The Impact of Extreme Rainfall on Road Transport Accident in Port Harcourt
Chapter One
Aim and Objectives
This study aims to analyze the effect of extreme rainfall on the occurrence of RTAsin Port Harcourt, Rivers State. In order to achieve the aim of this study, the specific objectives are to:
- examine the monthly and annual trends of rainfall (number of wet days inclusive), temperature, visibility, relative humidity, wind speed and evaporation rate in the Port Harcourt from 1979 to 2014;
- analyze the spatial variation of RTAs along six major routes in Port Harcourt;
- analyze the temporal variation of RTAs in Port Harcourt from 2001 to 2014;
- assess the nature of the association between rainfall, temperature, visibility, relative humidity, wind speed and evaporation rate and RTAs in the study area;
CHAPTER TWO
THEORETICAL FRAMEWORK AND LITERATURE REVIEW
Theoretical Frame work
System Theory of Accidents
Road accidents are seen as failures of the whole traffic system. It arises from interactions among humans, machines and the environment. It is not simply chains of events or linear causality, but more complex types of causal connections because under normal circumstances, chances of an accident are low. Road transport accidents are seen as failures of the whole traffic system (interaction between the three elements) rather than a failure of the driver only. Under normal circumstances, chances of an accident are low. Rather than looking at the environment as being full of hazards and people prone to errors, system safety assumes that harmony (steady state) exists between individuals and the work environment. Thus, the driver is a victim as this assumes that the demands that the traffic system put on the driver is too complex for the driver‘s limited capacity to process information.
As a result of this assumption, the system must be designed to be less complex, which preventserrors from occurring. The system must also reducethe negative consequences of errors; introduce safety margins that allow the driver to incur an error without being hurt too seriously. This theory therefore enhances our understanding of the three major contributory factors of road accident including human, mechanical and environment. Thus, system theory is based on man- environment adjustment and maladjustments (Muhlrad and Lassarre, 2005) and the components of the theory are the environment, means of transportation (vehicles) and the behavior of man (Krug, Sharma and Lozano, 2000) enhancing our understanding of the major contributory factors leading to road transport accidents.
Jorgensen and Abane Model for Traffic Accidents
A model for traffic accident as inspired by the ecological model of a disease was developed by Jorgensen and Abane (1999) to suit road transport accident analysis. This model is characterized by three main components:
- The vehicle (corresponding to the vector in disease ecology) which describes vehicles into its composition, age, technical conditions and safety equipment like seat belts in a car
- The environment consisting of the road system and the wider physical and built up The physical environment splits further into different aspects such as daylight and climate (weather conditions and road conditions), spatial conditions, settlement pattern, situation of areas of residence and work areas, principle of traffic separation, topology and road construction qualities.
- The behavior of the population including its characteristics such as sex ratio as well as attitude and general traffic
- The Single Event Theory
This theory is based on the ‗assumption that an accident consists of a single event that has a cause. Find the cause, and you have explained the phenomenon. The investigative task is easy: find the cause and correct it and you will prevent accidents. This perception seems rooted in primitive history. If an unusual phenomenon occurred and there was no ready explanation for it, the survivors sought a scapegoat as the ―cause‖ of the occurrence. Find the cause and the victims are satisfied. History offers numerous examples, including acts of God precepts which carry over into present day insurance policies. Anyone who has observed the media‘s handling of an accident will recognize some evidence of this perception. While largely discredited by the scientific community, vestiges of this theory can be widely observed.
Accidents are still frequently defined as an ―event‖ in safety publications and military investigation manuals, for example(National Safety Council, 1976). Many aspects of our legal system in the highway safety field also provide evidence of this perception, such as police citations for accidents, and some of the arguments about ―no-fault‖ insurance legislation. Publication of accident cause statistics reinforces this view, and the use of these statis tics in the media perpetuates it. It is a world-wide perception, as evidenced by the World Health Organization‘s classification of the causes of death. The principal difficulty is that the view encourages an incomplete examination of the accident phenomenon.
CHAPTER THREE
RESEARCH METHODOLOGY
Reconnaissance Survey
In an attempt to prepare for the collection of data for this study, a reconnaissance survey of Port Harcourt Unit Command of the FRSC was carried out to identify the extent of this unit command. The major routes, FRSC office, Nigeria Meteorological Agency Office were visited and interaction with officers of both organizations undertaken. Thus, the major routes were identified and preparation was made for the collection of data required for the study.
Types of Data
In order to achieve the aim and objectives of this study, data on traffic flow, RTA and weather were obtained. Data on traffic flow include the following:
- Date
- Time
- Peak periods of motor vehicle movement
- Number of vehicles plying each route carried out by counting and recording manually
Accident record from Federal Road Safety Commission included the following:
- Date of accident
- Time of occurrence of accident
- Location/route of accident
- Number of road transport accident cases
- Type of accident (fatal, severe or minor)
- Number of people injured and or killed
- Probable causes
Data on the selected weather parameters was acquired from the Nigerian Meteorological Agency which includes:
- Daily rainfall
- Mean daily air temperature
- Mean daily visibility
- Mean daily relative humidity
- Mean daily wind speed
- Mean daily evaporation rate
Sources of Data
Primary Source
Daily peak periods were established based on the reconnaissance survey conducted. Traffic sensitive points were used which allowed for the counting of moving vehicles. This exercise was carried out for three weeks along each route in the study area.
CHAPTER FOUR
RESULTS AND DISCUSSION
Trends of the Major Weather Parameters within the Study Area
Trend in Rainfall
The trend in rainfall in the study area is presented on Figure 4.1 which presents the original trend, average and trend line representing rainfall experienced in the study area.
CHAPTER FIVE
SUMMARY, CONCLUSION AND RECOMMENDATION
Summary of Major Findings
In Port Harcourt, climate trend revealed that there is a general increase in the amount of rainfall, number of wet days, air temperature, visibility and relative humidity and a decrease in wind speed and evaporation rate. Furthermore, Port Harcourt-Rivers and Port Harcourt-Aba routes recorded more RTA cases and casualties than the others. Port Harcourt-Rivers route recorded 419 cases and 1722 casualties while Port Harcourt-Aba route recorded 408 cases and 1448 casualties. This study found out that dangerous driving, speed violation and loss of control are the leading causes of RTAs with dangerous driving being the number one cause of RTAs in Port Harcourt. Current trend analysis revealed that there is a general increase in the number of RTA cases and casualties in Port Harcourt.
In Port Harcourt Township, only dangerous driving was responsible for RTAs in all the months of the year. Along Port Harcourt-Rivers route however, it was dangerous driving, speed violation, loss of control, tyre burst and wrongful overtaking. Along Port Harcourt-Aba route, it was dangerous driving, speed violation, loss of control and tyre burst. No particular cause of RTAs was responsible for RTAs in all the months of the year along Port Harcourt-Sokoto, Old Port Harcourt-Aba and Port Harcourt-Yenegoa routes.
The highest number of fatal RTA cases was recorded in 2012, serious cases in 2013, minor cases in 2009, number of passengers injured in 2007 while the number of passengers that were killed per year was in 2013. The highest number of RTA cases recorded per year was in 2013 while casualties were in 2010 and 2012. Similarly, the highest number of fatal RTA cases was recorded in July, serious cases in September, minor cases in June, number of passengers injured in September while the number of passengers that were killed was in January. The highest number of RTA cases and casualties however were recorded in July and January.
The result of the correlation analysis between RTA parameters and weather parameters on annual basis revealed that rainfall, visibility and wind speed had a positive association with all the RTA parameters, number of wet days had a negative association with all of them except minor cases and the number of passengers killed during RTAs, a ir temperature positive association with all of them except minor cases, relative humidity has a negative association with all of them except total cases while evaporation rate had a negative association with all the RTA parameters except with minor cases.
In addtion to that, the result from monthly analysis between RTA parameters and weather parameters revealed that rainfall had a positive association with all the RTA parameters except the number of passengers either injured or killed, a ir temperature had a positive association with all of them except with serious cases, total number of cases and the number of passengers killed, visibility had a negative association all of them except with minor and total cases, relative humidity had a negative association with all of them except serious, minor and total cases, while wind speed and evaporation rate had a negative association with all the RTA parameters except with fatal cases, number of passengers killed and total casualty.
Annual analysis of the nature of association between probable causes of RTA and weather for the most significant probable causes of RTA revealed that the more the amount of rainfall, number of wet days, wind speed and evaporation rate on one hand and the more friendly the temperature is and the poorer the visibility becomes annually, the more the number of fatal cases of RTA as a result of speed violation. Loss of control was positively associated with rainfall, air temperature, visibility and wind speed and negatively associated with relative humidity and evaporation rate with respect to the frequency with which fatal, serious and minor cases were linked to it. Dangerous driving on the other hand was positively associated with rainfall, number of wet days and wind speed and negatively associated with air temperature, visibility, relative humidity and evaporation rate with respect to the frequency with which fatal cases were linked to it.
Monthly analysis was carried out and speed violation revealed a negative association with rainfall and relative humidity with respect to the frequency with which fatal cases were linked to it while it showed a negative association with all these climatic elements with respect to the frequency with which serious cases were linked to it. A positive association was discovered between loss of control, air temperature and evaporation rate on one hand and a negative association between it, wind speed and evaporation rate on the other with respect to the frequency with which fatal and serious cases were linked to it. A negative association was discovered between dangerous driving, wind speed and evaporat ion rate on one hand and a positive association between it, rainfall and relative humidity on the other with respect to the frequency with which fatal and serious cases were linked to it.
Furthermore, there is a general tendency in Port Harcourt that greater amount of rainfall will lead to more RTAs and lesser rain-crash-index. Secondly, the probability that a RTA will occur on any wet day is 0.24 while it is 0.28 on any dry day while the probability that a RTA will occur on a no dry spell wet day is 0.39, 0.55 on a small dry spell wet day and 0.06 on a large dry spell wet day. Port Harcourt also revealed a negative rain-crash-effect showing that more RTA cases occur per unit dry day than unit wet day.
The amount of rainfall recorded three, four or five days before any day have a significant positive relationship with the number of passengers killed, minor and fatal cases of RTA respectively that will occur on that day while the amount of rainfall recorded three days before any day has a significant negative association with the number of serious and total cases that occurred on that day. Finally, class two rainfall (>1 to 2mm) has the highest rain-class-crash-rate followed by class four rainfall (>5 to 15mm), class five (>15 to 30mm), class three (>2 to 5mm), class six (>30mm) and finally, (>0 to 1mm).
Conclusion
In Port Harcourt, climate trend revealed that there is a general increase in the amount of rainfall, number of wet days, air temperature, visibility and relative humidity and a decrease in wind speed and evaporation rate. Furthermore, Port Harcourt-Rivers and Port Harcourt-Aba routes recorded more RTA cases and casualties than the others.Port Harcourt-Rivers route recorded 419 cases and 1722 casualties while Port Harcourt-Aba route recorded 408 cases and 1448 casualties. The number of RTA cases and casualties are at an increase in Port Harcourt and the primary causes are dange rous driving, speed violation and loss of control respectively. The nature of association between these weather parameters and RTA parameters be it fatal, serious, minor or the totality of RTA cases on one hand or the number of passengers injured or killed or the totality of casualties from RTAs on the other vary from one weather element to another or from one month to another or one year to another.
Furthermore, there is a general tendency in Port Harcourt that greater amount of rainfall will lead to more RTAs and lesser rain-crash-index. Secondly, the probability that a RTA will occur on any wet day is 0.24 while it is 0.28 on any dry day while the probability that a RTA will occur on a no dry spell wet day is 0.39, 0.55 on a small dry spell wet day and 0.06 on a large dry spell wet day. Port Harcourt experienced more RTA cases per unit dry day than unit wet day. The amount of rainfall recorded three, four or five days before any day have a significant positive relationship with the number of passengers that will be killed, minor and fatal cases of RTAs respectively as a result of the occurrence of RTAs on that specified day.The amount of rainfall recorded three days before any day has a significant negative association with the number of serious and total cases that occurred on that day. Finally, class two rainfall (>1 to 2mm) has the highest rain-class-crash- rate followed by class four rainfall (>5 to 15mm), class five (>15 to 30mm), class three (>2 to 5mm), class six (>30mm) and finally, (>0 to 1mm).
Recommendation
There exist a certain degree of interaction between weather and RTAs which vary from one weather element to another and from one point in time to another. Thus, since this is one area that has received little attention even in the words of the Intergovernmental Panel on Climate Change, more attention should be given to this idea. Hence, this is a reality in this study area because not a single RTA case was linked to weather to the best of the researcher‘s knowledge. Thus, with the level of RTA cases and casualties in Nigeria, the academics, the FRSC, Nigerian Meteorological Agency, Federal Ministry of Transportation and all relevant stockholders like the National Union of Road Transport Workers and Centre for Disaster Risk Management and Development Studies, A.B.U, Port Harcourt should be brought together under the chairmanship of Professor E.O. Iguisi or Professor I.M. Jaro in order to exploit this idea hence, curb this disaster in Nigeria and the world as a whole.
The next step however is that Nigerian Meteorological Agency and FRSC must work under one umbrella in such a way that as soon as Nigerian Meteorological Agency present the regular weather forecast which should be presented not only on the television and radio but via all forms of social media available, the FRSC should be there to immediately explain to the nation the implications of the weather forecast on road users and the occurrence of RTAs. Thus, standard weather stations should be provided by the government and stakeholders along the most RTA prone highways in the country. Training and retraining of officials of these agencies is crucial and not forgetting that a close collaboration with academics and research institutes is inevitable. These will help us go a long way in solving this disaster.
In this order to actualize these recommendations, the present study has conducted an in-depth research on this subject matter so as to serve as a good guide for other researchers and agencies who wish to study this subject matter in the further. In order to achieve the aim of the present study, make the aforementioned point possible and the realization of the first recommendation, the research looked at the driver, vehicle and the environment in additio n to a careful examination of all the causes of RTAs as enlisted by FRSC, Nigeria. This is because of the relevance and urgent need to reduce the high rate of RTAs in Nigeria. Secondly, in order have a better understanding of the complex nature of association between weather and the occurrence of RTAs. Thirdly, in order to key into IPCC‘s recommendation for studies to be carried out globally in order to understand the consequences of climate change and changing weather conditions on transport sector.
Thus, this is a multi-disciplinary issue that deserves a multi-disciplinary approach. Hence, NIMET, FRSC, Nigerian Police Force (NPF), climate experts, transport experts, medical practitioners, engineers, physicist, mathematicians, statisticians, computer scie ntists, Standard Organization of Nigeria (SON), the automobile industry among a lot more should all key into this idea. The Nigerian Government, NIMET, FRSC and CDRMDS, ABU, Port Harcourt should champion this course and the Federal Government should be visibly seen to be sponsoring and encouraging researches like this while NIMET and FRSC should utilize the expertise of these of these experts and their findings for the achievement of the second recommendation. Hence, research in this area must be continuous due to the dynamic nature of extreme rainfall. Finally, the Federal Government should be responsible for enacting and enforcing laws resulting from these researches and expert opinions.
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