This document summarizes an accident study report prepared by students. It outlines the objectives of accident studies which are to study causes of accidents and suggest corrective measures. It then discusses the common causes of road accidents which include road users, vehicles, road conditions, and environmental factors. It also describes common accident types and how accident data is analyzed through reports, records, and diagrams. Finally, it discusses performing statistical analysis of accidents and examples of calculating different accident rates, and lists several safety measures that can be taken through engineering, enforcement, and education.

1. University of Duhok
College of Engineering
Civil Department
Prepared By :
Jameel Masoud & Rajab Othman
2019-2020
Accident Study

2. Content List
 Introduction
 Objective of Accident Studies
 Cause of Road Accident
 Common Type of Accident
 Accident Analysis
 Statistical analysis of accidents
 Safety Measures

3. The traffic engineers have to undertake a big responsibility of providing safe traffic
movements to the road users and ensure their safety. Road accidents cannot be totally
prevented but by suitable traffic engineering and management the accident rate can be
reduced to a certain extent. For this reason systematic study of traffic accidents are required
to be carried out. Proper investigation of the cause of accident will help to propose
preventive measures in terms of design and control.
Introduction

4. • To study the causes of accidents and suggest corrective measures at potential location.
• To evaluate existing design.
• To compute the financial losses incurred.
• To support the proposed design and provide economic justification to the
improvement suggested by the traffic engineer.
• To carry out before and after studies and to demonstrate the improvement in the
problem.
Objectives of accident studies

5. 1) Road Users:
Causes of road accidents
a) Driver: age of driver, fatigue, over speed, rash
driving, carelessness, violation of rules and
regulation.
b) Pedestrian: carelessness and lack of awareness.
c) Passenger: boarding and DE boarding of moving
vehicles.

6. a) Braking system.
b) Vehicle lighting system.
c) Vehicle body and its features
d) mirrors and tyres.
e) Vehicle inspection and maintenance.
Causes of road accidents
2) Vehicle :

7. Causes of road accidents
3) Road Condition and Design :
a) Friction between the tyre and surface.
b) Sight distance
c) Adequate super elevation
d) Carriageway width.
e) Deficiency in road signs and markings
f) Junction design
g) Narrow bridges and culverts
h) Median
i) Street lighting.

8. unfavorable weather conditions like mist, snow, smoke and heavy
rainfall which restrict normal visibility and makes driving unsafe.
Causes of road accidents
4) Environmental Factors:

9. Side-Impact Collision
Common Accident types
Head-On Collision
Rear-End Accident
Single Car Accident

10. a) General - Date, time, person involved in accident, classification of accident.
b) Location.
c) Details of vehicle involved.
d) Nature of accident.
e) Road and traffic condition.
f) Primary causes of accident.
g) Accident cost.
Accident analysis
1) Collection of Accident Data :

11. a) Accident should be reported to police authorities.
b) Accident report is useful in subsequent analysis, claim for compensation ,
evaluation of cost, etc…
2) Accident report :
Accident analysis

12. 3) Accident Records :
Accident analysis
a) Condition Diagram :
It is the diagram showing all
the physical conditions of an
accident location to be
studied.

13. This diagram shows the
approximate path of vehicles and
pedestrians involved in the
accidents.
3) Accident Records :
b) Collision Diagram :
Accident analysis

14.  The statistical analysis of road accidents help to asses the
effectiveness of various measures to decrease the accident rate .
 The accident rate may be expressed as no. of accidents in a year.
 Accident prone stretches of different roads may be assessed by
finding the accident density per unit length of the road.
Statistical analysis of accidents

15. Accident Rate per Kilometer :
On this basis the total accident hazard is expressed as the number of accidents
of all types per km of each highway and street classification.
𝐑 =
𝐀
𝐋
R = total accident rate per km for one year.
A = total number of accident occurring in one year.
L = length of control section in kms.
Statistical analysis of accidents

16. Accident involvement Rate :
It is expressed as numbers of drivers of vehicles with certain characteristics who
were involved in accidents per 100 million vehicle-kms of travel.
𝐑 =
𝐍 × 𝟏𝟎𝟎 × 𝟏𝟎 𝟔
𝑽
R = accident involvement per 100 million vehicle-kms of travel.
N = total number of drivers of vehicles involved in accidents during the
period of investigation.
V = vehicle-kms of travel on road section during the period of investigation
Statistical analysis of accidents

17. Death rate based on population :
The traffic hazard to life in a community is expressed as the number of traffic fatalities
per 100,000 populations. This rate reflects the accident exposure for entire area.
𝐑 =
𝐁 × 𝟏𝟎𝟎 × 𝟏𝟎 𝟑
𝐏
R = death rate per 100,000 population.
B = total number of traffic death in one year.
P = population of area
Statistical analysis of accidents

18. Death rate based on registration :
The traffic hazard to life in a community can also be expressed as the number of
traffic fatalities per 10,000 vehicles registered. This rate reflects the accident
exposure for entire area and is similar to death rate based on population.
𝐑 =
𝐁 × 𝟏𝟎 × 𝟏𝟎 𝟑
𝐌
R = death rate per 10,000 vehicles registered.
B = total number of traffic death in one year.
M = number of motor vehicles registered in the area
Statistical analysis of accidents

19. Accident Rate based on vehicle-kms of travel :
The accident hazard is expressed as the number of accidents per 100 million vehicle
km of travel. The true exposure to accident is nearly approximated by the miles of
travel of the motor vehicle than the population or registration.
𝐑 =
𝐂 × 𝟏𝟎𝟎 × 𝟏𝟎 𝟔
𝐕
R = accident rate per 100 million vehicle kms of travel.
C = number of total accidents in one year.
V = vehicle kms of travel in one year
Statistical analysis of accidents

20. The Motor vehicle consumption in a city is 8000 million liters, there were 4500
motor vehicle fatalities, 500,000 motor vehicle injuries, 10,000,000 motor vehicle
registrations and an estimated population of 25,000,000. Kilometer of travel per
liter of fuel is 18 km/liter. Calculate population death rate, registration death rate
and accident rate per vehicle km ?
Statistical analysis of accidents
Example

21. Statistical analysis of accidents
Solution 1- Population Death Rate :
R =
B × 100 × 103
P
=
4500 × 100 × 103
25 × 106
= 18
2- Registration Death Rate :
R =
B × 10 × 103
M
=
4500 × 10 × 103
10 × 106
= 4.5

22. Statistical analysis of accidents
3- Accident Rate Per Vehicle km :Solution
Approximate vehicle km of travel = Total consumption of fuel × kilometer of travel per liter of fuel
= 8000 × 106
× 18 = 144 × 109
km
R =
C×100×106
V
=
4500×100×106
144×109 = 3.13

23. Safety measures
- Visual guidance to driver
- Road reconstruction
- Channelization
- Road signs
- Other methods
- Street lighting
- improvement in skid resistance
- Guard rail
- Speed control
- Training and supervision
- Medical check
- Education of road users
- Safety drive
Engineering
EnforcementEducation