The Social and Environmental Effects of Hydraulic Fracturing in the United St...
Final Report
1. 1
Final Report
An Investigation of Concrete Trucks’ Safety and
Accidents
Prepared by Feng Mai (200 314 281)
External Supervisor: Dr. Hamid R. Soleymani (Ministry of Highways and Infrastructure)
Internal Supervisor: Dr. Satish Sharma (University of Regina)
Date: April 1st , 2014
2. 2
Executive Summary
The ready mixed concrete refers to concrete that is specifically manufactured for
delivery to the customers’ construction sites in a freshly mixed and plastic or
unhardened state. Nowadays, the concrete is the most widely used manufactured
material in the world. As the significantly high demands for the ready mixed
concrete, the transportation of the concrete became an importation concern.
Currently, the major method for ready mixed concrete transportation is the
concrete mixer truck. However, during the transportation, the concrete trucks are
involved in many road accidents. The U.S. department of transportation indicated
that over 3,500 large truck accidents (including concrete trucks) happened in 2013.
A study titled “Investigation of the concrete truck safety and accidents” was
launched in fall 2013 and this aimed to investigate the major contributing factors in
concrete mixer truck in North America by using more than 200 accident records all
around the world.
The majority of the accident cases that have been introduced in this project were
gained from aggregate industrial website and U.S. department of Labor. The
accidents cases occurred in many countries, however, over 80% of the accidents
that analyzed in the project database were from North America.
3. 3
Several possible contributing factors were identified at beginning of the project
includes speeds, loads, visibility and other factors in concrete truck accidents.
Analysis also combined with theoretical calculations include two scenarios, one was
the concrete truck was fully loaded and the other was empty concrete truck. The
theoretical analysis was mainly focused on the roll over of concrete truck when it is
curving.
The results of the project indicated several factors such as speed, loading conditions,
and human errors were the main contributing factors in concrete truck accidents.
5. 5
1.0 Introduction
The concrete trucks, which are the transportation trucks for ready mixed concrete
to the construction site, have become a cause of millions of properties loss and taken
hundreds of life in a worldwide range. The high accidents rate of concrete trucks
was the motivation of this project.
The project stated in the fall of 2013 to determined the main contributing factors of
concrete mixer trucks’ safety issues by analyzing the factors that were involved in
more than 200 concrete trucks accidents. The analysis was mainly based on the
statistic analysis, and theoretical calculation was combined. Meanwhile, limited
interview was applied to provide additional information to support the statistic
analysis.
The concrete trucks have some characteristics such as huge weight and high center
of gravity. These factors were not considered in this project. This project was
focusing on the factors that determined has a changes to modified or improved.
However, the center of gravity and weight of the concrete truck were used in the
theoretical calculation to determine effects for other identified contributing factors.
Meanwhile, According to the information provided by U.S. Department of
Transportation, 90% of the large trucks accidents were caused because of human
errors. (Rue, Ziffra n.d) However, it is believed that, some characteristics of the
6. 6
concrete trucks contributing with the human errors lead to concrete truck accidents
happen. In this project, the human error was considered as one potential
contributing factor. The other analyzing factors were focusing on concrete truck
itself and surrounding environmental factors.
The project have been divided into three phases, each of them has a clear objective
to contribute for the whole project. First of all, the literature reviews and Accident
data collection, in this stage of the project the main objective was to review and
collect information regarding to the possible contributing factors for the concrete
trucks accidents. Several research papers and articles were review to generate a
database. Meanwhile, parameters for the theoretical analysis were identified. In the
next phase of the project, the main task was collecting enough accident cases, and
importing them into the database. Besides, by reviewing the information from the
accidents reports and interviews modifications and improvements of database were
accomplished. The last phase of this project was to analyze the factors included in
the database to determine the main contributing factors of the concrete truck
accidents.
At the completion of the project several factors including truck speed and loading
condition were determine as the contributing factors for the concrete truck
accidents.
7. 7
2.0 Scope & Objectives
The main objective for this study was to determine the contributing factors to the
concrete truck accidents in the North America. Some concrete truck’s characteristic
such as weight and center of gravity were excluded. Several factors such as trucks
weight and center of gravity were not considered in this study. However, during the
theoretical calculations the weight and center of gravity were considered. The
methods have been used for this project were based on the statistic analysis
combined with some theoretical calculations.
In order to achieve the main objective, some tasks were defined. These following
tasks were served the project to meet the main objective and to determine the
contributing factors for the concrete trucks accidents.
First of all, the literatures were reviewed for this project were mainly helped to
determine the potential contributing factors for analyzing. Literature review
focused on other researches regarding to the concrete truck or other type of large
loaded trucks. Meanwhile, the literature review also served for the theoretical
calculation. Most of parameters that were used for the analysis extracted from it.
Secondly, the accident data collection process was one of most important processes
in this project. In order to get a relatively accurate result, more than 200 accidents
cases should be used in the databases analysis. Besides, considering that some of the
8. 8
cases may not meet the requirement of the project, the cases collection were
requirement to meet a number that greater than 300 accidents cases.
Finally, the analyzing processes, as indicated in the earlier section the project was
based on the statistic analysis. These analysis processes were lead to the results that
tells the main contributing factors for the concrete trucks accidents. However, some
of the factors may not be able to be determined from the statistic analysis as lack of
input data. The theoretical calculations were the method to apply. For example, the
contributions to the accidents of concrete loading of the trucks were calculated from
the theoretical calculation.
9. 9
3.0 Literature Review
The main purpose for the literature review was providing information to determine
the contributing factors that will be analyze in this project. Meanwhile, it will also be
used to find the important parameters for the theoretical calculations. The literature
reviews were focusing on two areas, including concrete truck accidents and
regulations for the concrete mixer trucks.
3.1 Contributing Factor
According to the article “Construction Tuck Accidents” prepared by the Rue, Ziffra,
P.A. concrete mixers trucks are heavy, industrial vehicles have been using to deliver
concrete to construction sites. (Rue, Ziffra n.d) Generally, the deliver period of
concrete truck is less than 90 minutes after the mixed concrete is loaded. Most
concrete trucks weigh range between 20 and 60 tons and has high center of gravity.
Because the mixed concrete required delivering in 90 minutes or less, the speed of
the concrete truck can be a contributing factor of the accidents. The article also
indicates that the weight of the concrete may has a 35 tons difference between fully
loaded and empty. The huge variation of the weight can have significant influences
when a concrete truck is curving or braking. Whether the concrete mixers were
loaded or empty when the accidents happened was another contributing factor that
has been analyzed in this project.
10. 10
The drivers’ errors, Rue, Ziffra P.A. indicated, “90% of all large truck accidents
(including cement truck accidents) are caused by human error.” (Rue, Ziffra n.d)
The main human factors being:
Driver Fatigue
Driver inexperience or lack of safety training
Driver intoxication
Driver failure to obey traffic laws
Even most of the concrete trucks accidents were caused by the human factors, but it
is believed that, the features of the concrete tuck magnified the human errors. For
this reason, in the analysis of this project, the driver’s miss-operation was only
considered as one potential factor.
Beside the human error, other element that can intensify cement truck accident
includes:
Bad weather (result in low visibility for drivers)
Poor road condition
Vehicle equipment failure (brakes, steering, oil leakage, etc.)
Improperly load or overload
For the accident types of the concrete trucks, these are not a factors that
contributing to the accidents. However, by analyzing the accident types of the
accidents may give indications to which factors are likely to be a contributing factor.
11. 11
According to the article provided by Missouri Truck Accident, the types of accidents
involving concrete trucks can be divided into several categories as follow: (Missouri
Truck Accident n.d.)
Rear-ending
Head-on crashes
Side collision
Multiple truck accidents
Under ride truck accidents
Over-ride truck accidents
Roll-over truck accidents
The accident types can give indications for which factors are more likely to be
contributing factors in concrete truck accidents. For example, the large percentage
of roll over indicated speed and load are likely to contribute to concrete truck
accidents.
3.2 Theoretical Calculation Parameters
The main purpose of theoretical calculation for this project was mainly to determine
if the loading condition and speeding factor are contributing factors for the concrete
truck accidents. Generally speaking the most widely used concrete trucks in North
America have 3 axles with one axle in the front and two on rear configuration. The
theoretical calculation was based on this type of concrete trucks.
12. 12
In order to analyze the force on the concrete truck while it is turing. Some
specifications were requirement to fulfill the calculation. The information in table
3.2.1 was gained from Alibaba n.d., which indicated information of the specifications
of 3 general 6X4 concrete trucks.
Model Truck Weight
(kg)
Maximum Capacity
(m3)
Maximum Speed
(km/h)
SQR3250D6T4-E 14500 11 90
SQR3250D6T4-E3 14200 12 88
SQR3250D6R4-1 15000 13 83
Table 3.2.1 Concrete Trucks Specifications
As table indicated it is easy to determine that the average self-weight for the
Concrete truck is about 14.5 tons. The Maximum Capacity and Maximum Speed are
12 cubic meters and 85 km/hr, respectively.
Weight and Maximum design speed of the concrete truck, but also the dimensions of
the concrete truck were required for the theoretical calculation. Figure 3.2.2
indicated the dimensions of each part of the concrete truck and the weight
distribution on axles.
From Figure 3.2.2 it is easy to see that the height of the concrete trucks with a 6X4
axles configuration is about 3.7 m and the most of the weight was loaded on the rear
axles, only a small portion of the weight is on the front axle.
13. 13
Figure 3.2.2 Dimensions and weight distribution of typical concrete truck (Voice of
Stamford n.d.)
The parameters that collected as descripted above were the static parameters of the
concrete trucks. However, the concrete truck accidents often happened when the
concrete trucks were in motion. In order to calculated the forces acting on the
concrete when it is in motion some dynamic parameters are required.
The center of gravity or center of mass offset is the reason that causes a concrete
truck to roll over from theoretical views. The more offset of the center of gravity
when the concrete trucks were curving, the more likely the concrete trucks to roll
over.
14. 14
According to the researches that done by Beijing Jiaotong University in China, the
center of gravity offset for the loaded trucks (includes concrete truck) are related to
the traveling speed and the mass of the trucks. The figure 3.2.3 shows the trends of
offset of gravity center (y) as speed and total mass change.
Figure 3.2.3 the trends of center of gravity offset (Beijing Jiaotong University n.d.)
With these factors combining with the roadway design standard the force acting on
a concrete truck while it curving can be calculated and analyzed. The detail
calculation will be shown in the section 6.1.
15. 15
4.0 Methodology & Data Collections
As indicated in Section 2.0, the first task for this study was determining the potential
contributing factors for the concrete truck accidents. The primary method for this
task was the literature reviews. Reviewing of other research studies or articles with
regard to the concrete truck accidents helped to determine the factors to be analyze
in this project. Meanwhile, in order to include as many potential factors as possible
for the project analysis, some factors were determined during the accident cases
reviewing and the interviews.
There were 11 factors extracted from the literature review that included:
Truck loading conditions (Fully loaded, partial Loaded, and Empty)
Accident Locations (Construction Zone, City Road, and Highway)
Truck speed at the time of accident (Over-speeding, and Not Over-speeding)
Visibility (Good Visibility and Bad Visibility)
Accident time (Moring, Afternoon, and Night)
Weather Conditions (Sunny, Rainy, and Snowy)
Mechanic Failures (Brake, Suspension, Tires, and Other)
Accident Types (Read-ending. Head-on Crashes, Run-over, and Roll Over)
Damage and Injuries (Property Damage, No. of Injuries, and No. of Fatalities)
Drivers’ Miss-operation
Countries and date of accidents
16. 16
After the literature review, studying reports and interview provide valuable
information for the analyzing factors. First of all, for truck loading condition, for
most of the accident reports were limited. The modification for this factor has been
made and for the loading condition only loaded or empty condition were analyzed.
Meanwhile, by doing the accident reports reviews and interviews some other
factors were introduced into the project that included:
Truck Type (Number of axles)
Blind Points
Backing Up
Slow-Moving
After the completion these processes, 15 potential contributing factors were
determined and the second stage of the project began.
There were two tasks for the second stage of the project. First of all, the cases
collections, in order to ensure the project was using good data both quantity and
quality of the case collections should be investigated
The volume of the accident cases collected for this study was initially 350 accident
cases. The majority of the cases were gained from Aggregate Industrial Website
(ARI: www.aggregateresearch.com) and United States Department of Labor (Osha:
www.osha.gov). The total number of accident cases that collected from these two
17. 17
sources was approximately 270 and 80 accident cases from major media and news
from the Internet were collected
However, at this point, the data collection was not perfect for the analysis. Some
accident cases reported concrete pump trucks accidents rather than concrete mixer
trucks, which were, not meet the scope of the project. Besides, some accident
reports contented extremely limited information was also not meet the requirement
of the project. Also, by comparing the accident report between North America and
other developing countries, some variations of contributing factors were found. In
order to ensure the correct of the final results of the project, some cases that happen
outside of North America requires to be removed from the data collection. After the
filtration process to eliminate the disqualified data, 211 accident cases were
remained in the data collection for this study.
The second task was database design and entering the accident cases into the
database. The database design was based on the potential contributing factors that
had been determined in the first stage of the project. Then, several columns to
indicate the states of the factors were assigned to each factor in an Excel
Spreadsheet. Meanwhile, an identical case ID was assigned to each case for the
further reviews. After the data plotting into it, a 44 columns database was formed A
copy of database is attached in Appendix I.
18. 18
The final stage for this project was analyzing the data from both database and
theoretical calculations. Firstly, the analysis of each factor in the whole database
was completed to illustrate the contributions of each factors made to the concrete
truck accidents. Meanwhile, the theoretical calculation was done to indicate the
speeding and loading factors’ contribution in a theoretical way. The parameters that
collected from the literature review and were used in calculation included weight
distribution on the concrete trucks, center of gravity in different loading conditions,
and the forces acting on the trucks while they were curving in different speeds and
loading conditions.
Secondly, the data were separated into North America cases and other countries to
determine the variations of contributing factors between these to categories. The
purpose of this analysis was to determine the contributing factors for accidents
happened in the developing countries and comparing with the factors in North
America.
19. 19
5.0 Description of Database
In this section, a detail description with regard to the sources, volume, and data
distributions of the project database will be illustrated. Meanwhile, the analyzing
factors in the database will also be mentioned in this section.
5.1 The Basic Information of Database
Because of this project was based on the statistic analysis, the database played a
significant role. In order to ensure the quality of the database, as many as possible
accident cases were introduce in the database and the sources of the data were
verified, either.
Initially, more than 350 accident cases were collected in the year range from 1984
to 2014. The majority of the data were collected from the U.S. government and
aggregate industrial websites. A small percentage of the accident cases were gained
from the major media from different countries. The distribution of the data
collection is shown in Figure
20. 20
Figure 5.1.1 the distribution of data collection
After the data collection process, the data were plotted into the database. The
plotting in process was based on the analyzing factors that are going to be discussed
in the section 6.2. All the accident cases were reviewed and about 90 cases were
removed because of the data not meet the requirement of this project. The removed
data can be separated in to two categories, the first one was that accidents report
indicated other type of concrete truck such as concrete pump truck rather then the
concrete mixer truck involved in. The second one was the information provided by
the report is extremely limited. By doing this filtration process, about 260 data
maintained in the database.
The project database contents the accidents information for multiple countries.
Some of the countries are not located in North America, such as, China, India, and
Australia. In order to meet the scope of the project, the data adjustments have been
done after the data plotting in. Some accident from the developing countries such as
66%16%
18%
Government
Website
Aggregateresearch
News
21. 21
China, and India were removed from the database. The reason for removing these
data from the database was that the regulations and road conditions differ from
most of the North America Countries. These can be a misleading of the true
contributing factors for concrete mixer truck in the North America range. However,
some of the accidents, which have a similar situation in North America, have been
kept in the database. The data adjustment leads to another reduce in the data
volume to 211 but the volume still meet the project requirement. The 211 accident
cases database was made up by 85% from North America and 15% from other
countries. The figure 4.1.2 below illustrated the distribution countries and number
of accidents cases associated with the project database.
Countires No. Of Cases Percentages
U.S. 168 79.62%
China 19 9.00%
Canada 10 4.74%
Australia 6 2.84%
Africa 1 0.47%
Lebanon 1 0.47%
Nigeria 1 0.47%
India 1 0.47%
Singapore 1 0.47%
Total 211 100%
Table 5.1.1 the distribution of countries and number of accident cases
22. 22
According to the information that gained from literature reviews section, the most
widely used concrete trucks are 3-axles trucks. The figure below shows the
percentage of types of concrete truck with different axles configuration:
Figure 5.1.2 the axles configuration distribution graph
Figure 5.1.2 indicated that about 73% of the accident cases that have been studied
in this project were 3-axles concrete trucks. This implied the database volume was
critical for the statistic analysis.
5.2 The Analyzing Factors
These were 15 possible contributing factors for the concrete trucks accidents have
been analyzed in this project. Those factors in the database were determined from
literature reviews and the suggestion made from a pavement company manager in
China in an interview.
27
8
2
3-axles
4-axles
2-axles
23. 23
As indicated in the literature reviews part, the weight difference between a fully
loaded and an empty concrete truck can be as large as 35 tons. The loading
condition was first determined to be a possible contributing factors in the database.
Whether the concrete trucks were loaded or empty when the accidents happened
was analyzed.
Secondly, the road condition can be another contributing factors for the concrete
trucks accidents. In order to determine this factors, the accidents locations for the
passed accidents were analyzed. There are three locations haven been analyzed in
the database, which are city road, highway, and construction area, as the road
condition can be significantly different in these area.
The visibility of the truck drivers can be a significant factor for the concrete truck
accidents. By investigating of the literature and accident repots. Several factors have
been introduced into the database which including, periods of the day, weather
condition, and environmental visibility. These factors were analyzed as an
indication factors for the visibility and analyzed separately to determine how were
them contributed to the concrete trucks accidents. Meanwhile, the blind points of
concrete trucks have been set as an independent possible contributing factor for the
concrete trucks accidents. Because of the blind point is differing from the visibility
and can be modified and improved easily.
24. 24
Besides the factors that have been discussed above, there were some other factors
determined as possible contributing factors and analyzed in this project as below:
Mechanic Failure
Accident Types
Drivers’ Errors
Damage, Injuries, and Fatality
Countries
Truck Types
Low Speed & Backing Up
6.0 Data Analysis & Discussions
In this section, the analysis of the project will be illustrated. As indicated in the
former sections, two types of analysis have been done for this project – Theoretical
Analysis, and Database analysis. However, the project was mainly based on the
statistic analysis (database analysis), the theoretical calculation was used to support
the database analysis or analyze the factors cannot get a good result from database
as lack of information.
25. 25
6.1 Theoretical Analysis
The theoretical calculations were analyzed two scenarios. Firstly, the forces acting
on a fully loaded concrete truck go through a curve. The second scenario is for an
empty concrete truck on the curve.
According to figure 4.2.2, 75% of the weights of the concrete truck were loaded on
rear axles. So for the theoretical calculation the front end of the concrete truck can
be neglected.
For the fully loaded condition:
The rear part of the concrete truck weighs about 10,000kg and has a height about
3.7 meters. The height without the mixer is about 1.6 meters.
The width between wheels of concrete truck = 1.4 m; height of wheel = 0.8m
The capacity of the concrete truck was 10 m^3 (indicated in the section 3.2)
The fully loaded concrete mass = 10m3 x density of concrete
The density of concrete = 2,400kg/m3
The mass of concrete = 10m3 x 2,400kg/m3 =24,000kg/m3
26. 26
To calculated the theoretical height of the center of gravity for the fully loaded
concrete truck by using the equitation as followed:
𝑥 =
𝑚1 ∗ 𝑥1 + 𝑚2 ∗ 𝑥2
𝑚1 + 𝑚2
x =
24,000kg∗
3.7m
2
+10,000kg∗1.6m/2
24,000kg+10,000kg
= 1.54m
The height of the center of gravity for a fully loaded concrete truck is about 1.54m.
The graph 6.2.1 indicated the force acting on the concrete truck when it is curving.
In order to keep the concrete truck not turn over, the Moment on for the concrete
truck should be 0 or the Moment that let the concrete truck roll over less than the
Moment to keep it in right orientation.
Graph 6.1.1 forces acting on truck
The forces acting the concrete truck when the concrete truck is curving as shown in
the graph 6.1.1.
27. 27
Where G is the gravity of the concrete truck = mass of concrete truck x 9.81N/kg
y is the offset of the center of gravity when speed (v) = 85 km/h; y = 0.15m
𝐺1 =
√(𝑥−ℎ𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑤ℎ𝑒𝑒𝑙)2
−𝑦2
𝑥−ℎ𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑤ℎ𝑒𝑒𝑙
𝐺
𝐺2 =
𝑦
𝑥−ℎ𝑒𝑖𝑔ℎ 𝑜𝑓 𝑤ℎ𝑒𝑒𝑙
𝐺
For the fully loaded condition
G1 =
√(1.54−0.8)2
−0.152
1.54−0.8
333𝑘𝑁 = 236kN
G2 = (0.15m/(1.54 – 0.8) m)*333kN =67.5 kN
The Moment of G1 is the resistance moment for the roll over
𝑀( 𝐺1) = 𝐺1 × (
𝑊𝑖𝑑𝑡ℎ
2
- y)
Moment of G2 is the moment let the concrete truck roll over
𝑀( 𝐺2) = 𝐺2 × 𝑥
M(G1) = 236𝑘𝑁 × (
1.4𝑚
2
– 0.15) = 129.8kNm
M(G2) = 67.5kN x 1.54m = 104.0kNm
M(G1)-M(G2) = 129.8kNm – 104.0kNm = 25.8kNm
When the speed decrease to 50km/hr; y = 0.06m
28. 28
Parameters Value
G1 331kN
G2 27kN
M(G1) 212kNm
M(G2) 41.6kNm
M(G1)-M(G2) 170.4kNm (>> 25.8kNm)
Table 6.1.1 fully loaded concrete truck @ 50km/hr
For the empty condition:
When the concrete truck is empty the center of gravity is about 1.2m.
The total weight of the concrete truck is about 10,000kg.
When the concrete truck traveling at 85km/hr, the center of gravity offset = 0.04m
G = 10,000kg * 9.81N/kg = 98.1kN
By applying similar calculation as the fully loaded condition:
Parameters Value
G1 97.6kN
G2 10 kN
29. 29
M(G1) 64.3kNm
M(G2) 12 kNm
M(G1)-M(G2) 52.3kNm (>> 25.8kNm)
Table 6.1.2 Empty concrete truck at 85km/hr
The results from the theoretical calculation showed that theoretically the high speed
and larger loaded do not turn the concrete truck over. However, by increasing the
speed or the loads of the concrete truck. It is likely to have a higher chance to tip
over.
6.2 Database Analysis
The database analysis was the main method for this project to analyze weather the
factors were the contributing factors of the concrete truck accidents. The analysis
was started with the entire database; all the data were analyzed as a whole to
determine the contributing factors in the whole database scale. Then, the separated
analysis for the North America cases and other countries were done for some of the
factors to give an indication for improvement of currently concrete truck high
accident rate and high damages.
30. 30
For some factors in other countries as the information was highly limited, the
separated analysis was not included in the databases analysis.
6.2.1 Damage & Injuries
The damages, injuries and the fatality are often highly considered as it indicates how
serious the accidents were. For the concrete truck, as it has some feature such as
large weight, and easy to roll over, the accident involved concrete trucks likely to
cause more damage and injuries.
In this section, the results of the analysis of the concrete truck with regard to
damage and injuries will be illustrated. And in this analysis, the properties damages
do not include the concrete truck itself in the accident. The properties damages refer
to the damages other than the concrete trucks in the accidents.
In the whole database scale, 32 out of 211 accidents that indicated the concrete
trucks caused properties damages. And the number for injuries and fatalities were
104 and 114, respectively. The figure 6.2.1 shows information of damages, injuries,
and fatalities.
31. 31
Figure 6.2.1 properties damage, Injuries and fatalities
The graph indicated that considerable number of accidents in the database cause
either injuries or fatalities. Actually, only 13 out 211 cases causes neither injuries
nor fatalities, that indicated that about 94% of the accidents in the database were
involved with human injuries or fatalities.
To consider that the data were collected from the accident report, some accident
may not reported as no people hurts or large damages to the properties. However,
the number was still big enough for serious consideration.
For separated data analysis as shown in the figure 6.2.2, the number of cases cannot
be used as a comparing factors as the volume of the accident cases collected for the
countries were significantly smaller than that in North America. However, form the
percentage it is easy to find, in the countries outside of North America the
properties damages were significantly higher. And the percentage of the injuries and
32
104
114
15.17%
49.29%
54.03%
0.00%
10.00%
20.00%
30.00%
40.00%
50.00%
60.00%
0
20
40
60
80
100
120
Properies
damage
Injuries Fatality
No. of cases
Percentage
32. 32
fatalities, the North America countries had a high rate for fatalities and lower rate
for the injuries.
Figure 6.2.2 Comparison figure (damage, injuries, and fatalities)
Even the percentage for each factor has some difference between North America
and other countries, but in both area the concrete trucks caused significant high rate
of damages and hurt human seriously in the accidents.
6.2.2 Loading Conditions
The theoretical calculation indicated that the loaded concrete trucks were easier to
have a accident. In this section, the database analysis is going to find if the loads can
contribute to the concrete truck accidents in the statistic method.
For the overall database analysis, 106 out of 211 accident reports provided
information about the loading conditions when the accidents happened. The table
below shows the information from the database:
0.00%
10.00%
20.00%
30.00%
40.00%
50.00%
60.00%
70.00%
80.00%
0
20
40
60
80
100
120
No. of cases
Percentage
33. 33
Loading Conditions No. Of Cases Percentages
Loaded 71 66.98%
Empty 35 33.02%
Table 6.2.1 loading condition distribution (entire database)
From the table 6.2.1, in the whole database scale, the percentage of concrete trucks,
which were loaded when the accidents happened, were twice as large as that for the
empty concrete trucks.
For the separated analysis, in North America scale the situation was similar for the
whole database analysis. 96 out 178 cases provided the information of the loading
conditions during the concrete trucks accidents. The table below shows the
information about it:
Loading Conditions No. Of Cases Percentages
Loaded 61 63.54%
Empty 35 36.46%
Table 6.2.2 Loading Condition Distribution (North America)
For other countries, as the volume limitation, all the 33 cases that collected for the
analysis indicated the concrete trucks were loaded when the accidents happened.
However, for the overall view of the database analysis, the loading condition was
likely to be a contributing factor for the concrete truck accidents.
34. 34
6.2.3 Accident Locations
The accident location was an important factorfor the concrete truckaccidents. Because of
the location in where the accidents happened can indicate different speed and road
conditions. 171 out 211 accidentcases in the database provided information of accident
locations. For over all database the distribution of accident locations were illustrated in
table below:
Locations No. Of Cases Percentages
Construction areas 74 43.27%
Highway 39 22.81%
City Road 58 33.92%
Table 6.2.3 accident locations distribution
From the database, 43.27% of the accidents happened in the construction zone, whichwas
happen than either city roads or highway.
For the separated analysis, the accident location distribution forNorth America was as
indicated in figure 6.2.3. Similar to the entire database, most of the accidents happened in
construction area.
35. 35
Figure 6.2.3 Accident location distribution (North America)
For other countries, as the limitation of cases, no accidents happened in construction area
were recorded in database. 25 out 33 cases were indicated happened in city,and 8
happened on highway.
In construction zone, the road condition was bad. More of the areas were unpaved. That
indicated that the road conditions have a significant influence in concrete trucks.
Meanwhile, in city the high volume and high density of traffic may lead to more accident
then that on highway.
6.2.4 Speed Factors
In the theoretical calculation, the high speed was not likely to cause the concrete
truck to roll over, however, the chance for the roll over of a concrete truck was
higher for the high speeds.
57.36%25.58%
17.05%
Con.
City
Highway
36. 36
For the entire database, 114 out 211 cases provided information of weather the
concrete trucks were over-speeding when the accidents happened. The table 6.2.3
shows the information with regard to this factor.
Speeding Factors No. Of Cases Percentages
Not Over-Speeding 90 85.54%
Over-Speeding 14 13.46%
Table 6.2.4 Speeding factors (entire database)
At this point, the speed not seems to be a contributing factor for the concrete truck
accidents. Then, the separated analysis have been done the results were as follow.
Figure 6.2.5a North America (speeding facotr) Figure 6.2.5b Other countires (speed factors)
The numbers of the accidents were not introduced to the analysis as the cases volumes for
other countires were smaller than the North America cases volmes. By comparing the
percentage information, the results showed as indicated in Figure 6.2.4a and 6.2.4b. In other
8.25%
91.75%
North America
Over
Speeding
Not Over
Speeding
85.71%
14.29%
Other Countries
Over
Speeding
Not Over
Speeding
37. 37
developing countires, a larger percentages of accidents were happened when the concrete
trucks went faster than the speed limits.
As the theoritcal calculation indicated the over-speeding is a contributing factorand the
significantly percentage of the accidents happened in other developing countires. The
speeding was determined as a contributing factor.However,for the cases in North America
the result from the database analysis shows only 18% of the accident happened when the
concretetrcuks were over-speeding. That indicated that, there some other factors
contirbuted more forthe concretetrucks accidents in the North America range.
6.2.5 Visibility Factors & Accident Periods
The accident periods was an indicating factors for the visibility factors, so this two
factors were analyzed together. As indicated in former sections, the visibility in this
analysis referred to the environmental visibility, which was caused by bad weather
or lighting conditions.
First of all, for the accident periods, 109 out of 211 accident cases in the database
provided information about the periods on the day that accident happened. The
distribution of this factor shows in the figure 6.2.6.
38. 38
Figure 6.2.6 the distribution of accident periods.
As indicated in the figure 6.2.5 only a small portion of the accidents happen at night
that because most of the construction work are doing in daytimes. For the morning
and afternoon cases, about 50% of the accidents happened in morning and 44% for
the afternoon. Even there was a 5% difference between these two periods, however,
the accident period was still determined not as a contributing factors for the
concrete trucks accidents.
For the separated analysis for the North America and other countries the results of
accident periods were similar to the entire database analysis. The results are as
indicated in the table 6.2.5 as follow
50.46%
44.04%
5.50%
Morning
Afternoon
Night
39. 39
No. Of Cases Percentages
North America
Morning 43 56.25%
Afternoon 33 41.25%
Night 2 2.50%
Other Countries
Morning 10 34.48%
Afternoon 15 51.72%
Night 4 13.79%
Table 6.2.5 the distribution for the accident period (North America & other
countries)
The visibility seems not to be a contributing factor for the concrete truck accidents
the analyzed results were shown in the table 6.2.5.
Ranges Visibility No. Of Cases Percentages
Entire database Good Visibility 34 82.93%
Bad Visibility 7 17.07%
North America Good Visibility 17 80.95%
Bad Visibility 4 19.05%
Other countries Good Visibility 17 85.00%
Bad Visibility 3 15.00%
Table 6.2.6 the Visibility in accidents
40. 40
For all the three categories of the database, more than 80% of the accidents
happened when the environmental visibility was good. That indicated that the
visibility was not a contributing factor for the concrete truck accidents.
6.2.6 Weather Conditions
The information for the weather condition in the database was limited, only 40 out
211 cases have indication of the weather conditions when the accidents happened.
Meanwhile, the weather condition was not suitable for comparison between North
America and other countries. For some location of the world, for example, Africa and
Southern area in China, the snow barely happens during the whole year.
From the entire database, the data showed 35 out of the 40 cases happened on a
sunny day and 3 cases happened during a rain and only 2 accidents happened on an
icy day.
The concrete pavement or construction works were not usually made in the cold
condition as the concrete harden slowly at low temperature, that why only 2
accidents on a snowy day were collected. Besides, as 35 out 40 cases happened on a
sunny day indicated that the weather condition was not a contributing factor for the
concrete trucks in North America.
41. 41
6.2.7 Accident Types
For the entire database, 141 out of 211 accident cases provided information regard
to the accident types. The roll over accidents occupied over 40% of the 141 cases.
The detail distribution was shown in figure 6.2.7.
Figure 6.2.7 distribution of accident types
For the separated analysis for North America and other countries, in both
categories, the roll over accident took largest percentage of the total knowing cases.
The figure below illustrated the distribution of accident types in North America and
other countries.
10
27
47
57
7.09%
19.15%
33.33%
40.43%
0.00%
5.00%
10.00%
15.00%
20.00%
25.00%
30.00%
35.00%
40.00%
45.00%
0
10
20
30
40
50
60
No. Of Cases
Percentage
42. 42
Figure 6.2.8a Accidenttype (North America) Figure 6.2.8b Accidenttypes (other countries)
From the graphs above it easy to find that the roll over was the most common type
for the concrete truck accidents. Besides, in other countries category more
read-ending accidents happened than that in North America. That may lead by more
over-speeding cases or more mechanic failure that will be discussed in section 6.2.8.
6.2.8 Drivers’ Errors
With regard to the entire database, 66 out of 211 accident cases were confirmed
caused by miss-operations of the concrete trucks drivers. That took 31.28% of the
total accident cases that collected in the database.
For the separated analysis, in North America range, 59 out of 178 accidents were
caused by the drivers’ miss operating that is about 33% of the total accidents, which
were collected in the database. For other countries, nearly 22% (7 out of 33) of the
accidents were caused by the drivers’ error. It was believe that the low case volume
lead to the other countries had a low rate in human error. And on the other hand, in
both North America and other countries cases, some accidents did not indicate the
3.81%
20.00%
37.14%
39.05%
Rear-ending
Head-on
Collision
Over run
Roll Over
16.67%
16.67%
22.22%
44.44%
Rear-ending
Head-on
Collision
Over run
Roll Over
43. 43
caused had a high probability caused by human error. The mean the rate for human
error could be even higher than that be calculated from the database analysis. For
the overall views of the database, the human error was likely to be a contributing
factor for the concrete truck accidents.
6.2.9 Mechanic Failures
For the mechanic failures, the database also lack of information about the mechanic
failure. Only 26 out of 211 accident reports provided information of mechanic
failure when the accident happened. From the available information, the most
common mechanic failure was the brake problems, which took 34.62% of total
knowing cases. And 11.54% were caused by tire broken.
For the comparison of North America cases and other countries cases, the
percentage of mechanic failure caused 21.2% of the accident in other countries,
which was higher than 10.6% in North America.
That indicated the maintenance works in North America were better than that in
other countries from the database analysis. Meanwhile, it indicated that the
mechanic failure was not a major contributing factor to the concrete trucks
accidents.
44. 44
6.2.10 Slow Moving (Blind Points & Backing Up)
In the database, 58 out 211 accident cases indicated that the accidents happened
when the concrete truck moving very slowly. And 30 out of these 58 cases were
happened when the concrete trucks were backing up. That indicated that, the
concrete trucks were easy to involve in the accidents while it backed up.
For the blind points of the concrete truck, the blind points caused 33 out of 211
accidents in the database. By combining the blind points with the backing up factor,
it turned out to show that 60% of the backing up accident also involved with the
factors of blind points.
The results of this analysis indicated that the blind point was a contributing factor
for the concrete truck accidents. Especially when the concrete trucks were backing
up.
45. 45
7.0 Conclusion
The project were analysis the factors that involved in concrete trucks accidents in
both statistic and theoretical methods. Over 300 accident cases were reviewed and
211 accident cases were analyzed on the project database.
Some limitations of this project were found during the data analysis processes. The
lack information in the accidents report limited the statistic analysis. Some factors,
for example, mechanic failures, visibility, and weather conditions, cannot be well
analyzed because of most of the accident reports did not provide information
regarding to these factors.
Nevertheless, the project was still able to determine some of the contributing factors
for the concrete truck accidents. The results from both theoretical analysis and
database analysis indicated that, the over-speeding and fully loaded concrete trucks
were more likely involving in an accident. The means the speed and loading
condition are the contributing factors for the concrete trucks accidents. Besides, the
blind point is another contributing factors for the accidents, especially when the
concrete trucks are backing up.
The accident locations analysis indicated the great influence of road conditions for
the concrete trucks accidents. General speaking, the speed of concrete truck was
relatively lower in construction zone than city roadway or highway. But more
46. 46
accidents were happened in construction zones, which indicated bad road condition
was contributing to the concrete trucks accidents.
With regard to drivers’ error, miss operating of the truck drivers is one of the
contributing factors in concrete truck accidents. In North America there still more
than 1/3 of the accident was caused by the human error as indicated in the
database.
47. 47
8.0 Reference
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www.aggregateresearch.com
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Inquirer news n.d., MMDA issues new rule to prevent car crashes with cement
mixers, Retrieved from
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Rue, Ziffra n.d., Cement Tuck, Construction Truck Accidents Retrieved from
http://rueziffra.com/construction-truck-accidents on 17th Mar. 2014.
Rue, Ziffra n.d., What are the Common Causes of Cement Truck Accidents? Retrieve
from
http://rueziffra.com/causes-of-cement-truck-accidents-daytona-beach-attorney on
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Voice of Stamford n.d., Concrete Truck Dimensions, Retrieved from
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2013
北京交通大学,负载卡车的中心偏移量分析, Retrieved from
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