Road Accident

Contributory

Factors

Svensson (1998):

Driving situation involving one or more

vehicle(s) where road users are unable to

react in a timely manner to avoid an impact.

Definition :

Road Accidents

L. R. Kadiyali (2005):

Accident (collision, overturning or

slipping) which occurred or originated on

a road open to public traffic resulting in

either injury or loss of life, or damage to

property, in which at least one moving

vehicle was involved.

Definition :

Road Accidents

A deadly road accident happened at about 5.45am.

2 male died while another 2 male & 1 female reported

in serious injury. (total of 5 victims)

According to the source, the car hit the tree &

then cannon into a opposite driving lane. When

the rescued personel arrived, 4 victims were still

inside the car & 1 male body found on the road.

The driver was confirmed dead when arrived in

the hospital while 3 others were in serious condition.

Fatal accident news !!

Subject is complex !

Accidents affected by various factors.

Characteristics

of Road Users

Vehicles performance

Roadway & environment

CASE STUDY:

“ A car driver knocking down a school child “

Car driver:

Speeding?

Driving recklessly?

Alcohol / drugs?

Vehicle :

Driver may brake but mechanical failure of brakes?

Slippery conditions due to tyre tread

conditions?

Roadway :

Geometry deficient?

Road surface slippery due to soft aggregates surfacing course?

Thick film of water by rain?

Interaction of diverse set of factors

causes accidents,

though ONE factor may be more

responsible than the rest

& can be easily identified.

Generally,

THREE Categories

of Contributory Factors.

Accident Contributory Factors

Human

Vehicle

Road Environment

60 %

3 %

3%

5%

2%

2%

25%

Carsten et al.(1989):

A road user or traffic system failure

without which the accident

would not have happened.

Definition :

Road Accidents Contributory Factor

Human Factors

Complicated. Sometimes characterised “unscientific”.

Mostly because of motorist & pedestrian

behaviour.

Human factors

Human elements in charge of vehicle:

• Drives,

• Steer,

• Accelerates,

• Decelerates,

• Brakes/Stop.

Human factors

Study of human behaviour offers very

deep insight into causes of accidents.

Provides valuable guidance for avoidance

of accidents.

Human factors

“Behaviour influences & controls

the vehicle

But

Behaviour is controlled by

personality & attitudes”

Human factors

Human Error?

1) Perceptual errors

Critical information might be

below the threshold for seeing

(the light was too dim, the driver was blinded by

glare, or the pedestrian's clothes had low contrast)

Or the driver might make a perceptual misjudgment

(a curve's radius or another car's speed or distance).

Human factors

2) Focus errors

Critical information might be detectable but that the

driver fail to attend/notice because his mental

resources are focused elsewhere.

Often times, a driver will claim that she/he did not

"see" a plainly visible pedestrian or car.

This is entirely possible because much of our

information processing occurs outside of

awareness.

Human factors

3) Response errors

The driver may correctly process the information but

fail to choose the correct response

("I'm skidding, so I'll turn away from the skid"),

or make the correct decision yet fail to carry it out

("I meant to hit the brake, but I hit the gas.”)

Human factors

Human Conditions ?

Human factors

1) Physical / Physiological

~ alcohol/drug impairment,

~ reduced vision,

Human factors

2) Mental / Emotional

~ emotionally upset,

~ pressure or strain,

~ in-hurry.

Human factors

3) Experience / Exposure

~ driver inexperience,

~ vehicle unfamiliarity,

~ road over-familiarity,

~ road / area unfamiliarity.

Human factors

Some list of human factors causing accidents:

• Following front vehicle too closely

• Dangerous cornering

• Dangerous overtaking

• Over speeding

Human factors

• Handphone while driving

• Red light running

• Non-compliance at stop signs

• ??

Human factors

Road Environmental

Factors

Can be developed into

different factors &

not necessarily mean directly

contributing to accident.

Roadway Environmental factors

Examples :

• Inadequate signs & signals,

• View obstructions,

• Design problems:

~ vertical / horizontal alignment,

~ superelevation,

~ carriageway width,

~ width & condition of shoulders.

Roadway Environmental factors

Examples (cont.) :

• Maintenance problems,

• Pavement surface,

• Rapid weather change,

• Ambient vision limitations,

• Access points,

• Roadside hazards,

• ??..

Roadway Environmental factors

Vehicle Factors

1) Vehicle types

2) Vehicle conditions

Vehicle factors

1) Vehicle Types “crashworthiness”

No vehicle is perfectly safe…

Researcher constantly hunt for

improving quality of crash compatibility for

motor vehicles

Vehicle factors

2) Vehicle Conditions “roadworthiness”

Maintenance-related failures:

~ inadequate tyre tread depth, ~ worn brakes, ~ unchecked or unchanged vehicle fluids, ~ under/over inflated tyres, ~ etc…

Vehicle factors

Haddon Matrix

These are

important components of

integrated road safety

strategies !!

Haddon Matrix PRE-CRASH CRASH POST-CRASH

HUMAN •Training,

•Education

•Enforcement

~Driver Training Program &

Grading of Driving Institutes

~RSE in schools

~Publicity Campaign

~CBP (Visibility Enhancement

Materials VEM, Helmets, RSE,

Belts)

~AES

Compliance and

Correct Use of Primary

Safety Features

~wear SIRIM MS1:2011

Protective Helmets &

Visor

~wear seatbelt

•Emergency medical

services

•Skills of Paramedics &

First Respondents

VEHICLE •Primary safety (vehicle stds &

roadworthiness)

~C&U eg . WP29

~NCAP Ratings

~Rear Seatbelts

~HV Under Run

~Vehicle Inspection

•Secondary safety

(vehicle & rider impact

protections)

~airbags, helmets,

panel pad, etc)

~crash compatibility

•Ease of evacuation

Better rescue tools

ROAD

ENVIRO

•Road eng. Programs

~Road Safety Audit

~Blackspot Treatment

~Motorcycle Lanes

~iRAP

•Roadside safety

~forgiving roadside

furniture (e.g. crash

cushions)

~clear zones

•Restoration of roads &

traffic devices

From traffic engineering viewpoint?

Since DRIVER is the KEY,

traffic engineers must be aware of human factors

& realise that traffic engineering

applications & countermeasures

work thru’ their influence on human behaviour.

(Ogden, 1990)

End