. The comprehensive comments are listed below.

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COMPREHENSIVE COMMENTS

Conventional seat

Was there anything that was particularly easy or difficult when fastening the

seat?

,

Difficult

_Easy

- To find the restraint anchorages of |- Ordinary simple seat belt

the fastening straps in the vehicle

attachments simplify use

chassis

- Fastening straps on the whole

- Vague instructions

ISOFTX

Was there anything that was particularly easy or difficult when fastening the

seat?

Difficult

Easy

- Difficult to understand where to

- Easy to put the seat in place as you

find the anchorages of the seat and

only had to press it on

how to unfold them

- Easy instruction

- Anchorages in place

- Only two restraint anchorages

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DELTAFTX

Was there anything that was particularly easy or difficult when fastening the seat?

Difficult _Easy

- Difficult to understand how to - Handy to use and easy to

fasten the upper anchorages understand how to use the lower anchorage

- Difficult to understand how to turn

the seat in order to attach the upper |- Simple and logical design thanks to

anchorages the fixed anchorages

- The upper fastening elements are |- Good, clear instruction stiff to handle

- Few operations when fastening the - Complicated/difficult instruction seat

- Difficult to understand how to use the lower anchorage and force is required to tighten it

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Conventional

Was there anything that was particularly easy or difficult when removing the seat?

Difficult _Easy

- Unfastening the fastening straps - Handy to use and easy with seat belt attachments

- Difficult and tiresome to unfasten

the strap towards the driver - Just to unfasten

- Many operations

- Poor instruction

ISOFIX

Difficult Easy

- Difficult to reach and needed - Just one operation, press two considerable force when pressing buttons and pull up the seat the red buttons

- Everything was well prepared. - Hard both to reach out and turn Easily accessible locking devices

one's back at the same time. Long which were visible and facilitated fastening points make it tiresome to the operation

unfasten the seat

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DELTAFTX

Difficult Easy

- Heavy, clumsy and bulky seat - Easy to remove the front anchorage which had to be turned and twisted and thus loosen the seat

to remove from the car

- Obvious how to proceed - The rear anchorages were stiff and

hard to loosen and the seat had to be worked out of position

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Conventional

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Why did you find the seat stable or unstable?

Unstable Stable

- It was possible to move the seat

- Only straps held the seat in position and they were hard to tighten. An inertia-reel seat belt cannot be tightened

ISOFTX

Unstable Stable

- The seat was only fastened with two anchorages; there should have been an anchorage in front as well

- The child seat could be moved on the car seat

- The seat could not be moved

- The anchorages gave a durable impression as they were made of steel and fastened to the car

DELTAFIX

Unstable Stable

- Thanks to the lower anchorage the seat seemed satisfactorily secured

- The seat was properly secured as it could not be moved

- The seat is fastened by three anchorages on the outer edges of the seat, which are then fastened in the chassis

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Conventional

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Why did you find the seat safely or unsafely secured?

Unsafely Safely

- You do not know whether the seat is mounted correctly or incorrectly

- The seat is not secured but moves to and fro

- One is accustomed to using seat belts and buckles. Besides, it is a fact that seat belts can stand a collision

ISOFITX

Unsafely Safely

- The seat should have still another anchorage point as two do not seem enough in a collision

- The seat could be rocked and moved laterally

- No seat belt holding the seat

- The seat seemed properly secured in a stable way

- The seat was correctly mounted as a "click" was heard when the buckle was fastened

- Strong, firmly attached steel anchorages which are part of the car

DELTAFIX

Unsafely Safely

- Won't the two rear anchorages break in a collision? They seem thin and may twist out of position

- The seat seemed to be secured in a stable way and could not be moved as it was fastened in three positions

- The lower anchorage which secured the seat properly made the seat feel safely secured

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3.5 Subjects' rankings of the three systems

Having tested all the systems, the subjects had to rank the three systems according to how easily they could be put into position, how obvious they were to mount and demount, how easily they could be removed, how stable they seemed when fastened and how safe they seemed. The respondents were asked to use the figure 1 for the system ranked highest in each question of ranking and the figure 3 for the system which was ranked lowest. The system ranked as number 2 was naturally given the figure 2. If subjects could not separate the ranking of the two systems, these could be given the same ranking order. If someone did not notice any difference between the various systems, the subject was asked to put a cross in the square "No difference was noticed between seats".

At the end of the ranking form, two questions were posed, asking whether either of the two new systems was so much better than the old system that they could consider changing and how much they were then willing to pay for having one of the new systems mounted in their car. The ranking form is shown in Appendix 6.

The ranking order, the number of subjects who could consider changing systems and the amount of money they were willing to pay for the new system are reported below.

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Ranking of seats

How easy was it to mount the seats?

Mean value

1) ISOFIX

»

(1.1)

2) DELTAFIX

(1.9)

3) CONVENTIONAL SEAT

(2.9)

How obvious was the fastening of the seats?

1) ISOFIX

(1.1)

2) DELTAFIX

(1.8)

3) CONVENTIONAL SEAT

(2.8)

How obvious was the unfastening of the seats?

1) ISOFIX

(1.2)

2) DELTAFIX

(1.8)

3) CONVENTIONAL SEAT

(2.4)

How easily could the seats be removed?

1) ISOFIX

(1.2)

2) DELTAFIX

(1.8)

3) CONVENTIONAL SEAT

(2.6)

How stable did the seats seem when secured?

1) DELTAFIX

(1.0)

2) ISOFIX

(2.1)

3) CONVENTIONAL SEAT

(2.8)

Which system seemed safest?

1) DELTAFIX

(1.2)

2) ISOFIX

(2.0)

3) CONVENTIONAL SEAT

(2.6)

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The number of subjects who found one of the new systems so much better than the system they were used to that they could consider changing systems at a certain cost is reported in Figure 16.

I EH Percent of subjecg

100

80

60

40

20 \

R

OR

R

\ \ N OR \ \ N O O R \ \ N OR \ \ RN OR 0 . u . i . . a & ® a. os

Willing to change Not willing to change

Figure 16 The number of subjects who could consider changing systems at a

certain cost

In the case of those who were willing to change systems at a certain cost, how

much _{were they willing to pay to have the new system}

installed in their car? The

amount subjects were willing to pay is shown in Figure 17.

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24 r- Percent of subjects | 50 40 30 ooooooooooooooooooooo 20 ooooooooooooooooooooo 10 \ \ \ \ \ \ \ \ \ \ \ \ \ W 100 200 300 400 500 600

700-SEK 600 SEK = 100 US$

Figure 17 How much were subjects willing to pay to have the new system

mounted in their car?

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235

4 DISCUSSION

4.1 Discussion of Methods

An important matter concerning groups in different studies is their representativeness (Kerlinger 1973), i.e. whether the results can be generalized to the population from which the sample is drawn. The group examined in this study is not a random sample of all parents of small children in the whole of Sweden. The aim was never to perform a large-scale experimental study fulfilling all demands on representativeness. It is an attempt to reflect parents' views, ideas and assessments concerning three different systems for fastening a rearward facing child seat in the front seat of a passenger car. If the aim of the study had been to be generalized statistically, it would have had to be made more superficial, i.e. the number of interview questions would have had to be minimized or cut out completely and the number of subjects would have had to be increased considerably. Subjects should also have been randomly chosen to participate in the test. Furthermore, they had not been able to test and compare the three systems as only one seat of each of the two new types is available. If the cars with the two new systems had been transported throughout Sweden in order to perform testing with nationwide coverage or if the subjects living a long way from the VTI had been asked to test the three systems in Linkoping, the arrangement of the experiment would have grown out of all proportion.

Before mounting a seat, subjects were requested to read the instruction on how the seat was to be fastened in the front seat of the car. The idea was that as each seat that is sold must have an instruction, subjects should be furnished with an instruction for each seat they tested. It would have been interesting to see how subjects had managed to handle the three systems without having access to an instruction. If a similar study is to be carried out, it should be considered whether subjects should not start mounting the seats without the aid of an instruction. The systems would show even further how self-instructive they are.

The aim was an "in-depth" study and a qualitative evaluation (Patton 1988) of subjects' assessments of the three different systems. The method used has been illustrative (Patel 1987). An illustrative method is based on describing the actual structure and the contents of people's statements or recordings of observations. This study describes subjects' views of the new systems through interviews and how subjects managed to use the systems through observations by research

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26

leaders and video recording. The manufacturers of the new FIX systems should be able to use this result in further development work.

It should be possible to transfer the subjects' views and ideas to parents of small children in the rest of Sweden and the raw data obtained should give a hint of the result of a large experimental study, even though they cannot be generalized statistically for all parents of small children in Sweden. Despite the fact that the number of subjects is very small, it was however used as a percentage instead of specifying the number of persons fulfilling different tasks, in order to simplify the result for the reader.

4.2 Discussion of Results

According to the research leaders' notes, it is difficult to fasten an ordinary child seat in the front seat of a passenger car. The research leaders recorded whether subjects managed to fasten the seat at once, possibly reflecting a little, whether they asked for help or whether they mounted the seat incorrectly. A total of 63% of the test group mounted the ordinary seat incorrectly or asked for help or did not manage to mount the seat. The situation is the opposite for the two new systems. Eighty-seven per cent of the test group managed to mount the DELTAFIX and ISOFIX seats directly or after some reflection.

Demounting the different seats fastened with the three systems did not seem to be a problem as 97.8% of the subjects understood directly how to unfasten the seats.

The interesting fact about the above result is the high percentage of error of the ordinary system, which all subjects had used earlier, and the low percentage of error of the two new systems, which no subject had seen or used. All subjects would probably cope with the new systems directly if they were allowed to try again. This result clearly shows how easy and self-instructional the two new systems are from the user's point of view. As there is a certain percentage of error of the new systems, the result also points to the importance of further development of the new FIX systems, making them easier to use and of a standard that all car manufacturers will be prepared to use.

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27

The fact that the ordinary fastening device with fastening strap and seat belt showed such a disastrous percentage of error may be caused by the fact that 100% of the subjects experienced that the instruction was of no help when mounting the child seat. The instruction used by subjects is, however, not inferior to the instructions for most child seats on the market. This result shows the importance of taking a great deal of trouble to produce an instruction that is easy to understand and shows how to fasten the seat in the car in order to minimize incorrect mounting of child seats.

The result of the ranking order of the different seats is interesting. The ISOFIX system or the DELTAFIX system is always ranked as number 1 or 2. The conventional "old" system is always ranked as number 3 in all questions. The ISOFIX system was ranked highest by subjects in terms of simplicity of use, 1.e. how easily the seats could be put in place, how obvious the fastening and unfastening of the seats were and how easy they were to remove. The DELTAFIX system, on the other hand, was ranked higher than the ISOFIX system in terms of stability and safety. This result probably depends on the third anchorage of the DELTAFIX system, making the seat easy to fasten in a more stable way than the two anchorages of the ISOFIX system. A conclusion to be drawn is that subjects' opinions of the simplicity of the ISOFIX system and of the stability and safety of the DELTAFIX system should be used in order to obtain an optimum system that appeals to consumers. In the future, consumers will pay to have these systems mounted in their cars.

It is fortunate that so many (89%) found one of these two new systems so much better that, at a certain cost, they are willing to change systems. Parents were also willing to pay a considerable amount of money to have the new systems mounted in their cars. The majority of parents (68.4%) were willing to pay 500-700 SKR for the new systems.

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28

5 PROPOSAL FOR FUTURE RESEARCH

As, in the long run, these new types of systems are considered to be a European Standard, a more comprehensive study should be carried out in several European countries for the comparison of results. When carrying out identical studies in various countries, it will be possible to check whether parents of small children in other countries give priority to the same matters as Swedish parents of small children. Knowing what parents in other countries give priority to should facilitate Swedish development and marketing of the FIX systems.

This Swedish model of study should be a basis for a study covering all Europe as the model proved to be simple and efficient. The only modification needed is to translate the Swedish questionnaire into other languages.

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29

6 _ REFERENCES

Kerlinger, Fred N. Foundations of behavioural research, Third edition, Holt, Rinehart and Winston, Forth Worth, TX, 1986.

Patel, Runa. Elementary research methods (in Swedish), Studentlitteratur, Lund, 1987.

Patton, Michael Quinn. Qualitative evaluation methods, Tenth printing, SAGE Publications Ltd, London, 1989.

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Appendix 1 Page 1

Mounting Instruction: ISOIFIX

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Appendix 1 Page 2

Mounting Instruction: DELTAFIX

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Appendix 1 Page 3

Mounting Instruction: CONVENTIONAL SEAT

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Appendix 2

Questions posed before subjects had mounted any of the child seats

Sex

D Male

E] Female

Age ...l...l...

[] Do you have a driving licence?

[] Yes

[] No

How many children do you have? ...

Age Of CR1IGTEM

000 see see see eee ee eee ee ee ee ee ee ee eee ee s ees

How many child seats have you used? ...

How often do/did you fasten or unfasten the child seat?

H Very often

D Often

H Seldom

Never

What type of seat did you use recently?

000000000000000000000000000000000000000000000000000000

Thank you! We'll fill in the rest.

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Appendix 3

The protocol of the research leader

Mounting Demounting

Ordinary [] Directly [] Directly

[_] After some time [_] After some time

_] Help _] Help

[] Cannot manage [_] Cannot manage [_] Incorrect mounting

ISOFIX [] Directly [] Directly

[_] Help _] Help

[] Cannot manage [] Cannot manage [] Incorrect mounting

DELTAFIK [ Directly [] Directly

_] Help _] Help

[_] Cannot manage [J] Cannot manage [_] Incorrect mounting

Comments ORDINARY esses seve eee ee ee ee ee ee eee ee eee ee ee ee ee e ees

Comments ISOFIX! 0666666666 66666 ee ee eee eee ee een ee ee ee n eee e eee

Comments DELTAFIX! 606666 e ev ee eee eee ee ee ee e eee n ee e ee en ee ee ek

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Appendix 4 Page 1

Reply card, ISOFIX

Did you find the instructions on the seat easy or difficult to understand?

_] Very easy to understand _] Easy to understand

[_] Neither easy nor difficult to understand [-] Difficult to understand

H Very difficult to understand

Was the instruction of great or little use when fastening or unfastening the seat?

Fastening: Unfastening:

[_] Considerable help [_] Considerable help

LJ] Great help [L] Great help

[_] Little help [_] Little help

[_ No help [_] No help

Did you find that the seat you just tested was easy or difficult to get into position?

[_] Very easy to get into position _] Quite easy to get into position

[_] Neither easy nor difficult to get into position I Quite difficult to get into position

[_] Very difficult to get into position

How obvious was the attachment of the seat?

D Obvious

Quite obvious

Far from obvious

Please stop. We're going to ask you a question.

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Appendix 4 Page 2

How obvious did you find the demounting of the seat?

D Obvious

Quite obvious

Far from obvious

Was it easy or difficult to remove the seat?

_] Very easy to remove

_] Quite easy to remove

[_] Neither easy nor difficult to remove

I Quite difficult to remove

[_] Very difficult to remove

Please stop. We're going to ask you a question.

Did you find the seat stable?

_] Very stable

[_] Quite stable

I Neither stable nor unstable

H Quite unstable

[_] Very unstable

Please stop. We're going to ask you a question.

Did you find that the seat was fastened in a safe way?

_] Very safe

[_] Quite safe

[_] Neither safe nor unsafe

[_] Quite unsafe

[_] Very unsafe

We're going to ask you a question.

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Appendix 4 Page 3

Reply card, DELTAFITX

_] Very easy to understand __] Easy to understand

[_] Neither easy nor difficult to understand -] Difficult to understand

[_] Very difficult to understand

[] Great help [] Great help

[] Little help [_] Little help

[_] No help [_] No help

__] Very easy to get into position [_] Quite easy to get into position

[_] Neither easy nor difficult to get into position _] Quite difficult to get into position

[_] Obvious Quite obvious Far from obvious

Please stop. We're going to ask you a question.

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Appendix 4 Page 4

D Obvious

[_] Quite obvious

Far from obvious

Was it easy or difficult to remove the seat?

_] Very easy to remove

_] Quite easy to remove

[_] Neither easy nor difficult to remove

[_] Quite difficult to remove

[_] Very difficult to remove

Please stop. We're going to ask you a question.

Did you find the seat stable?

_] Very stable

[_] Quite stable

[_] Neither stable nor unstable

[_] Quite unstable

_] Very unstable

Please stop. We're going to ask you a question.

Did you find that the seat was fastened in a safe way?

_] Very safe

[_] Quite safe

[_] Neither safe nor unsafe

[_] Quite unsafe

I Very unsafe

We're going to ask you a question.

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Appendix 4 Page 5

Reply card, CONVENTIONAL SEAT

_] Very easy to understand _] Easy to understand

[_] Neither easy nor difficult to understand [_] Difficult to understand

[_] very difficult to understand

[] Great help [] Great help

LJ] Little help ] Little help

[] No help [] No help

_] Very easy to get into position H Quite easy to get into position

[_] Neither easy nor difficult to get into position _] Quite difficult to get into position

[_] Obvious Quite obvious Far from obvious

Please stop. We're going to ask you a question.

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Appendix 4 Page 6

D Obvious

Quite obvious

Far from obvious

Was it easy or difficult to remove the seat?

_] Very easy to remove

_] Quite easy to remove

[_] Neither easy nor difficult to remove

[_] Quite difficult to remove

_] Very difficult to remove

Please stop. We're going to ask you a question.

Did you find the seat stable?

[_] Very stable

[_] Quite stable

I Neither stable nor unstable

[_] Quite unstable

_] Very unstable

Please stop. We're going to ask you a question.

Did you find that the seat was fastened in a safe way?

_] Very safe

[_] Quite safe

[_] Neither safe nor unsafe

[_] Quite unsafe

_|] Very unsafe

We're going to ask you a question.

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Appendix 5 Page 1

Questions after testing one of the systems

Was thereanything that was particularly easy or difficult when fastening the seat? Please give your reasons.

... 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO seat? OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 MEDDELANDE 688A

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Appendix 5 Page 2

Why did you find the seat stable or unstable? Please give your reasons. Ordinary:

OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO

way.

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Appendix 6 Page 1 Questions after testing all the systems

Rank the three seats according to how easy they were to put into position. Assign the figure 1 to the seat that was easiest to put into position and the figure 3 to the seat that was not easy to put into position. If there was no difference between seats, enter a cross for: No difference was noticed between seats.

... Deltafix

... Isofix

...The ordinary seat

D No difference was noticed between seats

Rank the three seats according to how obvious they were to fasten. Assign the

figure 1 to the seat whose method of fastening was most obvious and the figure

3 to the seat whose method of fastening was least obvious. If there was no

difference between seats, enter a cross for: No difference was noticed between

seats.

... Deltafix

... Isofix

...The ordinary seat

D No difference was noticed between seats

Rank the three seats according to how obvious they were to unfasten. Assign the

figure 1 to the seat whose method of unfastening was most obvious and the

figure 3 to the seat whose method of unfastening was least obvious. If there was

no difference between seats, enter a cross for: No difference was noticed

between seats.

... Deltafix

... Isofix

...The ordinary seat

D No difference was noticed between seats

Rank the three seats according to how easy they were to remove. Assign the

figure 1 to the seat that was easiest to remove and the figure 3 to the seat that

was least easy to remove. If there was no difference between seats, enter a cross

for: No difference was noticed between seats.

... Deltafix

... Isofix

... The ordinary seat

D No difference was noticed between seats

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Appendix 6 Page 2

Rank the three seats according to how stable they seemed when fastened. Assign the figure 1 to the seat that seemed most stable and the figure 3 to the seat that seemed least stable. If there was no difference between seats, enter a cross for: No difference was noticed between seats.

... Deltafix

... Isofix

...The ordinary seat

D No difference was noticed between seats

Rank the three fastening devices according to how safe they seemed. Assign the

figure 1 to the fastening device that seemed safest and the figure 3 to the

fastening device that seemed least safe. If there was no difference between seats,

enter a cross for: No difference was noticed between seats.

... Deltafix

... Isofix

... The ordinary seat

D No difference was noticed between seats

Did any of the new systems seem so much better than the system you are used

to that you would consider changing systems at a certain cost?

Yes

D No

If yes, how much are you willing to pay for having the new system mounted in

your car? (State the highest amount possible).

100 SKR

200 SKR

300 SKR

400 SKR

500 SKR

600 SKR

700 SKR or more

L

O

L

O

MEDDELANDE 688A

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Appendix 7

Fix test order scheme

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Appendix 8

Instruction to subjects

You will be participating in a test, the idea of which is to fasten and unfasten three child seats. The only difference between seats is that they have different devices for fastening the child seat in the front seat. Each seat is supplied with an instruction describing how to fasten the seat in the front seat of the car.

All seats are to be placed in the front seat of the car, i.e. the child will travel in a rearward facing position.

If you don't understand how to fasten or unfasten the seat after reading the instructions, you may ask the research leader.

Before the test starts, you will have to fill in a number of background questions and after fastening and unfastening a child seat we'll ask you for your opinion about the system in question. Having tested all three seats, we'll ask some further questions where you'll have to compare the three systems.

Take your time and consider the way the seats are fastened. Don't be afraid to treat the systems roughly.

The test is estimated to take one hour.

Good luck!

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Appendix 9 Page 1

Status report about ISOFIX to GRSP

ISOFIX

Status report May 1991 Thomas Turbell

Swedish Road and Traffic Research Institute

'

Anders Abrahamsson

SAAB Automobile AB

Bjorn Lundell

VOLVO Car Corp

Claes Tingvall

FOLKSAM

Abstract

This document describes the status of a new concept

for the interface between child restraint systems and

cars. This concept, ISOFIX, is under development

within the ISO working group ISO/TC22/SC12/WGI1

"Child Restraint Systems in Road Vehicles".

GRSP

Geneva 1991-05-22

Swedish Road and Traffic Research Institute, VTI

S-581 01 LinkOping

Phone +46 13 204369

Fax +46 13 141436

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Appendix 9 Page 2

ISOFIX

1. Introduction

Since the ECE Regulation 44 "Child Restraint Systems" (CRS) became effective in 1981 there has been a positive development of the CRSs. More than 350 systems have been approved in Europe.

The main problem today seems to be that the CRSs are not used at all or that they are used incorrectly. Misuse rates of up to 50% have been reported. This depends mainly on the fact that most devices have to be installed with the adult seat belts in the cars. These belt installations are not, and have never been, intended for this

appli-MEDDELANDE 688A

cation. The following problems have been ob-served with the present "universal" systems: - The CRS is unstable, especially when retractor

belts are used.

- The belts are not long enough.

- The lower anchorages are placed too far forward. - The belt routing in the CRS is difficult to

understand.

Fully integrated systems, where the CRS is an in-tegral part of the car, have been proposed. This is of course a good solution but perhaps too expen-sive to be installed on all seating positions in all cars.

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Appendix 9

2. General objectives

The problems mentioned above were discussed within the ISOgroup and it was concluded that there is a need for a standardized interface for CRSs. A comparison can be made with the audio equipment in the cars where all radios etc will fit into a standardized hole in the instrument panel. After discussions within the ISOgroup the following preliminary specifications were set up:

1. Standardized fixation points possible to integrate into the car design for all seating positions. 2. The fixation points must be equally useful for all

types of CRSs.

3. The fixation points must not interfere with other systems in the vehicle, or rely on other restraint systems.

4. The fixation points should minimize the risk of misuse.

5. The installation in the car should be simple and cheap.

Fig. 1 Seat fixture

At the November 1990 meeting of the ISO-group the ISOFIX concept was presented by the Swedish delegation. It is based on two rigid elements that are installed between the seat cushion and seat-back and can be turned in position by hand. Fig. 1 shows the position of the ISOFIX element in the car.

It is essential to this concept that all solutions are non-propriatory and that no patents etc will inter-fere with the concept. This has been accepted in the ISOgroup as a necessary condition for this development.

MEDDELANDE 688A

Page 3

All current types of CRS should be possible to install with this device after adding the necessary fixations. Fig. 2-8 illustrates some possible combi-nations.

Fig. 2 Carbed

Fig. 3 Babyseat

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Appendix 9 Page 4

The devices shown in Fig. 2-4 can be expected to have a serious problems with passenger airbags when installed in the front seat. With a suitable connection in the ISOFIX mounting this problem can be eliminated by automatic disconnection of the airbags when a CRS is installed.

Fig. 8 Booster cushion

Fig. 9-10.

Fig. 9 Pet box Fig. 6 Booster with shield

Fig. 7 Booster seat Fig. 10 Luggage container

MEDDELANDE 688A

When the ISOFIX mounting is available it is also possible to use it for other products as illustrated in

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Appendix 9

3. The first prototype

In April 1991 the first prototype was developed within the Swedish delegation to the ISO working group. Two passenger cars were equipped with ISOFIX fittings (Fig. 11-12) and two rearward facing child seats and one booster cushion were modified with ISOFIX fittings (Fig. 14-16). A theo-retical strength analysis was made using the finite element method. This analysis showed that the di-mensions of the prototypes were enough to with-stand a frontal collision at 70 kmph and a rear end collision at 40 kmph, simulating being impacted at 70 kmph, without any support other than the ISOFIX fitting. The prototypes were shown to the ISOgroup in Paris on April 25, 1991.

Fig. 12 Installation in car seat 4. The next step

4.1 ISO

All members of the ISOgroup have been invited to study this proposal and to submit comments. Some manufacturers have already started to build prototypes.

MEDDELANDE 688A

Page 5

Fig. 14 Child seat with ISOFIX fittings

Fig. 15 Front seat installation

There is of course a lot of work to be done before a final solution has been reached. Details of the present proposal eg the couplings will probably be changed and as well as the dimensions.

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Fig. 16 Rear seat Installation " 4 0 ns T..__ _ (" f M 327

Fig. 17 Preliminary dimensions

MEDDELANDE 688A

Appendix 9 Page 6

4.2 GRSP

The future of the ISOFIX concept is very much dependent upon how the international and national regulations and rules are adopted to deal with this approach. In Regulation 44 it seems to be neces-sary to introduce a new "ISOFIX" category of CRS. These systems should be tested on a sled with the ISOFIX fittings. There is also a need for an ap-proval of cars with the ISOFIX elements installed. Even if the final ISOFIX solution from ISO will not be ready for some time it is considered essential that work 'on a suitable update of Regulation 44 is initiated.

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