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SASTECH 47 Volume 8, Issue 2, September 2009
Interior Design of Long Haul Truck Cabin for
Improved Ergonomics and Comforts
Kishor Powar1
, Sukanta Majumdar2
, Prakash Unakal3
1 - M. Sc. [Engg.] Student, 2 - Assistant Professor, Product Design Centre, 3 - Professor and Head, Department of Design,
M.S. Ramaiah School of Advanced Studies, Bangalore 560 054
Abstract
The project was to design of a truck cabin for improved ergonomics and comfort for driver in Indian driving
condition. The focus was kept on the psychological and behavioral pattern of Indian drivers along with the Ergonomic
issues. Driver’s comfort is not even a factor in existing Indian trucks. Driving a truck in Indian condition such as the
condition of roads and other factors are not up to the standard. Driving throughout the day in such conditions leads to
physical and psychological deterioration of drivers. This may even lead to accidents. So it was important to design the
interior of a cabin of a truck considering ergonomics, comfort and aesthetics for existing driving conditions in India.
There is a wide scope for new modern style interior design of truck cabin for Indian market.
Gemba study and product survey were done to understand the problems of existing market. It was concluded from
these studies that the cabin of the truck is like the interior of a home. There was a need to include various types of
accessories to the dashboard for comfortable and enjoyable driving, a proper storage system of water and cooking stove
as well as a foldable bedding system for two persons. PDS was generated after understanding the needs of drivers those
were converted into technical voice through QFD. Concepts were generated according to PDS. Concepts were
represented by hand sketch and Photoshop tool. The final concept was selected based on the present trend and the
requirements of driver. The detail design of interior of the truck cabin was made by using CAD tool i.e. CATIA V5 R16.
Digital model for the final concept was rendered using Hypershot 1.5 software with all the detailing of the cabin interior
parts. Scaled mock-up model for the same was made for visual inspection.
Finally the design was analysed by RULA analysis method using “Human Activity Analysis” module of CATIA V5
R16 software was done to confirm the positions and dimensions of all the features in the truck cabin.
Key Words: Interior Design of Truck Cabin, Ergonomic Study of Driver Seat, New Modern Style
1. INTRODUCTION
Automobile styling has had an important impact
on the world-wide economy during the past century and
millions of additional vehicles have been sold because
of it. Much research has not been done in automobile
interior design in comparison to fine art or other
commercial or industrial arts. However, automobile
design affects the journey of millions of passengers to a
greater degree, ergonomically, economically and
culturally than many of the other subjects.
The task of the design team is usually split into three
major aspects: exterior design, interior design, and color
& trim design.
A long haul truck (figure 1) is designed to haul for
long distances and is equipped with an ample cab
hosting from a simple bed to almost a full house
amenities like bed, toilet, TV, audio system, air-
conditioning and kitchen etc.
Fig. 1 Long haul truck
Interior equipments in long haul truck generally include
dashboard, passive safety, shifter for selecting gear
ratios and ancillary. It also includes ancillary equipment
such as stereos, air conditioning, phones, global
positioning systems, cup holders, refrigerator, console
boxes etc.
2. PROJECT METHODOLOGY
Fig. 2 Project methodology flowchart
In this project of truck cabin interior design,
market study, literature survey and user study were
done to understand the existing problems of the users,
market segments and demand in the present market.
Silent observation method, informal interview
techniques, participatory approach, questionnaire
survey were done to collect the data about problems of
the users of trucks.
One full scale ergonomic model of the interior of
cabin was constructed to conduct the survey in
ergonomics. Also one of the existing interior of cabin of
a truck was selected for benchmarking. In this case,
TATA Novus was selected as the benchmarked product

for cabin interior design. Product Design Specification
was set after a detail study of literature and analysis of
problems.
Many concepts were created with detail design
according to the design criteria and one of them was
selected for final simulation of human activity analysis,
digital and physical mock-up model. The total process
is documented in figure 2.
3. LITERATURE REVIEW
In the new millennium, demand of trucks and
freight transport will be manifold due to economic
growth and infrastructural development in India.
Improved transport efficiency and low costs will derive
the criteria like safety, ergonomics and environmental
properties in design of cabin interior of truck.
Fig. 3 S-Curve for trucks
It is clear from the s-curve (figure 3) that only after
1980’s major focus in design of truck was shifted to
environmental issues, ergonomic issues and comfort of
driver.
4. MARKET RESEARCH
To design the interior of a truck cabin for Indian
markets it is necessary to benchmark the trucks
available in the Indian market.
Fig. 4 Tata Novus truck interior
TATA Novus truck (figure 4) comes with
unbeatable features those make the interior of the cabin
most pleasing and provide ample driver comfort. The
TATA Novus Tipper appreciates that driver comfort is
foremost, especially with the long hours of driving
involved. With these and other features for comfort,
ergonomics, safety and drive assisting, the TATA
Novus sets new benchmarks on the Indian roads.
Fig. 5 Volvo truck interior
Volvo Truck cabin interior (figure 5) was designed
to create a work environment with optimum function,
space and comfort, based on the results of several
studies among drivers and haulers. Besides space,
comfort and smart storage solutions, it gives the driver a
bright, attractive environment, which can make driver’s
work easier and more efficient.
Fig. 6 Avia Ashok Leyland truck interior
Fig. 7 Mercedes truck interior
Ashok Leyland, the flagship firm of Hinduja
Group plans to bring out Avia D series trucks (figure 6)
to India by 2010-11. Currently, the D-line series are
marketed in Czech Republic, Hungary, the UK, Ireland
and Spain from the head quarter of Avia Ashok Leyland
Motors in Prague. The acquisition of Avia by Ashok
Leyland Motors in 2006 is expected to have a good
quality product in Indian market. It is the first Indian

company to have a truck manufacturing unit in Europe.
Survey conducted by Ashok Leyland showed that
customers want both safety and comfort while covering
long distances which made them design these trucks.
The relaxed working environment and comfort
make this cabin of Mercedes truck (figure 7) ideal for
long-distance haulage. Standard-fitted comfort
suspension seat, multifunction steering wheel, air
conditioning and spring-core mattress, A level floor
throughout, ample room to move around and generous
stowage compartments and shelves, ideal also for two-
person crews.
5. USER STUDY
Silent observation method, informal interview
techniques, participatory approach, questionnaire
survey were done to collect the data about problems of
the users of trucks in Indian context. Photography was
done to grab the different activities of the driver and the
assistance within the truck cabin. The activities of
driver and cleaner were observed. Some of the common
activities were documented. After documenting
different activities of driver, inferences were made that
some extra facilities must be designed with some
refined design of existing facilities in the existing cabin
of the truck to assist the driver for comfortable driving
for long hours.
Areas such as driving area, water storage, sleeping
arrangement, cooking, storage space for cooking
utensils, switch panels, mobile charging, dial indicators,
storage space to keep belonging etc. were addressed in
this project.
The observation made was as follows: No water storage
facility is provided in any truck cabin in Indian Market.
This was a commonly observed problem in almost
every truck. Generally water is stored by the driver
using cans, barrels, utensils etc. Even Volvo truck does
not have any provision for water storage.
Enough space is provided for sleeping purposes in
the truck. Sleeping arrangements in most of the cabins
are in good condition; but in some cases, the
arrangement is made for only one person, where as
there are more than one person travel in all these trucks.
There is an essential need of safe arrangement of
cooking in the cabin, because many of the drivers use to
cook by their own and they have their own arrangement
for cooking inside the cabin, which is not safe (figure
8). They use kerosene oil stove for cooking purposes
within the cabin. Over all it costs less in comparison to
buy food from any shop. And also they do not have
proper storage area to keep those cooking utensils.
Mostly they keep those cooking utensils under the bed.
Fig. 8 Cooking activity inside the cabin
It was observed that, most of the drivers use
wooden stand below the accelerator, clutch pedals,
which give enough support to their feet while driving
and also protect their feet from heated floor. It provides
comfort while driving for a long distance.
In many cases, switches are placed in awkward
positions; sometimes they are away from reach of the
drivers when in sitting position. Drivers have to stretch
their hands when they want to operate those switches.
Most of the drivers use mobile phones. But there is
no mobile charging facility inside the cabins. The
drivers use to make their own arrangements for
charging purposes of mobile phones. No mobile phone
holder is provided on the dashboard of any truck; so the
drivers place their mobile phone at any place in the cab
or they keep it in hanging position.
There is no proper place to keep their daily
belongings inside the cabin. They are placed anywhere
within the cab. Instrument panel and other display
systems in the driver’s field of vision are sometimes
obstructed by the steering wheel. Dial indicators are not
positioned properly. Both dry and wet cloths are hanged
over a rope as there is no proper place to keep them.
6. PROBLEM DEFINITION
Driver’s comfort is not considered as a deciding
factor in design of Indian trucks. Driving condition in
India such as roads and other factors are not good.
Driving throughout the day in such conditions leads to
frustration in drivers which may lead to accidents. So it
is important to design cabin interiors considering
ergonomics, comfort and aesthetics for drivers in Indian
driving conditions.
6.1 User Feedback Analysis Process
• 91 trucks of different make and from different
parts of country were considered.
• 91 truck drivers from north, south and west zone
respectively were interviewed.
• There were total 20 questions in the form of
questionnaire given to those drivers.
• The feedback results were divided into North,
West and South zone of India.
• Feedback from each zone was separately analyzed
for conclusions.
• Feedback results were used to plot bar charts to
clarify the situations.
Fig. 9 QFD results
6.2 Quality Function Deployment
The QFD was done to convert the voice of
customer into technical voice. Results of the QFD

process done is as shown in figure 9 below. Result
shows the priority of the technical voice.
7. PRODUCT DESIGN SPECIFICATIONS
Product design specifications were decided
according to the collected data (figure 10).
Fig. 10 Product design specification
8. ERGONOMIC STUDY
Ergonomic aspects were considered to decide the
dimensions of every part of cabin design for cognitive
and physical activities for truck drivers (figure 11 &
Table 1).
8.1 Defining Work Zones
In order to do define workspace a full scale
physical model was made. The purpose of modeling
was as follow.
• To get clear idea to locate the features in the cabin.
• To define the work zones according to the usage of
features.
• To make use of anthropometric dimensions while
designing the interior of truck.
• To modify the dimensions if it is not correct.
• To get realistic feeling from user point of view.
The purpose of arranging tools or features around
the cabin was to minimize the distance of reach for the
driver at the time of driving. The work space was
divided into three zones shown in figure 12, for the
above purposes as:
Primary work zone - The distance from elbow to
hand. This zone includes things those one touches on a
daily basis.
Fig. 11 Various human postures
Secondary work zone - Within arms reach. This
zone is used to position those items those one uses
frequently, but not all the time.
Reference zone - Outside of arms reach. This zone
is use for least used items.
After setting the work zones, it was clearly known
which feature come in primary zone, secondary zone
and reference zone. Features such as steering, switches,
gear, mobile etc. which are used by the driver

frequently come in the primary zone. Other features
such as AC control, audio system, cup holder, etc. come
in secondary zone.
Remaining features which are not used regularly
comes in reference zone.
Table 1 Indian anthropometric dimension
Sl.
No
Parameters
Percentile Design
Method5th
50th
95th
A Normal Sitting 757 819 893 ED
B Eye 678 738 805 AD
C Lower Lumber 72 101 156 AD
D Mid Shoulder 510 576 634 AD
E Elbow Rest 158 213 270 AdD
F Knee 472 519 567 ED
G
Vertical upward
arm reach from
mid shoulder
623 701 774 D
H Popliteal 380 425 471 AdD
I
Buttock to
Popliteal length
399 455 512 AdD
J
Vertical upward
area reach from
seat surface
1199 1315 1414 D
K
Vertical upward
arm reach from
floor
1611 1713 1821 D
L
Buttock to leg
length
640 719 779 AD
M
Buttock to
extended leg
comfortable
length
758 923 1086 D
N Bi-deltoid 379 426 482 ED
O Waist 216 259 317 ED
P Span 1549 1684 1829 D
Q
Upper position
length
469 629 799 D
R
Mid position
length
749 849 939 D
S
Lower position
length
419 599 769 D
T
Upper position
length stretched
839 1099 1399 D
U
Mid position
length stretched
1069 1349 1619 D
V
Lower position
length stretched
879 1129 1439 D
W
Grip inside
diameter,
maximum
42 49 56 AD
X
Hand breadth
with thumb
86 99 111 AD
Y
Hand breadth
without thumb
72 81 90 AD
Z Hand length 163 180 198 AD
AD - Average Design ED – Extreme Design
AdD - Adjustable Design D - Design for 5th
Percentile
9. CONCEPT GENERATION
Concepts were generated by observing and
collecting data of truck interior style since late 1980’s.
Interiors of other vehicles were also considered. Shape,
texture, fabric, color etc. were the major areas while
generating the concepts. Each feature was separately
designed and finally all were merged together (figure
13, 14, 15, 16, 17& 18).
Fig. 12 Work zones
Fig. 13 Concept 1
Fig. 14 Concept 2
Fig. 15 Concept 3

Fig. 16 Concept 4
Fig. 17 Concept 5
Fig. 18 Seat concepts
10. HUMAN ACTIVITY ANALYSIS
Different Positions of a manikin inside the cabin
are shown in the picture below:
Fig. 19 Manikin sitting positions
Fig. 20 Manikin sitting backside
The figure 19 shows the driver in sitting position
while driving. The manikin, that was chosen for the
analysis is of 50th percentile. The data those were
considered are of Indian anthropometric data. Two
people can sit in the back side of the cabin as shown in
the figure 20. The upper berth can be folded at that time
and thus four people can sit in the cabin including
driver.
The figure 21 shows the sleeping position of the
people in the cabin. Arrangement for sleeping is made
for two people. There are two berths, lower berth and
upper berth. The upper berth is hold by chain hanging
from the top.
Fig. 21 Manikin sleeping position
10.1 Vision Analysis
It is important to have clear comfortable vision at
the time of driving. One needs to be able to judge
distances, read road signs, look at the rear view mirror
and traffic lights. Also one must responds to changes in
environment quickly and efficiently.
Fig. 22 Vision window
The figure 22 shows the binocular vision of a truck
driver. The middle zone represents the line of sight. It is
clear from the analysis that the instrument panel and the

rear view mirror are within the line of sight of driver.
So it is concluded that the position of instrument panel
and the rear view mirror is correct dimensionally in the
design. Instrument panel can be clearly seen through the
steering frame in the new design. This indicates that the
display system within the driver’s field of vision is not
obstructed by the steering wheel.
10.2 Reach Analysis
A reach envelope is a three dimensional surface
that represents all the possible positions of the required
features the manikin can reach using only the arm and
forearm. The blue color zone in the figure 23 represents
the reach envelops of left arm and right arm of the
driver.
The figure 23 represents the reach of right hand of
driver. The reach envelop indicates that the right hand
of driver can reach all the controls on the door and
switches on the right side of dash board. The figure 23
represents the reach of left hand of driver. The reach
envelop indicates that the left hand of driver can reach
all the controls such as AC control panel, audio system,
mobile, cup holder, gear etc.
Fig. 23 Right and left hand reach
11. VALIDATION OF FINAL CONCEPT
Design of interior according to the exterior (figure
24) is a good trend in automobile industry. The same
idea was followed in this project also.
Fig. 24 Concept truck exterior
The figure 25 shows the sectional view of the truck
cabin; this gives clear idea of exterior and interior of
truck cabin. The interior matches with the exteriors to
create a sense of New Modern Style in design.
Fig. 25 Truck cabin section
At the time of designing the interior, the focus was
kept on the positioning of the features, fabrics, colour
combination, feature colour based on their functionality.
Fig. 26 Truck interior front side
Fig. 27 Truck interior view
Figure 26 & 27 show the interior design of the
cabin of truck. The interior gives a spacious feeling.
The dimensions of the cabin were according to Indian
standard. Dark blue and yellowish cream colours were
chosen for the interior. It creates a high contrast in the
composition. The light cream colour adds the softness
to the strong masculine effect of dark blue to create the
modern look of the interior.

Fig. 28 Truck interior back side
At the back of the cabin there are two berths for
sleeping as shown in the figure 28. The upper berth is
hold by chain. One water storage tank was installed at
the bottom left hand side of lower berth for general
usage. At the right hand side there were vertical storage
compartments for keeping the belonging of driver. Also
there is a first aid box and drinking water can at the
right side as shown in figure 27. At the bottom of right
hand side there is a compartment to store cooking
utensils. Thus all the basic features were provided in
this design.
12. CONCLUSION
The interior design of truck cabin gives the feeling
of home interior. The New Modern Style was
introduced in this interior design with simple straight
line composition and a combination of dark and light
colours.
Some of the basic facilities were provided in this long
haul truck cabin according to the demand of Indian life
style of drivers for their comforts.
All the ergonomic consideration were included in
design and validated by software analysis.
The future scope of the design can be in the
direction of eco-friendly material and sustainable
manufacturing.
REFERENCE
[1] Dalela, S. (1999). Text Book of Work Study and
Ergonomics. University of Roorkee, Roorkee. 5th
Edition.
[2] Hedge, A. (2000). RULA Assessment worksheet.
Cornell University. Ithaca, NY.
[3] Bots, H., Buffinga, J. (2000). Design Patterns in
Automotive Design: A Behavioral Study. Technical
Report IDE 350.
[4] Mangus, R., Taylor, D. (2005). Auto Interiors.
California Bill‘s. 2nd Edition.
[5] Chakrabarti, D. (1997). Indian Anthropometric
dimensions for Ergonomic Design Practice.
National Institute of Design, Ahemdabad.
[6] Reed, M. P. (2007). Driver and Passenger
Ergonomics. PhD Report. The University of
Michigan. Ann Arbor. Michigan.

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