Road Safety Audit Evaluation of Typical Two Lane Divided Highway in Nigeria

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1 Vol. 1, No. 3, pp: 55-64, 2017 Published by Noble Academic Publisher URL: Open Access Road Safety Audit Evaluation of Typical Two Lane Divided Highway in Nigeria Nura Bala a*, Musa Adamu b a*,b Department of Civil Engineering, Bayero University Kano, Kano-Nigeria Abstract: As a consequence of the increasing number of traffic volume, road safety improvement is becoming a major policy issue for road authorities. Road accidents create both social and economic cost on the country s economy. In pursuance of road safety improvement, it is important to display different solution alternatives considering the budget limitations of the road authorities. In this research, road safety audit practices from different countries were reviewed and best practice options from these were applied for road safety audit in Nigeria. The overall roadway section evaluated had a score of 5.7 showing that the overall effectiveness of the road is below average and so much has to be done to improve the condition of the road. It is also recognized that the most common hazards observed are fixed massive objects within the safety zone area, deficient guardrails, pavement damages like potholes and edge deterioration, missing shoulders, improper pedestrian crossings, improper commercial and bus stop locations, activities which indicates that majority of the hazards observed are associated with road design. Fixed objects, roadway cross section elements, bus stops, intersection layouts, roadway signage and pavement conditions were assessed for their potential to induce risk and danger to drivers and pedestrians. The findings point to a need for incorporation of safety at the design stages and during construction and maintenances of roadway facilities. Keywords: Road Safety, Road Safety Audit, Road Traffic Accident, Road Fatalities, Vulnerable Road Users. 1. Introduction Deaths and injuries due to road traffic accidents occur worldwide. World Health Organization (WHO) [1] estimated that over 1.2 million people are dying every year on roads due to frequent road traffic accidents. Also World Health Organization (WHO) [1] reported that, a daily average of more than 3,200 people are dying and over 130, 000 sustain various degree of injuries in traffic accidents every day around the world and almost half of those affected by fatal accidents are vulnerable road users (pedestrians, cyclists and powered two wheelers). It is further reported that more than 85% of global accident fatalities occur developing countries such as Nigeria. Though road fatality rate in developed countries has been in decrease over the last decades, still road traffic accidents remain one of the main causes of death, injury and disability in these countries. Make Roads Safe [2] reports that unless there is concerted action taken, the road traffic accident fatalities are expected to increase globally by more than 65% between year 2000 and 2020, with different trends across the different regions of the world. Furthermore, the accident fatality in developing countries are predicted to be increased by more than 80%, but in developed countries is to be decreased by nearly 30%, thus revealing a widening gap between the road safety practice in developed and developing countries. A Road death around the world by level of income is shown in Figure 1. 55

2 Figure 1: Road deaths by country level of income (WHO 2009). 11% 43% 46% High Income Countries Low Income Countries Medium Income Countries While in many high income countries road fatality rates have stabilized or decreased, on the other hand, Currently in Africa the number of people dying due to road traffic accidents is constantly on increase and if this trend is allowed to continue without action, traffic accident related deaths may take the fifth place in the list of death causing, health disorders and injuries by the year 2030 and could result to an estimated fatalities per year of 2.4 million as shown in Figure 2. Figure 2: Number of road deaths per year (million) without action (WHO 2009). Road traffic accident is equally prevalent in developing countries such as Nigeria. The problem of road accidents in Nigeria has reached such alarming proportions; highways have been converted into death zones, killing citizens daily. According to Federal Road Safety Commission [3] report 12,969 people died, over 25,752 persons sustained various degrees of injuries and 7,517 people are left permanently disabled due to road traffic accidents across highways in Nigeria. Despite the annual road safety campaigns, warning against reckless driving and prosecuting offending drivers road traffic accidents have become the leading cause of loss in both human and material resources in Nigeria. Deaths due to vehicle accidents constitute a great economic loss to our society. Accidents have far reaching effects on families life, on development and economic life of the country. The strained health services available in the country are ill equipped to adequately look after traffic accident victims and thereby results in high number of death due to accidents. This brings grief and economic hardship to the victims families and accident survivors. Road traffic accidents involve physical, emotional, social and economic implications. The global economic cost of road traffic accident was estimated to be 518 billion USD per year in 2003 with over 100 billion USD of that occurring in developing countries such as Nigeria. Labinjo, et al. [4] reported that Nigeria annually loses 80 billion Naira (4.9 billion USD) to road traffic accidents. Therefore, prevention of road traffic accidents is important because road traffic deaths and injuries in year 2020 will exceed HIV/AIDS as a cause of death and disability [5]. 56

3 1.1 Objective of Research The objective of the research is to carry out a road safety audit on a Segment of A2 Expressway in Nigeria between Kano and Zaria and to assess the safety performance of the Highway segment. This is with a view to proposing appropriate counter measures to improve safety on the highway. 2. Literature Review The costs of Road Safety Audit (RSA) varies greatly depending on the project size and construction phase in which the audit were conducted. But the immediate benefit of road safety audit is accident prevention. However, several long term benefits exist which includes highway design and construction management team skills improvement, reduction in whole-life cycle cost of roadway schemes, good safety engineering practice and recognition of road users safety needs and improvement of design standards for good safety. Other benefits of RSA are reduction in risk of crashes and the repair works, a better quality in design processes, Provision of better facilities for vulnerable road users, and above all contribution towards achieving road safety targets through better standards and design guidelines, Gadd [6]. A study in conducted in Denmark [7] which focused on 13 projects, the number of crashes before and after RSA was conducted were estimated. The savings on crash costs after RSA resulted in a costbenefit ratio of 1:1.46. Also [8] focused on projects in which no RSA had taken place and where RSA was implemented in the initial design, the number of crashes prevented was estimated, resulting in a cost benefit ratio of 1:1.2. A study conducted by Surrey County Council [9] compared 38 reconstruction projects where by half are been subjected to RSA and the other half do not. The results recorded an annual average number of casualty reduction of 1.25 on the roads where RSA had been applied, while an annual average number of casualties reduction of 0.26 was recorded on roads where no RSA had been applied. Also Macauley and Mclnerney [10] studied another nine Australian RSAs conducted on the design stage. The cost-benefit ratios of RSA implementation were all positive and amounted to between 1:3 and 1:242 per project. 3. Methodology For the purpose of this research a 50 km section of Kano-Zaria expressway which is an existing roadway in Nigeria is considered as a case study. The road is a dual carriageway which connects two major cities with high population in Nigeria. It is also the main artery which connects the southern and northern parts of Nigeria. After the audit route was determined and selected, road safety audit was carried out based on the Federal Highway Administration [11] Road Safety Audit Guidelines. All necessary information and data required about the route were collected from relevant authorities before going to the site for observations. After gathering all those information audit surveys on the case study route were started from Naibawa interchange which was selected as a starting point and marked as km. Photographs and video records were also made during the site visits which are used for subsequent comments and discussions on observed hazards during the field survey. Both sides of the audit route were observed and all safety audit aspect of the road was recorded during the site survey on a safety audit checklist created for the existing road. After the hazards were identified during the inspection, the expected crash to be caused by each hazard was also clarified. Thus its risk and severity were also estimated. The resulting risk level was then identified using risk matrix [12]. Base on the risk level a countermeasure was proposed to mitigate the perceived risk. Also after comparison with design standard, the entire roadway elements observed were examined to assess for their effectiveness and compliance with the AASHTO highway design manual [13]. Each roadway element was assigned a score ranging from 1-10, with one being the worst score and 10 having the highest score. At the end the overall score for the road was obtained using a weighted average. 4. Results and Discussion In order to form an opinion on the geometric characteristics of the study route, a comparison was made between the study data and the AASHTO highway design manual [13]. This is to see if the geometric standards observed on the study route are adequate from a safety standpoint. The observed road features are compared with the AASHTO standard and shown in Table 1. 57

4 Below Average Average Above Average Good Very good Excellent Noble International Journal of Scientific Research Table 1: Comparison of observed road features with AASHTO standard No Roadway Element AASHTO Standard Values Observed Values 1 Design speed km/hr Depending on the terrain 100 km/hr 2 Number of lanes Four or more Four lane 3 Travel lane width 3.6 m minimum 3.3 m 4 Right shoulder width 2.4 m m 5 Left shoulder width m m 6 Turn lane width 3.6 m Median width including left Wide median 7.5 m minimum 4.0 m shoulders 8 Roadside clear zone 9 m Fill/Cut slope 4H:1V 5H:9V 10 Minimum bridge vertical 6.0 m 4.5 m clearance 11 Bridge width At least full approach traveled way width or plus 0.6 m clearance on each side 12 Control of access Partial/by regulation Uncontrolled access 13 Alignment Adequate and smooth flowing alignment Poor alignment 2/3 of traveled way width 14 Bus turnouts A well-marked widened shoulder or an independent turn out is highly desirable and should be provided at locations where there are known concentration of passengers No shoulder independent turnout 15 Pedestrians crossing Controlled Uncontrolled widened or The road safety audit performances of Kano-Zaria Road are shown in Table 2. The highway performed in the areas of Design speed and speed limit message posting, number of lane provisions, Median height provision, and vertical alignment design. It performed moderately in the areas of bridge width and vertical clearance provision, lane, shoulder and median width provision. Table 2: Road Safety Audit Evaluation General Notes: Only elements witnessed on the road were scored SCORING Notify road authority Roadway Element Score NOTES Speed Design 8 Speed is appropriate at some locations on the road Limit 10 Bridge Vertical 5 Clearance Bridge with and vertical clearance not sufficient Width 5 Lane Number 8 Lane width not sufficient Width 5 Shoulder Right width 5 Shoulder also not sufficient Left width 5 Median Width 5 Median width not sufficient Height 9 Access Control 5 Access are not controlled Alignment Vertical 8 Alignments are not smooth Horizontal 6 Clear zones Roadside 3 No roadside clear zone Area Bus Stop Bus Turnout 3 Bus stops were not properly located 58

5 Road Design Hazards Noble International Journal of Scientific Research Pedestrian Crossing Grade Separated 1 All pedestrian crossings are uncontrolled Grand Total= 91 N =16 Final Score = 5.7 N= Number of scored Items Access control to the facility was also moderately scored. However, the facility failed the assessment in the clear zones area, location of bus stops, and control of pedestrian crossing. The overall assessment gave a score of 5.7 indicating a low audit performance of the road. The safety risks associated with the road together with the proposed countermeasures are shown in Table 3, while the frequency distribution of the hazards and risks are shown in Figure 3. Table 3: Risk Level Assessments with Countermeasures Safety Hazards Expected Crash Recommended Counter Type Frequency Severity Risk level Measures H1-Missing Rear-end 2 2 Low Shoulders should Shoulder Collision reconstructed and paved H2- Junction Design H3- connection to shops/petro l Stations H4- Connection to small access road H5- connection to Roadway H6- Median opening H7-Limited sight distance H8- pedestrian crossing H9-Speed Limit too low H10- vertical sign H11- potholes where missing. All 1 5 Medium Junctions should be designed in accordance with the standards. All types of swipe 2 2 Low All connections should be designed in accordance with the standards. Head-On 1 4 Low All access road should be connected in accordance with the standards. head collisions on 1 5 Medium All connections should be designed in accordance with the standards. Rear-end 1 3 Low Turn lane should be provided. Head on, rearend collision Vehiclepedestrian collision 1 5 Medium Horizontal and vertical alignments should be designed as provided in the design manual. 2 5 High All pedestrian crossings should be controlled. Rear end 1 3 Low Traffic flow should not be disturbed. All types of swipe and collision 1 5 Medium All signs should be placed as specified in MUTCD. All types 5 5 Very high Proper and regular maintenance should be 59

6 Road Side Area Hazards Noble International Journal of Scientific Research Safety Hazards Expected Crash Recommended Counter Type Frequency Severity Risk level Measures applied. H12- Striking 4 3 High Provide a safety zone that Dangerous object is free of any obstacle. fixed object on the road side H13- Temporary road narrowing H14-Fixed massive poles near road or in the median H15-Road edge deterioratio n H16-Trees within safety zones H17- Dangerous free stones/rock s H18- Dangerous support for signs H19- Buildings close to the road H20-Steep edge slope without guard rail H21- Dangerous guard rail start and end H22- commercial activities on the road side H23- Sideswipe same direction, head on opposite direction Colliding with the object. 1 5 Low Road should not be narrowed, wherever it narrows necessary signs should be placed. 5 3 High Roadside or median should be free of any obstacle. Run off 2 4 Medium Provide paved shoulder. Collision with road side object Collision with road side object Collision with road side object 1 4 Low All trees with diameter greater than 10cm should be removed from the safety zone. 1 4 Low No object should placed on the safety zone. 2 4 Medium All supports should be guarded with guard rail/crash cushions. All types 3 5 High All building should be located far from the roadside. Runoff 1 5 Medium Provide guard rails where required. Head collision with guard rail All types of collision 1 3 Low All guard rail edges should be designed as specified in the standard. 2 5 High Relocate commercial to a more proper places. Sideswipes 1 2 Low A well-marked widened shoulder or an 60

7 Frequency Noble International Journal of Scientific Research Safety Hazards Expected Crash Recommended Counter Type Frequency Severity Risk level Measures bus stop independent turn-out design or should be provided at location locations where there are known concentration of passengers H24- Missing All types of collision 2 5 High All vertical and horizontal signs should be provided road sign throughout the road H25-Use of nonstandard sign All types of accident section. 2 5 High All signs should be standard Figure 3: Hazards Distribution over the Road Section The hazard distributions along the facility indicate that potholes and obstructions in the safety zones are the commonest hazards on the section studied. Also building lines close to the facility contribute immeasurable risks to vehicles and pedestrians. Objects fixed to the road sides especially the shoulders, do not allow room for vehicle recovery should a driver loses control or require to attend to the vehicle. The hazards identified broadly fell into two categories; Road Design hazards and Roadside hazards as shown in Figure 4. The road design hazards constitute 74percent of the risks while road side hazards take the remaining 26percent. 600 Figure 4: Hazards Classification Road design road side 61

8 Figure 5: Risk Level 4% 40% 31% 25% Very High high Medium Low In terms of the level of risks, four levels of risks were identified as in Figure 5. Very high risks constituted 4percent of the total risks while high and moderate risks take 28 percent each and low risks are 40percent of the observed risks. The conditions of the road depicting some of the observed risks are shown in figure 6 through 9. Figure 6: Potholes on the pavement (Km 9+00) Figure 7: Bus-Stop / Commercial Activities on the road side (Km 6+800) 62

9 Figure 8: Connection to Petrol Station (Km 3+400) Figure 9: Dangerous Road Narrowing (Km 0+300) 5. Conclusions This paper discussed Road Safety Audits (RSA) as a safety improvement technique with the aim of identifying hazards associated with the roadway and proposing for possible countermeasures appropriate for each hazard observed. After all the analysis, the overall roadway section evaluated had a score of 5.7 showing that the overall effectiveness of the road is below average and so much has to be done like immediate repairment of potholes to improve the condition of the road. It is also recognized that the most common hazards observed are fixed massive objects within the safety zone area, deficient guardrails, pavement damages like potholes and edge deterioration, missing shoulders, improper pedestrian crossings, improper commercial and improper bus stop locations, activities which indicates that majority of the hazards observed are associated with road design. References [1] World Health Organization (WHO), "Global status report on road safety, Geneva," [2] Make Roads Safe, "A new priority for sustainable development commission for global road safety," [3] Federal Road Safety Commission, Journal of accidents statistics and prevention, Publication of federal road safety commission Nigeria, 4 th ed.,

10 [4] M. Labinjo, C. Julliard, O. C. Kobusingye, and A. A. Hyder, "socioeconomic impact of road traffic injuries in West Africa: Exploratory data from Nigeria," Inj Prev, vol. 16, pp , [5] United Nations General Assembly Verbatim Report, "Meeting 38 session 60," pp. 6-26, [6] M. Gadd, Contract reports methods for determining the benefits of safety audit: a scoping study. Transfund New Zealand, Wellington, [7] DRD, "The safety audit project-evaluation, external panel s report. Danish Road Directorate DRD Copenhagen," [8] H. R. Al-Masaeid, "Effectiveness of road safety audit. VTI Konferens No. 10A, Part 1," in Proceedings of the conference road safety in Europe, Bergisch Gladbach, Germany, 1998, pp [9] Surrey County Council, "Road safety audit (An investigation in to the casualty savings report) surrey county council highways management division," [10] J. Macauley and R. Mclnerney, Evaluation of the proposed actions emanating from raod safety audits. Sydney: Austroads, [11] Federal Highway Administration, "Road safety audit guidelines, FHWA SA making your road safer," [12] Road Traffic Management Corporation South Africa, South African road safety audit manual, 2 nd ed., [13] American Association of Highway and Transportation Officials (AASHTO), Geometric design of highways and streets, 5 th ed.,