Key Road Injury Prevention Interventions and Their Effectiveness in Africa: Conclusions and What Can Be Done Better ()
1. Introduction
Road traffic injuries are a serious public health and safety problem. They are the eighth leading cause of death worldwide and the leading cause of death among young people aged 15 - 29 years. The distribution of road traffic deaths by user group varies considerably between regions and countries [1] .
According to the World Health Organisation (WHO), premature deaths and disabilities due to non-communicable diseases and injuries can be largely prevented by taking low-cost, effective and proven measures. To reduce the scale of road traffic injuries, WHO recommends that countries accelerate the pace of legislative reform, improve enforcement and focus particularly on vulnerable road users, such as pedestrians, cyclists and motorcyclists. It also recommends, in its Global Plan for the Decade of Action for Road Safety 2011-2020, raising awareness of measures to prevent road traffic injuries and promoting good practices such as helmet and seatbelt use, moderate speed, abstinence from alcohol, and good visibility in traffic [2] . In order to comply with the WHO’s recommendations, various measures are being implemented in countries to contribute to the common objective of reducing road deaths.
Several studies have been carried out worldwide to evaluate these different measures and have found that most of them help reduce accidents, their severity or fatalities. Very few of these studies have been conducted in Africa. To help guide priorities for road safety policy and research strategies, it is useful to learn from effective road safety interventions implemented in Africa for the prevention of road crashes, injuries, disabilities, and deaths. To this end, this study, based on a systematic review, aimed to identify road safety interventions implemented in Africa and to analyse their effectiveness in reducing road crashes, injuries, disabilities, and deaths.
2. Methods
2.1. Search Strategy and Selection Criteria
Protocol and registration: The presentation of the systematic review followed the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) grid [3] , and the protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO) database under the number PROSPERO 2019 CRD42019118801 available on: http://www.crd.york.ac.uk/PROSPERO/display_record.php?ID=CRD42019118801.
Eligibility criteria: Articles included were those relating to the evaluation of road safety interventions implemented in Africa, published in English or French and for which full versions were available. These articles covered a range of interventions such as the adoption or revision of a law, controls or enforcement measures to prevent speeding and alcohol, the use of protective equipment (helmets, seatbelts, child restraints), user awareness, user (driver) training, school education (school modules), distribution of protective equipment, improvement of road conditions, and traffic control.
Abstracts without full articles, literature reviews, systematic reviews, meta-analyses, commentaries, and articles with unworkable data (not available in French or English) were excluded.
Information sources: Articles were searched on electronic databases: PubMed, Scopus, Lissa, Google Scholar, and African Journals Online.
Article search strategy: Articles were retrieved from 22 to 27 February 2019 using search equations tailored to each database. Two pairs of reviewers were formed to independently conduct the article selection and data extraction.
2.2. Data Analysis
Article selection: For the selection, all articles from the database search and their abstracts were imported into EndNoteX9 regardless of the language of the full text. Each reviewer examined the articles on their own and then reviewed them within the pair and between the pairs to compare the articles selected. Different steps were followed, namely the elimination of duplicates, the exclusion of abstracts and other articles that did not meet the inclusion criteria, the exclusion of articles on the basis of the title and abstract, and then on the basis of the full text.
Data extraction: For this purpose, an Excel tool was designed containing information on the title of the study, the references (journal, year, publication number), the authors, the country, the type of study, the types of road safety interventions, the users involved, the outcomes to be measured, the duration of the intervention, and the assessment of the quality of the data.
Quality of the studies: Data quality was checked according to the type of study. Different approaches were used: 1) Strengthening The Reporting of OBservational Studies in Epidemiology (STROBE) indicators were checked for cross-sectional studies [4] ; 2) for case-control and cohort studies the Newcastle-Ottawa Scale (NOS) scale was complemented with the STROBE indicators [4] [5] ; 3) A Cochrane Risk Of Bias Assessment Tool for Non Randomized Studies of Interventions (ACROBAT-NRSi) scale [5] , and the Standard Protocol Items: Recommendations for Interventional Trials (SPRIT) guidelines for non-randomised trials and quasi-experimental studies [6] ; 4) the Cochrane Grading of Recommendations, Assessment, Development and Evaluations (GRADE) mechanism [7] , and the Consolidated Standards Of Reporting Trials (CONSORT) guidelines for randomised studies [8] . We assigned risk of bias as recommended by Cochrane, referring to the Cochrane Handbook (low, moderate, and high risk) [9] . The risk of bias is high if several indicators of bias are present on all scales; the risk is moderate when there is a single indicator of bias on several scales. It is low when all indicators measure low or no bias.
Type of data analysis: A qualitative analysis of the data was carried out and a narrative approach was adopted to describe and synthesise the results.
3. Results
3.1. Description of the Studies
At the end of the search, a total of 3106 articles were obtained of which 848 were from PubMed, 1262 from Scopus, 543 from AJOL, 332 from LiSSa, and 121 from Google Scholar. The selection process resulted in twenty-nine articles (Figure 1).
The extracted data were presented according to the characteristics of the studies (Table 1). Considering the type of study, twenty-one articles were quasi-experimental studies, six of which were randomised and fifteen non-randomised. One study was cross-sectional and seven were time series.
The type of intervention evaluated was varied. Two studies concerned institutional strengthening [10] [11] . Nine interventions concerned law enforcement, including two on helmet wearing [12] [13] , one on seatbelt wearing [14] , three
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Figure 1. Flow chart showing the process of identifying and selecting studies for inclusion in the review.
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Table 1. Characteristics of the articles included in the systematic review.
on speed limits [15] [16] [17] , one on alcohol and other road safety measures [18] , one on banning motorbikes from the capital [19] , and one on banning the use of motorbikes as a means of public transport [20] . Eight studies concerned awareness raising, training, or user education interventions [21] - [28] . One study concerned the development of an Uber transport service in South Africa [29] , and one concerned the distribution of helmets and reflective vests [30] . Eight studies combined several interventions such as enforcement, monitoring, education and awareness raising, provision of equipment (helmets and hairnets), vehicle maintenance, and infrastructure improvements [31] - [38] .
The users benefiting from these interventions were pedestrians (three studies), drivers or passengers of two- or three-wheeled vehicles (eight studies), drivers or passengers of vehicles with more than three wheels (nine studies), all motorised vehicle users (two studies), or all types of users (seven studies).
The expected outputs or outcomes of these studies were diverse. These included a reduction in road traffic fatalities, injuries, crash cases, or emergency room admissions for trauma. Other outputs included reductions in the severity of road crashes, hospital stays, or speeding. Some outputs were related to helmet use, improved knowledge and behaviour regarding traffic rules, laws and protective measures, or insurance claims data (Figure 2).
In the implementation, twenty-two studies involved interventions that were implemented for three months or more, while six interventions were one-offs lasting less than a week, and one intervention was repeated more than once.
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Figure 2. Different expected outputs of the evaluated interventions.
The risk of bias was assessed as high for twelve studies, moderate for thirteen, and low for four. No studies were excluded due to risk of bias.
3.2. Summary of Results
The results obtained have been presented by intervention (Table 2). Most of the interventions implemented showed evidence of effectiveness in terms of the results obtained. Indeed, for fourteen studies all the expected indicators had changed favourably and for eleven the indicators had partially changed. Only four studies did not show the expected main results. The studies that showed significant change were institutional strengthening [10] [11] , law enforcement [15] - [20] , awareness raising, training, or user education interventions [21] - [28] , development of Uber transport services [29] , distribution of equipment [30] , and a combination of interventions [31] [33] - [38] . The studies were randomised [22] [23] [26] [27] [28] [30] , non-randomised [15] [16] [17] [19] [21] [24] [25] [33] [35] [36] [38] , time series [10] [11] [18] [20] [29] [31] [37] , or cross-sectional studies [34] . The inconclusive studies were non-randomised [12] [13] [14] [32] . Of them, three were law enforcement studies [12] [13] [14] , and one combined several interventions [32] .
Countries of studies implementation: Nigeria (twelve studies), South Africa (seven studies) and Kenya (five studies) embedded more than 80% of studies selected (Figure 3).
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Figure 3. Countries of implementation of the evaluated interventions. Data source: GADM.org (contour and cutting of Africa). Copyright holder: BHDS.
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Table 2. Interventions implemented, and results obtained.
Institution building studies: The two studies concerned were implemented in Nigeria and assessed the influence of the creation of a road safety institution on the trend in road crashes, injuries and deaths. Both studies found a significant reduction in road crashes and injuries according to the indicators measured (average annual number for one, proportion and number per capita for the other) [10] [11] . However, while one study found a significant reduction in fatalities [11] , the difference was not significant in the second study [10] .
Law enforcement studies: Five of these interventions improved all the indicators predicted by the studies [15] [16] [18] [19] [20] , while one improved partially indicators [17] , and three were inconclusive [12] [13] [14] . The implementation of these laws resulted in a reduction in the frequency and severity of injuries [13] [15] - [20] , a significant decrease in the hospital prevalence of road traffic accidents (RTAs) [20] , a decrease in RTAs resulting from motorbike collisions [19] , a reduction in mean speed [17] , an increase of subjects wearing helmets [12] , a reduction of passenger vehicle crash [17] , a decrease in road traffic deaths [16] [17] [18] [19] , and a reduction in the total length of hospital stay for patients admitted for head injury after an RTA [16] . The laws concerned were speed limits [15] [16] [17] , alcohol control [18] , helmet use [12] , a ban on motorbikes in the capital [19] , and a ban on the use of motorbikes as a means of public transport [20] . In contrast, evaluation of the influence of helmet enforcement in Nigeria, rather than a reduction, noted an increase in the proportion of motorcyclists who died from RTAs after the intervention [12] . Furthermore, they were no improvements in helmet use among motorcycle drivers and passengers after helmets enforcement in Kenya [13] , and non-significant reduction in accident cases after seat-belt enforcement in Nigeria [14] . Authors of these studies believed that the influence of other confounding factors as lack of education on the correct use of the crash helmet, or differences in population in different periods were responsible for these outcomes. Opportunity to further increase both awareness as well as enforcement of the legislation would improve outcomes of law enforcement.
Studies on awareness raising, training or user education interventions: Four studies noted the achievement of all expected outputs [23] [25] [27] [28] , and for another four, there was partial achievement [21] [22] [24] [26] . Training drivers in rescue techniques, basic evacuation procedures and specific first aid skills resulted in a significant increase in the first aid knowledge score in the intervention group [22] as well as in the first aid skill score [22] [23] . However, the knowledge score was not improved in one of the two studies that evaluated this intervention [22] . Similarly, the intervention to improve knowledge of traffic signs resulted in a significant change in learners’ or drivers’ knowledge after the intervention [21] [25] , and a significant increase in the proportion of drivers reporting compliance with traffic signs in the group [25] . However, the effects varied according to the categories of traffic signs [21] .
Communication about road safety practices led to some expected results, such as an increase in the proportion of drivers reporting resting after hours of driving or observing speed limits, and a decrease in the proportion of drivers reporting fatigue. This study did not find significant differences in the possession of a valid driver’s licence, substance use, carrying more than one person, and a decrease in the prevalence of RTAs [24] .
Health and safety education on various road safety topics resulted in a significant increase in the proportion of drivers with correct knowledge of licensing requirements, and adequate knowledge of road signs and maximum speed limits in the intervention group. However, the proportion of drivers reporting compliance with speed limits in the intervention group decreased [26] . The introduction of stickers in public transport vehicles led to a reduction in the number of incidents resulting in insurance claims [27] [28] . Stickers had messages encouraging passengers to react if the driver did not follow the rules of the road, to report it [27] [28] , or messages on the possible consequences of driver misbehaviour if the driver did not listen to the advice [28] . There was also a reduction in the average maximum speed of drivers in the intervention group, a reduction in crashes (140 fewer RTAs) and fatalities (55 lives saved) [28] .
Study of the development of Uber transport services: This intervention resulted in a slight reduction in weekly RTA deaths in the province with Uber in South Africa compared to provinces without Uber [29] .
Equipment distribution study: Free distribution of reflective vests, combined with brief road safety education in Tanzania, led to a significant increase in the use of reflective vests among motorbike taxi drivers. However, there was no significant change in the use of white helmets and daytime running lights among motorbike taxi drivers [30] .
Multi-intervention study: The combination of various interventions among public transport drivers in Kenya did not result in significant changes in injury severity levels (including fatalities) or patient hospital stays [32] . A combination of interventions to reduce the risk of accidents among schoolchildren resulted in a decrease in the prevalence of RTAs, the frequency of pedestrian-car collisions among schoolchildren, and the frequency of minor injuries in the intervention group [35] [37] . There was a non-significant decrease in the frequency of pedestrian-motorcycle collisions (the most frequent type of collision) in the intervention group [35] , and in the number of motor vehicle collisions in one of the two zones, but an increase was recorded in the second zone [37] . These interventions reduced the frequency of speeding, braking, and sudden acceleration among drivers in the intervention group, but they drove more at night [36] . The construction of a footbridge and educating schoolchildren to use it in Nigeria showed a “significant” increase in the number of pupils using the footbridge to cross the road [38] .
Studies evaluating the effectiveness of the enforcement of various road safety laws and the monitoring of compliance have shown reductions in fatalities in terms of lives saved [33] , or reductions in fatalities per 10,000 vehicles [31] . There was also a significant reduction in the number of non-injury RTAs, but the number of injuries per 10,000 vehicles did not decrease as expected [31] . A study implementing activities to increase compliance with road safety measures and encourage helmet use resulted in improved helmet use (reported or directly observed), reduced prevalence of RTAs, speeding, carrying more than one passenger, and an increase in the proportion of subjects reporting protective behaviours [34] .
4. Discussion
Very few studies have been carried out on road safety in Africa and the majority are concentrated in three countries. It can also be noted that it is mainly English-speaking countries that have published on implemented interventions. This shows that French-speaking countries seem to be behind in terms of research and scientific publications on road safety. Studies that measured effects on the reduction of accidents, injuries, or deaths used various indicators of absolute frequencies in some cases, such as the frequency of injuries [17] [20] , number of weekly deaths from RTAs [29] , annual number of RTAs, injuries, or deaths [11] , number of RTA cases [17] [19] [28] , total number of patients admitted with head injuries after RTAs, or deaths in patients admitted with head injuries after RTAs [16] . Some studies have assessed injury severity levels [15] [19] [20] [32] . Others have determined the length of hospital stay for patients [16] [32] , or the number of lives saved [28] [33] . The absolute frequency measure for judging the effectiveness of an intervention seems insufficient because it does not consider a denominator that could better compare two different periods or different contexts. This means that assessments of the effectiveness of the interventions concerned are questionable.
Some studies measured indicators that are relative frequencies such as proportions, ratios, prevalence, incidences, and others. In this group, we can mention the annual average number of RTAs, people injured or killed after an RTA [10] , the number of RTAs, serious RTAs and fatal RTAs per capita [11] [14] , the monthly number of RTAs, people injured or killed after an RTA per 10,000 vehicles [31] , the prevalence of RTAs [34] [35] , the hospital prevalence of RTAs [20] , the incidence of trauma [15] , the ratio of fatalities per crash involving motorcyclists [12] , the median number of pedestrian-vehicle crashes per km of road per year, the median number of motorcycle-vehicle crashes per km of road per year [37] , the ratio of the total number of RTAs, or fatal RTAs per volume of petrol sold [18] . These types of indicators seem more realistic as a measure of effectiveness and for comparing the same types of intervention in different contexts or time periods. Indeed, use of indicators based on ratios or relative frequencies is more relevant than the use of absolute frequencies, as the inclusion of a denominator makes it possible to standardise interpretation and comparison between before and after the intervention.
The studies of user awareness, training, or education interventions [21] - [28] , the study of equipment distribution [30] , and two studies combining several interventions essentially assessed outputs related to the adoption of certain behaviours [36] [38] , but not effects on injury or fatality reduction. These indicators do not assess the effects of the implementation of these measures on accidents, injuries, or fatalities. The only study of an awareness intervention that looked at effects measured absolute frequencies only (reduction in RTAs and number of lives saved) [28] , which is also a shortcoming.
The studies on institutional strengthening all seem to be effective, as they have noted a significant reduction in road accidents and injuries [10] [11] . The same is true for most of the enforcement studies, which have shown a reduction in the frequency and severity of injuries [15] - [20] , except for the three studies on helmet and seatbelt use [12] [14] . Both of these studies showed convincing direct effects (helmet or seatbelt use) but not a significant effect on the occurrence of injuries and fatalities. This could be explained by the existence of other accident severity factors not considered by these studies. The combination of various interventions led to a reduction in road accidents, injuries and/or deaths [31] [33] [35] [37] , except for one study [32] . This observation demonstrates the value of implementing integrated and multidisciplinary interventions.
Limitations of this study: The risk of bias was assessed as high for several articles, but these were not rejected so as not to reduce the number of articles too much. Also, the interventions and the methodologies were diverse, as were the outputs, which limits the comparison of studies. However, we considered that studies that demonstrated a reduction in road traffic accidents, injuries or deaths could be retained as effective studies. Several studies measured only intermediate outcomes but not the effects of interventions on reducing road traffic injuries and fatalities, which does not confirm their effectiveness.
5. Conclusion
Few countries have conducted studies to measure the effect of road safety interventions in Africa. It is important to assess the effectiveness of interventions in order to know which ones to promote, based on their cost-effectiveness, and which ones to reorient in relation to the contexts of each country. This systematic review shows that the most effective interventions are those related to institutional strengthening, law enforcement and, above all, the combination of several interventions. Research is needed to measure the effect of awareness, education, and training interventions on the occurrence of RTAs, injuries, and deaths from RTAs. Leading road safety institutions and all stakeholders should encourage and fund research to evaluate measures implemented in countries and to conduct quasi-experimental intervention studies tailored to each context.
Acknowledgements
The research team would like to thank the authorities of the Regional Institute of Public Health. The following people who have contributed or facilitated the achievement of this research are also thanked for their contributions: Ms. Valérie DURIEUX, librarian at the Université Libre de Bruxelles, who helped to determine the main terms used in the research equations and to formulate these research equations; Prof. Katia CASTETBON who contributed to the definition of the methodology of the study and to the development of the tools for data extraction; Mr. Dosten Kpozehouen and Mr. Nicolas Gaffan who participated in the selection of articles and the extraction of data; Dr. Virginie MONGBO who guided the writing of the article.