Chapter Crashworthiness Pedestrian Safety 4.pdf

Crashworthiness

Pedestrian Safety

1. Chapter 4
PEDESTRIAN SAFETY AND
ERGONOMICS

2. Topics to be covered
•Pedestrian safety
•Importance of ergonomics in automotive safety
•Location of controls
•Anthropometry
•Human impact tolerance
•Determination of injury thresholds
•Severity index
•Study of comparative tolerance
•Study of crash dummies

3. Pedestrian Categories
Pedestrian type Description Relative risk factorSource
Young children Approximately about 21% road traffic death involves
young children
Very high Barton and
Shwebel(2007)
Young adult For fifteen to twenty-one-year-olds. Pedestrian fatalities
are the leading cause of death
Above average Hilton (2006)
Male pedestrian Males are overrepresented in pedestrian fatalities in
most, but not in all studies
Above average Goren et al (200s)
Gender roles Women and girls in low income countries walk more and
transport more house hold goods than male
counterparts increasing their risk as pedestrian.
Above average Roy (2009)
Elderly The elderly have the highest risk of mortality of all
pedestrians when involved in vehicle collision
Very high Nagar (2010)
Low socioeconomic
status
A strong inverse relationship is found between socio
economic status and risk of pedestrian injuries and
fatalities
High Azetsop(2010)
Intoxicated or distracted
pedestrians
Intoxication and distraction from devices put
pedestrians at a higher risk of injuries and fatalities
High Wener(2008)
Disabled pedestrianVisually impaired pedestrians are at elevated riskHigh Xiang et al (2006)
Pedestrians in low
income countries
Are vulnerable to injuries and death from car collisions.
Attributable to increased urbanization and motorization.
Above average Bishairet al (2006)

4. Con..
•Though pedestrian is the most important constituent of traffic, he/she belongs
to high risk group on road.
•In order to remain safe from perils of road, pedestrians should cultivate the
habit of using road infrastructure in proper manner.
•Subways, zebra crossings, foot over bridges should be used to cross the road.
•Short cuts and easy options of crossing roads are dangerous and should not
be resorted to.

5. Con…
•Simple actions on road will keep you safe
•Walk with care and with all sense
•Look towards oncoming traffic
•Never assume driver has seen you when you are about to cross road. It is your
responsibility to save yourself.
•Avoid crossing road where drivers may not be able to see you
•Wait for suitable gap in the traffic flow before crossing the road.
•Never jump over the divider railings. You may tumble on to the traffic.
•Always hold hand of children while crossing the road.
•Avoid using roads for morning walks and jogging.
•Take extra care if you have to cross the road on or near a crest or curve.
•Avoid crossing road between parked cars.
•Crossing road by the shortest and most direct route reduces your time on road.

6. Con..
•Children are more susceptible to the dangers of road. It is not solely
the drivers of the vehicles who cause accidents but carelessness of
children and lack of awareness which add up the cause of accidents
on road.
•Teach your child to walk on footpath, encourage him/her to use
subways, zebra crossing etc.
•If you will do the right thing on road, your child will follow you and
will remain safe in traffic.
•To cross the road children should learn following:
•Stop at the kerb
•Look at your left, right and left again.
•Ensure that no vehicle is approaching
•Then walk across the road

7. Ergonomics
•The word “Ergonomics” originated from two Greek words “Ergon” means “work”
and “Nomos” means “natural laws”
•Ergonomics (or human factors) as the scientific discipline concerned with the
understanding of interactions among humans and other elements of a system,
and the profession that applies theory, principles, data and methods to design in
order to optimize human well-being and overall system performance.
•Ergonomics is concerned with the health of the people and the productivity of the
system.
•It is to get proper fit between people and their technological tools and
environments.
•Disctionariesgenerally define ergonomics as a scientific discipline that uses
principles of biotechnology and engineering to make products more comfortable
for workers and consumers. But, ergonomics isn’t just about design. It also factors
in how we use things.

8. Domains of Specialization:
According to international Ergonomics Association (IEA) ergonomics
can be broadly classified into:
•Physical Ergonomics
•Cognitive Ergonomics
•Organizational Ergonomics

9. Physical Ergonomics:
•It is concerned with human anatomical, anthropometric, physiological
and biomechanical characteristics as they related to physical activity.
•Relevant topics may include:
•working postures,
•material handling,
•repetitive movements,
•work related musculoskeletal disorders,
•workplace layout,
•health and safety.

10. Cognitive Ergonomics:
•A proper fit of a product to a user does not end with physical
interfaces.
•Cognitive / perceptual ergonomics is concerned with mental
processes, such as perception, memory, reasoning, and motor
response, as they affect interactions among humans and other
elements of a system.
•Relevant topics include mental workload, decision-making, skilled
performance, human-computer interaction, human reliability, work
stress and training as these may relate to human-system and Human
computer interaction design.

11. Organizational Ergonomics:
•It is concerned with the optimization of socio technical systems,
including their organizational structures, policies, and processes.
•Relevant topics include,
•crew resource management, and work design,
•design of working times,
•teamwork, community ergonomics, cooperative work,
•new work programs,
•virtual organizations, telework, and quality management.

12. Ergonomics in Automotive Safety
•Ergonomics plays a crucial role in automotive safety by optimizing the design of
vehicle interiors and controls to enhance comfort, usability, and safety for drivers
and passengers.
•There are five aspects of ergonomics:
•Safety
•Comfort
•Ease of use
•Productivity/performance
•Aesthetics

13. Ergonomics is important in:
Reducing Driver Distraction:
▪Well-designed vehicle interiors and controls minimize driver distraction by placing
essential functions within easy reach and ensuring intuitive operation.
▪Ergonomically positioned controls, such as steering wheels, pedals, and gear shifters,
enable drivers to maintain focus on the road while accessing vehicle functions,
reducing the risk of accidents caused by distracted driving.
Enhancing Driver Comfort and Fatigue Reduction:
•Ergonomic seating designs provide proper support and adjustability to accommodate
a wide range of body types and driving preferences.
•Comfortable seating reduces driver fatigue during long journeys, promoting alertness
and attentiveness behind the wheel, which is essential for safe driving.

14. Con…
Improving Visibility and Sightlines:
•Ergonomically designed vehicle layouts optimize sightlines and visibility, allowing drivers to
have clear views of the road and surrounding traffic.
•Properly positioned mirrors, windshield wipers, and instrument clusters minimize blind spots
and enhance situational awareness, reducing the likelihood of accidents due to obscured
vision.
Facilitating Safe and Efficient Operation:
•Ergonomic control layouts ensure that essential functions are easily accessible and operable
without requiring the driver to take their eyes off the road or hands off the steering wheel.
•Intuitive interfaces and tactile feedback help drivers navigate vehicle controls confidently and
efficiently, enhancing overall driving safety.
Accommodating Diverse Users:
•Ergonomic design principles take into account the needs of diverse users, including drivers of
different ages, sizes, and physical abilities.
•Adjustable features such as steering wheel tilt and telescoping, seat height and lumbar
support, and pedal positioning accommodate individual preferences and ensure a comfortable
and safe driving experience for all users.

15. Con..
Minimizing Injuries in Crashes:
•Ergonomically designed vehicle interiors and restraints help minimize the risk of
injury in the event of a crash by properly positioning occupants and distributing
impact forces.
•Features such as adjustable headrests, seat belts with pretensioners and force
limiters, and airbag deployment systems are engineered with ergonomic
considerations to provide optimal protection during collisions.
Enhancing User Experience and Satisfaction:
•A well-designed interior that prioritizes ergonomics contributes to overall user
satisfaction and enjoyment of the driving experience.
•Ergonomically optimized vehicles are easier and more comfortable to drive, fostering
positive associations with the brand and encouraging repeat business.

16. Vehicle ergonomics continued
•Prolonged periods of sitting can place heavy demands of our posture, particularly when
sitting in a vehicle due to added affects of movement and vibration on the body.
•Being comfortable and well positioned in a vehicle aims to reduce driver fatigue and the
development of musculoskeletal disorders.
•It is imperative that everyone using a vehicle for work observes adequate ergonomic
requirements to minimize the risk of injury.
1.Seat height
•Raise the seat to ensure the driver has maximum vision of the road
•Ensure there is adequate clearance from the roof
2. Lower limb position
•Knees should be bent, in order to comfortably operate the accelerator/clutch and brake.
•The steering wheel should not come into contact with the top of the legs
3. Seat pan
•Thighs supported along the length of the cushion.
•Avoid pressure behind the knees
4. Back rest
•Adjust the back rest so it provides continued support along the length of the back.
•Shoulders slightly behind the hips.

17. Con…
5. Lumber support
•The lumbar support whether adjustable or not, should provide comfort with no
pressure points or gaps between the spine and car seat. A S-shape spine is a safe
shape.
6. Steering wheel
•All objects and controls should be in easy reach to prevent unnecessary reaching.
•Elbows and shoulders should be in a relaxed position with hands positioned below
shoulder level.
•Check for clearance of thighs and knees (allow 2-4 cm)
•Ensure display panel is in full view and not obstructed
•A good test is to put your arms straight in front (above the top of the steering
wheel), the top of the wheel should sit at approximately wrist level.
7. Headrest
•The neck should be in a neutral position, with the headrest positioned centrally
behind the head.
8. Mirrors
•Adjust the rear view and side mirrors to ensure adequate vision of surrounding areas

18. Con…
Criteria for a driver seat:
1.The set should position the driver with
unobstructed vision and within reach
of all vehicle control
2.The seat must accommodate the
driver’s size and shape
2. The seat should be comfortable for
extended period
4. The seat should provide a safe zone for
the driver in a crash

19. Con…
•Ergonomic Aspects in automobile Design
•Visual aspect
•Air bag warnings
•Comfort, usability seat belt
•Collision avoidance system
•Traction control system
•Brake assist system
•Navigation system
•Vehicle interior, controls, pedals etc
•Reach to advanced recreational systems
•Common driving injuries
•Foot cramps are the most common repetitive driving injury
•Followed by back pain
•Neck stiffness
•Side ache and eye strains, which often lead to headaches

20. Placement of vehicle controls
•Vehicle controls constitute an essential part of ergonomics.
•From cars with push button ignition like many Toyota models, notably the
Prius –to power seats , automatic headlights, automatic climate control and
electronic parking brakes, the latest in ergonomic innovation is often
characterized by automation and ease of use.
•These features are, notably, easier for disabled drivers to use and allow many
drivers to simply set a goal, such as a desired temperature of 72 degrees
Fahrenheit (22 degrees Celsius), and the car does the rest.
•One of the more intriguing trends in ergonomic design is the attention now
paid to older drivers.
•All types of cars –including sports cars –are now being designed to have
controls with larger text and better lighting to maximize readability,
particularly for older or functionally disabled drivers.
•Even door handles are being made to allow a better grip for people with
conditions like arthritis.

21. Con…
•To design controls suitable for older or even for pregnant, some auto engineers
put on suits that limit their mobility and range of vision or that come with a
large belly, mimicking pregnancy.
•This flexibility means that an engineer can easily test how a certain control
configuration might be used by a 6-foot, 200-pound man or a 5-foot, 120-
pound woman –and everyone in between. These programs also allow for
testing for people with disabilities, usual body types or special needs.
•Distracted driving is a major concern, leading many to pass laws regulating
drivers’ cell phone use.
•At the same time, more cars are coming equipped with integrated hands free
phone systems, often incorporating Bluetooth. But the challenge then arises of
how to make this system accessible and easy to use without distracting drivers
or requiring them to take their eyes off the road.
•There’s some speculation that future cars will need to rely more on audio/voice
controls, a feature that exists to a limited extent in some vehicles.

23. Anthropometry
•Anthropometry refers to the measurement of the size and proportions of the
human body. While the architects of the renaissance saw the proportions and
the human figure as a reaffirmation that certain mathematical ratios reflected
the harmony of their universe, anthropometric proportional ones. These
ratios are predicted based on the theory of: “architecture space is either
container or extension of the human body and some relevant activities,
therefore should be determined by its dimensions”.

24. Anthropometry
•H-Point(Hip point) is the theoretical, relative location of an occupant’s hip, specifically the pivot point between
the torso and upper leg portion of the body, either relative to the floor of the vehicle or relative to the height
above pavement level. Technically the measurement uses the hip joint of a 50
th
percentile male occupant,
viewed laterally.
•B-Point(seating reference point) is the theoretical hip point, used by manufacturers when designing a vehicle
and more specifically describes the relative location of the sealed dummy’s hip point, when the seat is set in
the rearmost and lowermost seating position.

25. Con…
•The seat of the vehicle must be designed as such to enable maximal comfort
for the driver how for short, so and for long journeys, with minimal fatigue.
•The seat comfort directly influence on inconvenience in the neck area, upper
back and knees.
•Besides that, the driver first must to set up the seat how is convenient for him,
and that doesn’t disturb:
•Proximity of the driver to the accelerator pedal, brake pedal, steering wheel and
instrument panel controls;
•Head and leg room, and
•Field of vision.
Influence of Anthropometric Dimensions on Pedals Activation Force and On H-Point
Position. Available from:
https://www.researchgate.net/publication/337318431_Influence_of_Anthropometric
_Dimensions_on_Pedals_Activation_Force_and_On_H-Point_Position[accessed May
07 2024].

26. Siting Angle Defining
•The body angle is defined in respect to the vertical line, While other
angles are specified in respect to the body.
•The great number of organizations, as well as researchers has worked
on finding the ideal siting angle in the passenger car.
•For further analysis in the paper, the siting angle is defined by
recommendations of the RAMSIS

27. Posture-defining joints

28. Topology
•The software package used for comfort analysis is RAMSIS. Analysis
is conducted for American male population, with basic dimensions
(body height, waist circumference and sitting height for population
from 1 – 99%.
Dimensions for the male population

29. Vehicle Occupant packing
•Definition and importance of vehicle occupant packing
• Key vehicle dimensions and reference points associated with occupant packing
•Sequence and development procedure of vehicle packing
•SAE standards which are relevant to occupant packing and ergonomics
evaluations are listed below. The corresponding international standards (ISO)
and British standards (BS) are given in parenthesis (porter and porter, 2002)
•SAE J826 H-point (ISO 6549)
•SAE J1100 seating reference point
•SAE J1517 Driver selection seat position
•SAE J941 Eyellipse (ISO 4513/BS AU 176)
•SAE J1052 Driver and passenger head position contours
•SAE J287 Hand controls each envelopes (ISO 4040/Bs AU 199)
An eyellipse is a statistical representation of driver eye locations used to facilitate the design and evaluation of vision in motor vehicles

30. What is Occupant packing?
•The term packing was introduced in automotive industry to indicate
the process os assembling vehicle components (sub-systems) within
the allocated/planned 3D space or volume of the vehicle to ensure
functionality and usually of the vehicle.
•The occupant packing is defined as the 2D or 3D representation of
occupant e.g. drivers and passengers in relation to vehicle
components and layout.

37. Assignment 3
•Prepare a short PPT note on:
VEHICLE SAFETY SYSTEMS
•Survival space requirements, restraint system used in Automobiles, types of safety belts, regulations,
automatic seat belt tightener system, collapsible steering column, tiltable steering wheel, air bags, electronic
system for activating air bags, bumper design for safety, antiskid braking system, regenerative braking
system, speed control devices.
•Maximum 30 slides.