Causse, Effects of Roof Height on car ingress/egress movement
Effects of Roof Height on car Ingress/Egress Movement
J. CAUSSE*†, X. WANG* and L. DENNINGER†
* Université de Lyon, F-69622, Lyon, France, Ifsttar, LBMC, UMR_T9406, F-69675, Bron, France
Université Lyon 1, F-69622, Villeurbanne, France
† PSA Peugeot-Citroen, Vélizy-Villacoublay, France
Abstract
In recent years, many researches have been launched to investigate car ingress/egress motion and to understand
perceived discomfort. But few of them were focused on the influence of specific car design parameters. The aim
of this study was to experimentally investigate the influence of the roof height on car ingress/egress motion.
26 young and healthy volunteers of different statures participated in the experiment. An adjustable car mock-up
was used, allowing simulating different car configurations. Volunteers were asked to identify two roof heights:
1/ the first roof height Ht1, for which they began to feel discomfort due to roof and 2/ the lowest acceptable roof
height Ht2, below which they would not accept for getting in and out. Three different car configurations were
tested: a small car, a medium-size car and a minivan. Ingress/egress motions were captured using the
optoelectronic Vicon® system, reconstructed and analysed.
The results showed that both Ht1 and Ht2 were neither influenced by the car configuration nor by the stature.
Only a difference of 45 mm between Ht1 and Ht2 was observed in average. The motion analysis showed that tall
volunteers flexed more the trunk than short ones thanks to a larger space available between the steering wheel
and the seat. The comparison of the postures when the head passed under the roof showed that only head flexion
differed between the roof heights Ht1 and Ht2. The results will be helpful for optimising car design parameters
by improving the comfort of the car ingress and egress.
Keywords: Motion analysis, Discomfort, Car ingress/egress movement.
1. Introduction
The ease of getting in and out of a car is one of the
ergonomic issues that catch the attention of many
car manufacturers (Wegner et al. 2007). It
represents the first physical contact of the customer
with the car. Therefore, it is important to ensure a
pleasant sensation while accessing the car.
The car ingress/egress is a complex motion because
of the strong interactions between the driver and the
environment. Indeed, a driver has to avoid
simultaneously several car elements while
controlling his/her balance.
Most of drivers get into a car with the right leg first
strategy (Chateauroux 2009). The corresponding
ingress motion can be divided into 4 phases. Firstly,
the driver gets the right foot inside the car while
standing on the left foot only. Secondly, once the
right foot on the car floor, he/she transfers the body
weight towards the seat while standing on both feet.
Thirdly, once seated, the left foot gets into the car.
Finally, he/she moves the body in the middle of the
seat to adopt a driving posture.
*Corresponding author. Email: xuguang.wang@ifsttar.fr
For the egress, the left leg first strategy is the most
commonly used. The motion can be divided in the 3
phases. Firstly, the driver moves the left foot out of
the car while being seated. Secondly, once the left
foot on the ground, he/she stands up with both feet
being supported. In addition, the hands can help the
weight transfer by pulling/pushing on the steering
wheel. Finally, the right foot gets out while
standing on the left foot.
In recent years, several research groups have
launched research programs trying to identify the
motion strategies used by the driver (Ait El
Menceur 2008, Chateauroux 2009), to simulate the
motion using a Digital Human Model (DHM)
(Cherednichenko 2006; Lempereur 2006; Rigel
2006) and to understand the associated discomfort
(British Department of Transport 1985; Giacomin
et al. 1997; Petzall 1995, Causse et al. 2009).
At Ifsttar (French Institute of Science and
Transport, Development and Networks), a databased motion simulation approach was proposed
and applied to the car accessibility (Monnier et al.
2006 and Chateauroux et al. 2007). In addition, the
1
Causse, Effects of Roof Height on car ingress/egress movement
neutral motion concept was proposed to assess the
discomfort of a task oriented motion like car
ingress/egress (Dufour and Wang 2005). The basic
idea of the “neutral motion concept” is to
experimentally identify less constrained movements
and to compare them with more constrained ones
by controlling design parameters.
However, few of these studies focused on the
influence of specific car design parameters on car
ingress/egress motion and discomfort. Among the
parameters influencing ingress/egress, the roof
height, the sill height and width are probably the
most critical ones (Giacomin and Quattrocolo 1997,
Causse et al. 2009). Therefore, an experiment was
set up to experimentally investigate the influence of
these parameters. Due to limited length of this
paper, only the results related to the roof height are
presented.
More specifically, the present study aimed at
answering the following questions: What is the gap
between an acceptable and a non-acceptable roof
height? How this gap is affected by the driver’s
anthropometry and car type? How does a
biomechanical motion analysis help to understand
the influence of the roof height?
2. Materials and Methods
2.1. Experimental design
This experiment was mainly designed in order to
understand the discomfort due to the roof. Thus two
specific roof heights were measured according to
the volunteer indications:
 The first roof height (Ht1) that began to
create discomfort, above this height, the
roof is not responsible for any discomfort.
 The lowest acceptable roof height (Ht2)
below which the driver would not accept
to get in and out.
The sill width was also studied during this
experiment and three specific widths were tested.
Three different car configurations according to the
seat height to the ground (Hs) were tested: a small
car (Hs1), a medium-size car (Hs2) and a minivan
(Hs3). All other car dimensions were defined
according to the seat height to simulate currently
existing cars. Figure 1 illustrates the definition of
the main car dimensions used in this study and
Table 1 summarized them.
In addition to these three car configurations, two
existing car configurations (Cf1 and Cf2) were also
defined for training the volunteers to the use of the
discomfort questionnaire: one being well rated for
car ingress/egress (Cf1) and the other considered as
being very uncomfortable from the customers’
survey of PSA Peugeot-Citroen (Cf2).
In total, 25 configurations were tested for each
volunteer. For all seat heights, the trial was ordered
as following: they were asked to identify Ht1 and
then Ht2 iteratively. They tested the intermediate
roof height HtM (mid height between Ht1 and Ht2)
and finally the sill widths. The order of presentation
of the three seat heights was randomized for each
volunteer. The trials on Cf1 were repeated 3 times
during the experiment (one at the beginning, one in
the middle and one at the end of the experiment).
Figure 1: Definition of car dimensions given in Table 1.
Table 1: Main configurations dimensions tested (in mm).
Seat height
above ground
Sill height
above ground
Sill height
above floor
Doorway
Width
Sill width
from S-wheel
Roof width
from S-wheel
Id
Hs1
Hs2
Hs3
Cf1
Cf2
1
470
550
700
695
448
2
360
360
420
382
375
3
130
100
70
30
154
4
900
850
850
817
998
5
470
460
450
431
549
6
220
220
250
200
240
2.2. Volunteers
26 young and healthy volunteers participated in the
experiment. Only people with a driving licence and
currently driving were retained. They were selected
according to their stature in order to cover a large
range of the French driver (from 5 th percentile
female to 95th percentile male). They were divided
in three groups: short women (S), averaged men
and women together (A) and tall men (T). The main
characteristics of these groups are summarized in
Table 2.
Table 2: Main characteristics of the volunteers groups
(mean ± standard deviation).
Groups
Nb
Stature
(mm)
Short
9W 1594±28
Women
Mixed 2W
1722±40
Average 6M
Tall
9M 1835±23
Men
W: Women, M: Men.
Weight Age
(kg)
(yrs)
Sitting
height (mm)
55±09 30±6
841±24
71±12 30±5
884±14
79±08 30±5
963±26
2
Causse, Effects of Roof Height on car ingress/egress movement
2.3. Experimental set-up
An adjustable car mock-up was used to simulate
different car configurations. It was equipped with a
seat, a steering wheel and pedals (see Fig. 2). The
following parameters were adjustable manually: the
seat height, the car floor height, the sill height and
width, the roof height and width, and the doorway
width. The door was opened and blocked at 70° for
all tested configurations.
All car elements were specified and measured using
a standard reference point (H-point manikin J826)
and dimension definitions, described in Society of
Automotive Engineering SAEJ100 (SAE 1997).
The x axis runs positive rearward, the y axis to
driver’s right and the z vertically (see Fig. 2).
A Vicon® MX T40 motion capture system with 10
cameras, sampled at 100Hz, was used to capture the
trajectories of 44 markers (14.5 mm diameter)
placed on body anatomical landmarks. A video
camera was also used as visual support for the
motion analysis.
All external contact between the driver and the car
were recorded using four 6-axes force sensors: one
Bertec® force-plate (Model 4060-10-4000) was
positioned on the ground next to the doorframe and
a second one on the car floor. A 6-axes force-plate
was placed under the seat and a 6-axes force sensor
(Denton® 2554) was installed between the steering
wheel and the steering column. Two pressure maps
(XSensor® PX100) were laid on the seat and the
back seat. All the equipment was synchronized with
the Nexus Vicon® Software.
z
x
y
Figure 2: Adjustable car mock-up with its measurement
equipment used for the experiment.
2.4. Experimental procedure
At first, 22 main anthropometric dimensions were
measured for each participant, including the stature,
the weight and the body segments dimensions.
Then, 44 reflective markers were laid on the
volunteer for the motion capture. The participants
were photographed in a standing posture from 3
orthogonal views (front, left and right) in a
calibrated space. These postures were also captured
with the Vicon system and were used for the
kinematic reconstruction.
Afterwards, the volunteers were asked to adjust the
horizontal seat position with respect to the reference
configuration Cf1. The same seat position with
respect to the steering wheel and to the pedals was
conserved for all car configurations. As a
consequence, the driving space, especially the
distance between the seat and the steering wheel,
remained the same for all tested configurations.
Among all actual cars represented by the
configurations in this experiment, the variation in xaxis direction of the lowest point of the steering
wheel was about 25 mm. Then, the volunteers were
invited to freely get in and out, in order to get
familiar with the mock-up.
In order for the volunteers to be familiar with the
discomfort questionnaire and to learn how to
identify both roof heights Ht1 and Ht2, the
configurations Cf1 and Cf2, were tested at first.
For the identification of Ht1, an experimenter
started with a high roof and then lowered it down
progressively. For each roof height, the volunteers
were invited to test the proposed car configuration
and to tell if the roof height started to impede the
ingress/egress motion by forcing a more flexed
spine. This was an iterative process and a change of
10 mm was made when approaching to the final
adjustment. For Ht2, the similar process was
applied. The roof height was lowered until it was
considered as “unacceptable” for ingress/egress
motion. The identification of Ht1 and Ht2 was
always performed two times successively for each
tested configuration and the roof heights of the
second trial were retained for the analysis.
For each configuration, the volunteers filled out a
discomfort questionnaire. Volunteers were also
asked to locate the sources of discomfort due to the
car and the body parts which felt a discomfort. A
global discomfort of ingress and egress was rated
using the slightly modified CP-50 scale (Chevalot
and Wang 2004). Due to limited length of the
paper, the results from the statistical analysis of the
questionnaire and subjective discomfort rating are
not presented.
Finally, a complete ingress/egress motion was
recorded using the Vicon system (see Fig. 3). The
volunteers were instructed to start behind the forceplate on the ground, to get into the car without
touching the door, to adopt a driving posture with
both hands on the steering wheel for about 3
seconds, then to get out of the car, and to move one
step away from the doorframe. Participants were
free to choose motion strategy.
The experimental duration was about 4h30. A break
was proposed in the middle. The volunteers were
allowed taking a rest when required.
3
Causse, Effects of Roof Height on car ingress/egress movement
2.5. Data processing
The roof heights Ht1 and Ht2 were defined with
respect to the seat H-point (SAE 1997). In order to
analyze the variation of these two roof heights
among the volunteers, the deviations from the
average height from all volunteers were analysed:
Hti  Hti  mean (Hti) with i=1,2
In addition, the differences between both roof
heights (Ht1-2) were also computed.
The motion was reconstructed using the RPx
software (Wang et al., 2005) (see Fig. 3, for an
example). The joint angles were computed from
captured markers trajectories, by minimizing the
distance between the captured and model-based
markers positions.
The average residual distance between captured
marker positions and corresponding model-based
ones was of 10±5 mm in average for all markers.
 The shoulder (ϴ_shou/seat) rotation with
respect to the seat, defined as the angle
between the Y axis of the global coordinate
system and the vertical plane containing the
left and the right acromion markers (Fig. 4).
 The back flexion (ϴ_back/Z), defined as the
angle between the vertical axis Z and the
vector going from the GBB (between the 8th
and the 9th thoracic) to GHB (between the 4th
and the 5th thoracic) joint centers of the
Ramsis model (see Fig. 5).
 The neck flexion (ϴ_neck/Z), defined as the
angle between the vertical axis Z and the
vector going from the marker placed on the
7th cervical vertebrae to the vertex on the
head (Fig. 5).
 The left hip (ϴ_hg/Z) flexion, defined as the
angle between the vertical axis Z of the
global coordinate system and the vector
going from the left hip to the left knee
centers.
x
y
Figure 4: Definition of the pelvis (left) and shoulder
(right) rotation with respect to the seat.
Figure 3: Example of a typical car ingress motion and
results of the kinematic reconstruction. The purple and
yellow arrows represent the contact force and moments.
In order to investigate the influence of roof heights
on the motion, the key frame corresponding to the
instant when the head passed under the doorframe
was detected when getting in the mock-up. The
posture at this key frame was analyzed using the
following variables:
 The pelvis position (X_pelv, Y_pelv and
Z_pelv), defined in the global coordinate
system (centred on the seat H-point and
presented in Fig. 2) as the middle point
between the hip joint centers.
 The pelvis (ϴ_pelv/seat) rotation with
respect to the seat, defined as the angle
between the Y axis of the global coordinate
system and the vertical plane containing the
left and the right hip centers (see Fig. 4).
Figure 5: Definition of the back and the neck flexion.
In Addition, in order to characterize the interaction
between the volunteer and the car at this key frame,
the following distances of the body to the car
elements were also defined:
 The distance between the chest and the
steering wheel (D_ches/wh) defined between
the marker on the suprasternal notch of the
sternum and the center of the steering wheel.
 The smallest distance between the head and
the roof (D_head/ro).
 The smallest distance between the head and
the front doorway (D_head/fd).
4
Causse, Effects of Roof Height on car ingress/egress movement
3. Results
3.1. Roof heights Ht1 and Ht2
The repeatability of the identification of Ht1 and
Ht2 was checked by comparing 1/ the values
identified twice successively for Ht1 and Ht2 for
the configuration Hs1, Hs2 and Hs3 and 2/ those
identified during the 2nd and the 3rd repetition on the
configuration Cf1 (see Table 3). The results showed
a good repeatability of the roof height identification
for both of them.
Table 3: Mean values and SDs of the repeatability of Ht1
and Ht2, according to the values identified twice
successively (Hs1, Hs2 and Hs3) and those identified
during the 2nd and the 3rd repetition on Cf1 (in mm).
Ht1
Ht2
Hs1
7±5
7±5
Hs2
6±7
6±6
Hs3
8±8
7±5
Only a difference of 45 mm between Ht1 and Ht2
was observed in average. The differences between
the three stature groups and those between three
seat heights were also very small (< 10 mm).
A two-way Anova were performed on Ht1, Ht2 and
Ht1-2. No significant effects of the volunteer group,
car configuration and their interaction were found.
3.2. Posture analysis when the head passed under
the roof
Table 5 gives the means and standard deviations of
the 11 parameters charactering the posture when the
head is under the roof. Figure 6 compares the
movements near to the key frame when the head
passing under the roof for car ingress and egress.
Cf1
11±09
13±12
Table 4 presents the mean values and the standard
deviations of the gap between the roof heights and
their mean value (ΔHti) as well as those of the
difference between both roof heights (Ht1-2).
Table 4: Mean values and SDs of the variations of the
roof heights Ht1 and Ht2 to their respective mean and
their difference Ht1-2, according to the volunteer groups
(S: short, A: average-height, T: tall) and the
configurations (Hs1, Hs2 and Hs3) (in mm).
S
A
T
Hs1
Hs2
Hs3
All
ΔHt1
-3±25
-7±33
9±29
-1±29
-2±29
3±31
0±30
ΔHt2
0±25
-9±35
8±26
4±28
-2±26
-3±34
0±29
Ht1-2
42±23
47±18
46±30
39±21
45±26
50±25
45±24
The results showed that Ht1 and Ht2 remains closed
to their mean values for all groups of stature and all
seat heights, suggesting that a short woman and a
tall man had almost the same requirement for the
roof height.
Figure 6: Posture of a short woman (left) and a tall man
(right) few seconds before and after that the head passes
under the roof during the ingress (1st line) and the egress
(2nd line) motion.
In case of the ingress, the volunteers had to handle
with several constraints: keeping the balance while
trying to avoid the collision between the head with
the roof, the right leg with the steering wheel.
Table 5: Means and SD of variables for the analysis of the posture and the proximity with the car elements when the head
passes under the roof during the ingress motion.
S
A
T
Hs1
Hs2
Hs3
Ht1
Ht2
All
X_pelv (mm)
-88±28 -18±36
29±40 -24±55 -18±59 -28±66 -23±60 -24±60 -23±60 G***
Y_pelv (mm)
-66±35 -42±40 -19±24 -22±27 -25±26 -76±43 -44±43 -41±41 -41±41 S***,G***
Z_pelv (mm)
2±15
0±16 -12±17
-5±18
-5±16
-1±18
-2±18
-5±15
-4±17 G***
ϴ_pelv/seat (°)
23±10
27±12
26±11
31±11
26±09
18±08
25±11
25±11 25±11 S***,G*
ϴ_shou/seat (°)
17±7
19±8
21±4
21±7
19±6
16±6
18±7
19±7
19±7 S***,G***
ϴ_back/Z (°)
22±10
32±07
34±07
32±09
29±10
28±09
30±10
29±09 30±09 S**,G***
ϴ_neck/Z (°)
45±10
59±10
64±09
54±12
57±11
58±13
52±11
62±11
56±12 S*,R***,G***
ϴ_hg/Z (°)
89±19
92±11
90±10
83±10
88±11 101±13
92±13
90±15 90±13 S***
D_ches/wh (mm) 291±33 326±39 368±32 337±51 331±51 323±40 327±48 333±47 330±47 S***
D_head/ro (mm)
50±25
59±29
64±22
64±28
62±25
49±21
64±28
50±24
58±26 S***,R***,G**
D_head/fd (mm) 142±30 140±35 157±27 141±36 151±30 148±28 153±33 138±30 147±31 R**,G**
* p<0.05, **p<0.01, ***p<0.001: significance in analysis of variance. S: Seat height, R: Roof height, G: volunteers groups.
5
Causse, Effects of Roof Height on car ingress/egress movement
For the egress, the head passed under the roof when
the volunteers were still seated after getting their
left foot out of the car. When the volunteers began
to leave the seat, their head was already outside of
the car for all volunteers on all configurations. The
volunteers were thus in a stable seated position to
pass their head under the roof (see Fig. 6). In
addition, while the left foot got outside of the car,
the volunteers directed their body to be in front of
the doorframe. The rotation of the shoulder with
respect to the seat was of 35±10° in average. The
volunteers were thus not impeded by a collision
with the steering wheel and the front doorframe.
The ingress motion appeared thus more critical than
the egress for the requirement of roof height. For
the rest of the study, it was thus decided to focus
our analysis on the ingress motion only.
First, the pelvis position was affected by the stature
and the seat height. The short women were seated
more forward and on the side of the seat than the
tall men (Fig. 7 on the left). The vertical position of
the pelvis was slightly higher for the short women
than for the tall men probably due to the seat side.
An increase of the seat height mainly led to a lateral
displacement of the pelvis position (Y_pelv) on the
side of the seat (Fig. 7 on the right).
In order to transfer their body weight inside the car,
the volunteers tended to swivel according to the
seat. An increase of the volunteer’s stature mainly
led to an increase in pelvis (ϴ_pelv/seat) and
shoulder rotation (ϴ_shou/seat) (see an example in
Fig. 8). The short women were thus more affected
by the avoidance of the front doorframe. Note also
that a clear difference existed between the low seat
height Hs1 and the high one Hs3.
During the ingress of the short women, the head
passed under the roof during the left foot get inside
the car, suggesting that they could be annoyed by
the thigh to bend their back (see on Fig. 6).
However, the left hip flexion angle (ϴ_hg/Z) was in
average very closed between the stature groups.
In order to pass their head under the roof, the
volunteers had to bend their back and their neck.
Both of back and neck flexion angles were
significantly dependent of the volunteer’s stature
and the seat height. As expected, an increase in the
stature mainly increased the back (ϴ_back/Z) and
the neck flexion (ϴ_neck/Z) (see Table 5 and Fig.
10). A significant effect of the seat height was also
found for the back and the neck flexion. However,
its effect was quite small: only a difference of 4°
was observed between Hs1 and Hs3, suggesting
that a low seat height did not favour a flexion of the
upper body.
Figure 7: Position of the pelvis on the seat when the head
passing under the roof. Figures on left are function of the
groups of stature (red for S, green for M, and blue for T);
Figures on right are functions of the seat height (red for
Hs1, green for Hs2 and blue for Hs3).
Figure 8: Comparison of the posture adopted by a short
woman (in blue) and a tall man (in red) when the head
passing under the roof.
Figure 9: Example of posture adopted by a volunteer
when the head passing under the roof. Blue and red for
respectively the roof height Ht1 and Ht2.
Figure 10: Proximity of a short woman (left) and a tall
man (right) with the car element when the head passing
under the roof.
6
Causse, Effects of Roof Height on car ingress/egress movement
Finally, it’s interesting to note that the roof height
between Ht1 and Ht2 only affected the neck flexion
(Table 5). Fig. 9 illustrates the posture of one
specific volunteer when the head passing under the
roof height Ht1 (in blue) and Ht2 (in red) on the
configuration Hs3. Both postures were very similar
under the both roof heights except for the neck
flexion. The lowest acceptable roof height Ht2
forced the subjects to flex the neck about 10
degrees more in average than the first
uncomfortable roof height Ht1.
3.3. Distance between the body and the car when
the head passing under the roof
The distance between the steering wheel and the
chest (D_che/wh) was significantly affected by the
stature group, but not by the seat height. The
average of D_che/wh was 291 mm for the short
women whereas it was 368 mm for the tall men,
confirming that the short women had much less
space to bend the back and the neck than the tall
men (see Fig. 10).
The distances between the head and the roof
D_hea/ro and between the head and the front
doorframe D_hea/fd were also smaller for the short
volunteers than for the tall ones.
4. Discussion
This study was mainly conducted to determine the
effects of the roof height on car ingress/egress
motions. Our analysis focused on the key frame
when the head passing under the roof. The principal
observations are as follows:
 Both the roof height Ht1 and Ht2 were
neither influenced by the car configuration
nor by the volunteer’s stature.
 The gap between an acceptable and a nonacceptable roof height differed of 45 mm
only, irrespective of the stature group or to
the seat height.
The most striking finding from this study was that a
short driver required almost the same roof height as
a tall person for car ingress/egress. This observation
is quite surprising at the first sight, knowing that a
difference in sitting height between the short female
group and the tall male group was 120 mm. The
detailed analysis of the posture when the head
passing under the roof showed that short volunteers
had to adopt a more upright trunk than tall ones due
to smaller space available between the seat and the
steering wheel for short persons. This is probably
the main reason that explains the requirement for
roof height was little affected by stature. In
addition, the tall men were more swivelled towards
the doorframe than the short women (see on Fig. 8),
suggesting that they were less annoyed by the
avoidance of the front doorframe.
It was also observed that the roof heights identified
by the volunteers were closed for the three seat
heights (Table 4). First, the same seat position was
conserved during the whole experiment, implying
that the space between the seat and the steering
wheel remained the same for all tested
configurations. This choice was motivated by the
fact that the distance between the steering wheel
and the upper body is mainly determined by the
upper limb length (shoulder-hand length). In
addition, although the analysis of the posture
showed that the seat height had a significant effect
on the back and the neck flexion, the difference in
both angles was less than 4° between Hs1 and Hs3,
leading to a very small change in head position.
When comparing the postures between Ht1 and
Ht2, only the neck flexion differed significantly. An
average difference of 10° was observed between
both roof conditions. This confirms that the upper
body movement is highly constraint by the space
available around the seat.
We would like to point out some limitations of the
present study. Firstly, this study was conducted
using a car mock-up without the full layout of an
actual vehicle. In addition, in order to capture
motion using surface markers, normal clothes were
not worn by the participants. Only a short was used
for men and a short and a cropped bras for women.
Secondly, the same seat position was kept with
respect to the steering wheel. This is not fully true
when looking at existing cars for which the position
and the orientation change with the seat height.
When examining the position of the lowest steering
wheel point for the existing vehicles in the range of
seat height studied in the present work, the
variation was at the most of 25 mm in x-axis, 2 mm
in z-axis direction. The orientation could differ
from 10 degrees. In the future, the effects position
and the orientation of the steering wheel should be
investigated in more details.
Thirdly, the duration of the full experiment lasted
4h30 hours in average. The identification of Ht1
and Ht2 was a long iterative process requiring
several trials of getting in and out movements. The
judgement of the effect of roof height may be
affected by fatigue. Finally, the roof height was
adjusted manually by an experimenter. Though a
small change of 10 mm was adopted for a fine
adjustment, a continuously motorised system is
definitely preferred.
5. Conclusion
In summary, our results showed that the
ingress/egress movement is strongly constraint by
the available space around the seat. As this space is
much reduced for shorter persons due to the fact
that the seat has to be positioned more forwardly,
the requirement in roof height for short women is
7
Causse, Effects of Roof Height on car ingress/egress movement
almost the same as for tall men irrespective of seat
height. The present study demonstrated that an
appropriate roof height should be determined
carefully. A small change of 45 mm in roof height
may lead to an unacceptable car configuration.
The present work also illustrates that the neutral or
less-constraint motion concept is useful for
identifying critical product design parameters and
helpful for defining motion-related discomfort
assessment when a DHM is used (Dufour and
Wang, 2005, Wang et al, 2011).
It would be interesting to extend the investigation to
other types of population, especially with disabled
and elderly people who meet more difficulties for
getting in and out of a car. The authors wish also to
pursue the study with other car elements, like the
sill width and height, to understand the influence of
these factors on ingress/egress motion and the
perceived discomfort.
Giacomin J, Quattrocolo S, 1997. An analysis of
human comfort when entering and exiting the rear
seat of an automobile. Applied Ergonomics 28,
697-406.
Lempereur M, 2006. Simulation du mouvement
d’entrée dans un véhicule automobile. Ph.D. Thesis,
Université de Valenciennes 06/04.
Monnier G, Renard F, Chameroy A, Wang X, 2006.
A motion simulation approach into a design
engineering process. SAE International Conference
of Digital Human Modelling, 2006-01-2359.
Petzall J, 1995. The design of entrances of taxis for
elderly and disabled passengers – An experimental
study. Applied Ergonomics 26(5), 343-352.
Rigel S, 2006. Entwicklung und Validierung einer
Methode zur quantitativen Untersuchung der Einund Ausstiegsbewegung in einen Pkw. Ph.D.
Thesis, Technische Universitat Munchen.
References
Society of Automotive Engineers,1997. Automotive
engineering handbook. Warrendale.
Ait El Menceur M, Pudlo P, Gorce P, 2008.
Alternative Movement Identification in the
Automobile Ingress and Egress for Young and
Elderly Population with or without Prostheses.
International Journal of Industrial Ergonomics 38,
1078-1087.
Wang X, Pannetier R, Burra N, Numa J, 2011. A
biomechanical approach for evaluating motion
related discomfort: illustration by an application to
pedal clutching movement. HCI International 2009.
Third International conference on Digital Human
Modeling. Orlando, USA, 9-14 July, 2011.
British Department of Transport, 1985. Problems
experienced by disabled and elderly people entering
and living cars. Department of Transport at the
Transport and Road Laboratory.
Wegner D, Chiang J, Kemmer B, 2007. Digital
human modelling requirements and standardization.
SAE International Conference of Digital Human
Modelling, 2007-01-2498.
Causse J, Chateauroux E, Monnier G, Wang X,
2009. Dynamic analysis of car ingress/egress
movement: an experimental protocol and
preliminary results. SAE Int. J. Passeng. Cars
Mech. Syst. 2(1), 1633-1640.
Chateauroux E, Wang X, Trasbot J, 2007. A
database of ingress/egress motions of elderly
people. SAE International Conference of Digital
Human Modelling, 2007-01-2493.
Chateauroux E, 2009. Analyse du mouvement
d’accessibilité au poste de conduite d’une
automobile en vue de la simulation - Cas particulier
des personnes âgées. Ph.D. Thesis INSA Lyon.
Cherednichenko A, Assmann E, Bubb H, 2006.
Computational approach for entry simulation. SAE
International Conference of Digital Human
Modelling, 2006-01-2358.
Chevalot N, Wang X, 2004. Experimental
investigation of the discomfort of arm reaching
movements in a seated position, SAE Transactions
Journal of Aerospace 1, 270-276.
Dufour F, Wang X, 2005. Discomfort assessment of
car ingress/egress motions using the concept of
neutral movement. SAE International Conference
of Digital Human Modelling, 2005-01-2706.
8