The Impact of Highway Design and Construction Practice Defects on the Safety of Nigeria Roads
CHAPTER ONE
OBJECTIVES OF STUDY
(i). To investigate how highway design and construction practice have impacted the safety of Nigerian road users
(ii). To identify and investigate the contribution of road conditions to highway safety
(iii). To open public debate / discussion on the contributing effects of highway sections and geometry to the safety of Nigeria roads
(iv). To identify and investigate the rates of crashes at selected black spots in Nigeria and develop a taxonomy (classification of such “accident – prone” black spots. )
(v) To develop a framework for the computation of road safety Index in Nigeria for design and construction management purposes
(vi) Implant a prototype scoring- based decision support system for road safety Analysis in Nigeria
CHAPTER TWO
LITERATURE REVIEW
BACKGROUND
Death on our roads has been a heart troubling issue since the advent of automobile. This has brought about several discussions on how to make Nigerian roads safer. In doing that, the road design and the method employed in its construction, are important variables in making the road safer. Safe road design is now about providing a road environment which ensures that vehicle speeds will be within the human tolerances for serious injury and death to be avoided.
As a matter of fact, in carrying out this research, the literatures on highway design and construction practice in relation with safety were reviewed.
A 1985 US study showed that about 34% of serious crashes had contributing factors related to the roadway or its environment [29]. Most of the crashes also occur at locations that do not look dangerous. This is, in part, because if drivers perceive a location as hazardous, they take more care. Accidents may be more likely to happen when hazardous road or traffic conditions are not obvious at a glance, or where the conditions are too complicated for the limited human machine to perceive and react in the time and distance available.
Careful design and maintenance, with well-designed intersections, road surfaces, visibility and traffic control devices, can result in significant improvements in accident rates.
In this research work, therefore, issues like the geometric design of roads, road furniture and the likes are investigated and discussed.
GEOMETRIC DESIGN
The geometric design of a highway, deals with the dimensions and layout of visible features of the highway such as alignment, sight distance and intersection. In other words geometric design includes coordinated road alignments, adequate cross sections, sight distances and features that allow the safe operation of the traffic at the required speed [24]. The geometrics of highway should be designed to provide optimum efficiency in traffic operation with maximum safety at reasonable cost. The designer may be exposed to either planning of new highway network or improvement of existing highways to meet the requirements of the existing and the anticipated traffic. It is possible to design and construct the pavement of a road in stages; but it is very expensive and rather difficult to improve the geometric elements of a road in stages at a later date. Therefore, it is important to plan and design the geometric features of the road during the initial alignment, taking into consideration the future growth of traffic flow and possibility of the road being upgraded to a higher category or to a higher design speed standard at a later stage.
Roads that blend well with the environment are usually visually attractive and physically unobstructive [24]. The general rule is for designers to follow the natural contours of the land, using graceful and gradual horizontal and vertical transitions, and aligning the road to natural features such as mountains and rivers.
GEOMETRIC DESIGN ELEMENTS
According to Gupta and Gupta [26], geometric design of highway deals with the following elements:
- Cross section elements – pavement width, formation width etc
- Site distance
- Horizontal and vertical alignment details
- Intersection elements
ROAD-WAY CROSS SECTION
Road way cross section shown in Plate 2.1(a – d) is the view obtained in a section cut between the right of way lines perpendicular to the direction of travel along the road. It includes features of the traveled portion of the road used by vehicular traffic as well as on the road side. In highway Engineering community, the design of a road cross section elements influences a roadway cost, operation and safety.
Road cross section elements are designed bearing in mind the expected usage of the facility. For example, a road way for higher design volumes and speed, require more lanes, flatter grades and more gentle curves than those of lower volume and lower design speed. In selecting the appropriate cross section elements and dimensions, designers need to consider a number of factors, including the following:
- Volume and composition (percent trucks, buses, and recreational vehicles) of the vehicular traffic expected to use the facility
- The likelihood that bicyclists and pedestrians will use the route
- Climatic conditions (e.g., the need to provide storage space for plowed snow)
- The presence of natural or human made obstructions adjacent to the roadway (e.g., rock cliffs, large trees, wetlands, buildings, power lines)
- Type and intensity of development along the section of the highway facility that is being designed
- Safety of the users
The most appropriate design for a highway improvement, is the one that balances the mobility needs of the people using the facility (motorists, pedestrians, or bicyclists) with the physical constraints of the corridor within which the facility is located. [13]. Fig 2.2. below shows a road in which pedestrian and bicycle traffic, is considered.
CHAPTER THREE
METHODOLOGY
This chapter discusses the methods used in carrying out the research work. Various methods which were found appropriate to this kind of research work were adopted. The methods are enumerated sequentially below.
DATA COLLECTION AND SOURCES OF DATA
Sources of data in a general sense are of two types; the primary sources and the secondary source. Both of these sources were adopted in this work.
Primary sources
The primary sources of data are the materials or information collected at first hand (by the user or paid agent) especially from original sources and for the user’s intention. Such data are usually gotten through interviews, questionnaires, surveys, planned experimental observation or recording of official transactions, among others.
But for this particular work, a few of the above listed sources were adopted. One of them is the questionnaire. A questionnaire may be said to be a written interview prepared, which is presented to a respondent. For this particular work structured questionnaire were used. The questionnaires were grafted after much consultation from both published books and the internet.
CHAPTER FOUR
PRESENTATION AND ANALYSIS OF DATA
PRESENTATION OF DATA
The data gathered are presented in this chapter. The first set of data is the Road Traffic Crash Data gotten from Federal Road Safety Corps (FRSC) Nigeria. The second set of data presented is obtained from the responses contain the questionnaires and interviews obtained from the field.
CHAPTER FIVE
DISCUSSION, CONCLUSION AND RECOMMENDATION
DISCUSSION OF FINDINGS
The findings made during the course of this research work are discussed in this chapter. It is worthy to note that at this point that citing the limited literature concerning this topic and several searches by different search engines in the World Wide Web indicates that there is no previous work dedicated totally to this topic. Therefore the findings obtained are from the questionnaire, the interview, site visits and the Federal Road Safety Corps (FRSC) Road Traffic Crash (RTC) data for 2011 and 2012. The findings are related to the research questions.
RESEARCH QUESTION 1
What factors are responsible for accident on the roads?
There are various things that cause road accident. These causes according to FRSC (2008) are three. These include;
- Human Factor
- Mechanical Factor
- Environmental Factor
Human Factor
The human factor has to do with the driver, passenger and pedestrian. Looking at the driver factor, we have things like overconfidence, speeding, loss of concentration, tiredness, driving under the influence of alcohol. Others include driving under the influence of drugs, indiscriminate parking and dangerous overtaking.
Some crashes occur on roads that are straight and smooth. This is not the fault of the road; rather the fault of the driver. Some drivers while on the steering starts speeding given that the road is smooth and thereby stop concentrating on driving. Before you could know it, they have already crashed.
On the part of passengers – the contributing factors are distraction of the driver and non chalant attitude. On this non challant attitude, “passengers board buses, taxis and private vehicles without even taking a look at the tyres to see if they are worn out. They often encourage speeding, reckless driving, overtaking at bends and other dangerous practices by either cheering on the driver or keeping quite”. [5]
The pedestrian on their own part, contribute to human factor by not observing road traffic rules and regulations. Some pedestrian walk or run across the road without looking and ensuring the road is safe to do so, while others do not wear reflective dresses or clothes at night so that drivers could easily see them.
Mechanical Factor
Crashes due to mechanical factor have to do with malfunctioning of the vehicle, which eventually leads to loss of control of the vehicle and invariably to road traffic crashes. These factors include the following:
- Malfunction of engine
- Poor steering mechanism
- Defective horn
- Defective lighting system
- Tyre burst
- Brake failure
- Failed wipers during raining season etc
Environmental Factor
This includes the following:
- Pot holes on our roads
- Improperly placed or absence of road signs
- Bad roads
- Absence of road markings
- Collapsed bridges
- Slippery surfaces etc
It is worthy to note that, this research work focused on the environmental factors. As a matter of fact, looking at the responses of the respondents to the questionnaires distributed, in relation to the research question “I”, ten (10) respondents representing 37% of the population agreed while 16 respondents which represent 59.3% of the population strongly agreed. The combination of those that agreed and those that strongly agree gave a total of 26 respondents which represent 96.3% severity Index.
On other hand only one respondent representing 3.7 percent of the population disagreed.
This data above substantiates the fact that other factors also contribute to road traffic crashes.
RESEARCH QUESTION 2
Is there any relationship between accident occurrence on roads and nature of the road specifically design and construction Engineering related factors?
First of all from the people interviewed, there is a very big relationship between the accident occurrence on our roads and the nature of the road. From the questionnaire that was distributed, question 5 helped in answering the above research question. 10 respondents representing 39% of the population agreed while 15 respondent representing 57% strongly agreed. The combination of those that agreed and those that choose strongly agree, represent 97% of the population in favour of the fact that bad road contribute to a great extent, the number of road crashes that occur on our roads. If bad road contribute to accident occurrence what it means is that they are related. 97% of the population agreeing to this fact is very significant. Only 3% disagreed. This suggests that accident occurrence is related to bad road.
The above finding can also be substantiated from the RTC data of FRSC. From the RTC data, some roads have higher level of accident/crash occurrence as can be pictured from figure 4.1. The road which has the highest number of crashes is the Enugu – Porthacourt Expressway. It is one of the worst roads that were complained about by drivers interviewed. It is worthy to note that this number of accident is only the once rescued by FRSC. What that means is that there are other accidents that happened on this route which was not recorded simply because they are not grave or there is no loss of life recorded or FRSC could not be reached when it occurred. These once rescued in other words leads to loss of lives and properties and probably caused heavy traffic jam that’s why FRSC was contacted.
RESEARCH QUESTION 3
Do you think that majority of accident on the roads as a result of bad roads?
A good number of people believed that majority of accident on the road are as a result of bad road. This can be substantiated from the responses. From the analysis of question 13 as was carried out in chapter four, 22 respondents representing 84.6% of the population selected YES while 4 respondent representing 15.4% choose NO.
Thus 84.6% of the sample believe that majority of accident on our roads is as a result of bad. Only 15.4% of the population opposed to this fact.
RESEARCH QUESTION 4
Do design practice and or construction methods affect or contribute to the non-structured nature of Nigerian roads, resulting in high frequency of accident and increased vulnerability of road users?
Those approached during the course of this research work agreed to the fact that bad road in Nigeria are as a result of the way the roads are being constructed. Some argue that incompetent contractors contribute a lot to this fact. As a matter of fact “constructions or repairs of major roads in the country should be given to competent and credible contractors to maintain on yearly basis, to avoid dilapidation” [28]
The responses gathered added supports above assertion. From the questionnaire, 6 respondents representing 22.2% of the population agreed that Bad roads found in Nigeria are as a result of poor quality of work done on the road during Construction. 18 respondents which represent 66.7% of the sample strongly agreed to this fact. The combination of those that agreed and those that strongly agree give a total of 24 respondents which represent 88.9% of the population. This makes it clear that construction method contribute to the bad nature of roads in Nigeria.
CONCLUSION
The methods of highway design and construction in Nigeria, have really impacted on the safety of lives on our roads. The roads have been of good help as it has enhanced easy movement of goods and persons. But, the bad aspect of it is the continual loss of life on these roads. This has been attributed to the poor highway and construction practice. The methods in which road construction in Nigeria are carried out by some contractors, need urgent change for improvement. From the responses, some believed that contractors cut corners to make profit, thereby sacrificing the quality of work done on the roads which leads to the increase in the loss of lives and properties. Also, lack of proper maintenance, has contributed a lot in the loss of lives on our roads.
This increase in loss of lives on our roads, has made many to describe our roads as a “DEATH TRAP”. People travelling on road always carry their heart in their hands praying to God until the journey ends. It is good to pray, but most prayers while on motion, are mere wishes stated aloud given that commuters are afraid of losing their life, because many have gone while using the road.
Finally the loss of lives on our road can be ameliorated if good road design and construction methods, are employed and properly implemented by contractors.
RECOMMENDATIONS
Based in the findings in this work, the following recommendations are given:
- The government should always award contracts to competent credible and reliable designers and contractor.
- The government should ensure strict supervision of road projects awarded during construction.
- Government should also ensure proper and on time maintenance of roads in Nigeria once they are completed and put to use.
- FRSC should include the nature of crash location in their RTC report format
- Road design and construction should be done according to world standard because the road users here in Nigeria are human beings like their folks in the developed world
- Drivers using Nigeria roads should apply caution in using the road since these roads are poorly designed and/or constructed.
- Government should endeavor to commission roads projects only when all safety measures must have been put in place.
- Government should harken to the cry of the United Nation (UN) on Decadefor Action on Road Safety.
REFERENCES
- Abdul Awa,l A. S. M. and Warid-Hussin, M. (2011). Effect of palm oil fuel ash in controlling heat of hydration of concrete. Procedia Engineering, vol. 14, pp. 2650–2657.
- Adaba, C.S; Agunwanba, J.C; Nwoji, C.U; Onya, O.E and Ozeh, S; (2012). Comparative cost and strength analysis of cement and aggregate replacement materials. Nigerian Journal of Technology – Vol 31, Pp 111-115
- Adesanya, D. A. and Raheem A. A (2009). A study of the workability and compressive strength of corn cob ash blended cement concrete, Construction and Building Materials Vol.23 (1) Pages 311 – 317
- Adeyemi, A. (2013). Compressive Strength properties of concrete and mortar containing ashes and partial replacement for cement. (Unpublished MSc Dissertation) ABU Zaria
- Afolayan, J. O (2013). Suitability of Coconut Aggregate as Coarse Aggregate in Lightweight Concrete. A Dissertation presented to the department of Civil Engineering ABU, Zaria
- Agbede, I.O. and Manaseh, J.(2009) Suitability of Periwinkle Shell as Partial Replacement for River Gravel in Concrete. Leonardo Electronic Journal of Practices and Technologies pp.59-66.
