Prevalence, Sociodemographic and Traffic Factors Associated with Fatal Pedestrian Road Accidents in Nairobi, Kenya: An Autopsy Study ()
1. Introduction
Pedestrian road traffic fatalities are a major global public health concern, constituting nearly 25% of all road traffic deaths worldwide [1]. Alarmingly, about 90% of these fatalities occur in Low- and Middle-Income Countries (LMICs), with the African region bearing over 40% of the total burden [2] [3]. In some African countries, pedestrians account for as much as 80% of all road traffic deaths. Sub-Saharan Africa (SSA), including Kenya, continues to experience high and rising rates of pedestrian fatalities [4] [5].
The prevalence and characteristics of pedestrian road traffic deaths vary both between and within regions. These differences are influenced by numerous factors, including the quality of road infrastructure, urban planning, population density, vehicle types and volumes, enforcement of traffic regulations, public awareness, and broader socio-economic conditions [3] [6]. Understanding these factors is essential for designing effective and context-specific interventions, including improvements in urban planning, pedestrian infrastructure, traffic law enforcement, and healthcare preparedness.
In Kenya, the burden of pedestrian deaths is disproportionately high in urban centers, particularly in Nairobi. This has been attributed to rapid urbanization, poor road design, limited pedestrian facilities, increased motorization, and a lack of traffic discipline. The state of road infrastructure across SSA, including Kenya, has been cited as a major contributing factor to the high rates of pedestrian fatalities [5] [7]. Despite this burden, few studies—particularly autopsy-based investigations—have systematically examined the sociodemographic and traffic-related patterns of fatal pedestrian crashes in the country.
This study therefore aimed to determine the prevalence of pedestrian fatalities in Nairobi and to describe the associated sociodemographic and traffic factors. Additionally, it sought to assess the role of alcohol intoxication among victims through forensic toxicological analysis. Generating such localized data is crucial to inform evidence-based strategies, policies, and interventions that improve pedestrian safety and reduce preventable deaths on urban Kenyan roads.
2. Materials and Methods
This was a prospective descriptive autopsy-based study carried out over a one-year period from June 1, 2009, to May 31, 2010, at Nairobi City Mortuary. The mortuary, located at the junction of Mbagathi Way and Ngong Road, is the largest public mortuary in Nairobi and serves as the principal center for medicolegal autopsies, receiving approximately 200 bodies of each month. The study was designed to examine the prevalence and patterns of violent deaths and relationship with alcohol intoxication. Violent deaths in this context included fatalities resulting from homicide, suicide, and accidents—where accidents referred to both road traffic and other unintentional injuries. In road traffic cases, the categories of persons involved included pedestrians, drivers, passengers, and cyclists.
Ethical approval for the study was granted by the University of Nairobi-Kenyatta National Hospital Ethics and Review Committee (Ref: KNH/UON-ERC/A/ 196), and informed consent was obtained from the next of kin of the deceased. The prevalence of pedestrian deaths was calculated using Nairobi’s population of 3.7 million, as reported in the 2009 National Census. Demographic details such as age and sex were obtained from next of kin and verified using official identification documents. Individuals were grouped into standard 10-year age bands ranging from 1 to 69 years for analytical consistency.
A total of 2,566 autopsies were conducted during the study period. From these, 929 deaths were attributed to road traffic accidents, of which 436 (46.9%) were pedestrians. To assess alcohol intoxication, a subsample of 400 cases was selected using a systematic sampling approach. Specifically, every fifth case was chosen consecutively, yielding a preliminary sample of approximately 539 individuals. From this pool, the first 400 cases were ultimately analyzed for alcohol levels. This method offered a balance between representativeness and feasibility, as full toxicological testing on all 2,566 cases was not financially or logistically viable. Systematic sampling preserved proportionality while ensuring manageable laboratory workloads.
Alcohol testing was performed using vitreous humor samples collected during postmortem examination. Ethanol levels were measured using gas chromatography (GC) with flame ionization detection (FID), in accordance with international forensic toxicology guidelines. The equipment used was a Varian Model 3700 gas chromatograph (Varian Associates, Georgetown, Ontario), employing helium as the carrier gas. Injector and detector temperatures were maintained at 100˚C and 140˚C respectively, and isothermal elution was used with n-propanol serving as the internal standard. A carbowax 20M high-polarity GC column facilitated accurate quantification of ethanol. Alcohol intoxication was defined as a blood alcohol concentration (BAC) exceeding 0.08 g/dL.
In the subset tested for alcohol, 43 were confirmed road traffic accident fatalities. Data were recorded on standardized data sheets and analyzed using the Statistical Package for the Social Sciences (SPSS) version 11.5. Descriptive statistics were used to generate frequencies and proportions, while Pearson correlation tests were applied to assess associations between alcohol intoxication and pedestrian fatalities, with statistical significance set at p < 0.05.
Detailed data on the site and circumstances of the accidents were obtained from accompanying police officers and case records. This included classification of the roads where accidents occurred. Roads were categorized by function and geographic context. Highways referred to major arterial roads designed for high-speed, long-distance travel, including Thika Superhighway, Mombasa Road, and Waiyaki Way. Market roads were located near high-density trading areas, typically with poor pedestrian infrastructure. City roads were found within the central business district and nearby urban zones. Estate roads were within residential neighborhoods, often with narrow lanes and slower speed limits. Town roads included those in peri-urban settlements such as Embakasi, Eastleigh, and Kibera, serving mixed residential and commercial functions. Other roads consisted of minor access paths, unpaved roads, and informal tracks, especially in industrial and peri-urban regions that did not fit into the other categories.
Additional variables included the class of vehicle involved in each fatality. This ranged from light passenger vans (matatus), buses, and trucks to private cars and motorcycles. Circumstances such as the pedestrian’s activity at the time of death—most commonly road crossing—were also recorded.
This multifaceted data collection enabled an in-depth analysis of the demographic, situational, and toxicological characteristics of pedestrian fatalities in Nairobi, and provided a robust foundation for assessing the relationship between alcohol intoxication and fatal pedestrian incidents in the urban Kenyan setting.
3. Results
3.1. Prevalence
Nine hundred and twenty-nine (929) cases of Road traffic accidents were studied. Pedestrians comprised 436(46.9%) of the cases followed by cyclists (234; 25.2%) then passengers (214; 23.0%). Drivers were least affected (45; 4.8%) (Table 1).
Table 1. Distribution of categories of road involved in fatal road traffic accidents in Nairobi, Kenya.
CATEGORY OF ROAD USER |
FREQUENCY (%) |
Pedestrian |
436 (46.9) |
Cyclist |
234 (25.2) |
Passenger |
214 (23.0) |
Drivers |
45 (4.8) |
TOTAL |
929 (100) |
The 436 cases of pedestrian fatalities translated to a crude prevalence of 11.8/100,000 inhabitants.
3.2. Age and Sex Distribution
The mean age was 30.0 years (range: 10 - 59). The most frequent age group was 30 - 39 years (211; 48.4%), followed by 20 - 29 years (117; 26.8%), 40 - 49 years (82; 18.8%), 50 - 59 (20; 4.6%), the least frequent age group was 10 - 19 (6; 1.4%).
Males predominated (404; 92.7%) giving a male to female ratio of 12.6:1. This male predominance persisted in all age groups. It was highest in the 30 - 39-year age group (22.4:1), followed by 40 - 49 (10.7:1) (Table 2).
Table 2. Age and sex distribution of pedestrians involved in fatal road traffic accidents in Nairobi, Kenya.
AGE RANGE |
NNUMBER/SEX |
M |
F |
TOTAL |
M/F RATIO |
10 - 19 |
4 |
2 |
6 (1.4) |
2:1 |
20 - 29 |
106 |
11 |
117 (26.8) |
9.6:1 |
30 - 39 |
202 |
9 |
211 (48.4) |
22.4:1 |
40 - 49 |
75 |
7 |
82 (18.8) |
10.7:1 |
50 - 59 |
17 |
3 |
20 (4.6) |
5.7:1 |
TOTAL |
404 |
32 |
436 (100) |
12.6:1 |
3.3. Circumstances of the Accident
Majority of the pedestrian fatalities resulted from pedestrians crossing the road (329; 75.5%), followed by motor vehicle veering off the road (72; 16.5%) and motor bike veering off the road (3; 58%) (Table 3).
Table 3. Circumstances of pedestrian in fatal road accident in Nairobi, Kenya.
CIRCUMSTANCES |
N0. OF CASES (%) |
Pedestrian crossing the road |
329 (75.5) |
Motor vehicle veered of the road |
72 (16.5) |
Motor bike veered of the road |
35 (8) |
TOTAL |
436 (100) |
3.4. Site of Pedestrian Road Traffic Accident
A majority of pedestrian accidents occurred on roadways. The most common site was highways (111; 22.5%), roads in markets (100; 22.9%), city center (75; 17.2%), residential areas (65; 14.9%), and towns (47; 10.8%). Off road or street settings were involved in 38 (8.7%) cases (Table 4).
Table 4. Site of pedestrian fatal road traffic accident in Nairobi, Kenya.
SITE |
NUMBER OF PEDESTRIANS (%) |
Highway |
111 (25.5) |
Market |
100 (22.9) |
City roads |
75 (17.2) |
Estates |
65 (14.9) |
Town Roads |
47 (10.8) |
Others |
38 (8.7) |
TOTAL |
436 (100) |
3.5. Class of Vehicle Involved
Pedestrian fatalities were largely contributed by passenger vans; matatus (155; 35.6%) followed by buses (108; 24.8%), heavy trucks (92; 21%) then personal cars (46; 10.6%). Motorbikes were the least involved (35; 8%) (Table 5).
Table 5. Class of motor vehicle involved in pedestrian road traffic accidents in Nairobi, Kenya.
CLASS OF VEHICLE |
N0 OF CASES (%) |
Light passenger van or minibus “Matatu” |
155 (35.6) |
Heavy passenger bus |
108 (24.8) |
Heavy trucks |
92 (21.0) |
Personal cars |
46 (10.6) |
Motor bike |
35 (8.0) |
TOTAL |
436 (100) |
3.6. Pedestrians’ Fatalities Relationship with Alcohol Intoxication
An analyses of alcohol intoxication amongst victims of road traffic accidents revealed that of the 43 persons who were intoxicated, there were 22 (51.2%) pedestrians.
4. Discussion
The prevalence of pedestrian road traffic fatalities varies significantly across regions and countries, largely due to differences in socioeconomic status, infrastructure quality, traffic regulation, and road user behavior (14). Socioeconomic factors impact mobility patterns, availability and condition of pedestrian infrastructure, vehicle types, and cultural attitudes toward alcohol use and risk-taking. This study provides new evidence on the characteristics of fatal pedestrian crashes in Nairobi, highlighting patterns that have not been previously documented. These findings offer important, localized insights that can guide the development of targeted, context-appropriate interventions aimed at improving pedestrian safety and reducing preventable deaths on urban roads.
4.1. Prevalence
According to the World Health Organization, pedestrians account for up to 40% of global road traffic fatalities [1]. This study found an even higher figure in Nairobi, where pedestrians made up 46.9% of all road traffic deaths. This is consistent with findings from Malawi (46.5%) and South Africa (43%) [7] [8], but significantly exceeds rates reported in high-income countries such as Sweden (18%), Turkey (15.6%), Poland (30%), India (10.5%), and Pakistan [9]-[13]. Even within Sub-Saharan Africa, countries like Ghana (36.7%) and Botswana (32%) report lower proportions [14] [15], although Ethiopia shows a much higher rate of 79.8% [5].
When assessed per capita, Africa’s average pedestrian fatality rate is about 3.4 per 100,000 people [16], but Nairobi reports a much higher rate of 11.78. This approximates the U.S. figure (12.7/100,000) but far exceeds rates in most high-income and MENA countries [17] [18]. Nairobi’s elevated figures likely reflect poor infrastructure, weak enforcement, and socioeconomic vulnerabilities [3] [19] (Table 6).
Table 6. Proportion of fatal pedestrian road traffic accidents in various countries.
Ref |
Country |
Percentage proportion |
Alemayehu et al., 2023 |
Ethiopia |
79.8 |
Amin et al., 2022 |
Sweden |
25.0 |
Budzynski et al., 2019 |
Poland |
30 |
Bullard et al., 2024 |
Ghana |
36.7 |
Geduld et al., 2024 |
South Africa |
43 |
Martinez et al., 2019 |
Latin America & Caribbean |
23.7 |
Mphela et al., 2021 |
Botswana |
32 |
Mwenda et al., 2018 |
Kenya |
36 |
Ngwira et al., 2019 |
Malawi |
46.5 |
Santa et al., 2024 |
Hungary |
34.6 |
Suleiman et al., 2022 |
Türkiye |
15.6 |
Sivasankaran et al., 2019 |
India |
10.5 |
Current study |
Kenya |
46.9 |
4.2. Age and Sex Distribution
The study found that the mean age of pedestrian fatalities was 30 years, with the 30 - 39 age group accounting for the highest proportion (48.4%) of deaths. This pattern is consistent with previous findings in Kenya, where the average age of pedestrian victims was reported at 35.7 years [20], and in the United States, where individuals aged 31 - 40 are most commonly affected [21]. These findings contrast with trends in many high-income countries, where pedestrian fatalities more frequently involve older adults. For instance, the median age in Sweden is 59.2 years, while in Spain, the most affected age group falls between 65 and 84 years [9] [22] [23].
A striking feature of this study is the overwhelming male predominance, with a male-to-female ratio of 12.6:1, reflecting similar patterns observed globally [21] [24]-[26]. This disparity may be attributed to higher male exposure to traffic environments, more frequent risk-taking behavior, and lower adherence to road safety regulations. The “Young Male Syndrome” hypothesis suggests a biological inclination among young men towards risk-taking, further increasing their vulnerability [27]. In South Africa, studies have also linked pedestrian deaths among men to poor compliance with traffic laws [28]. These findings underscore the importance of targeting young men in pedestrian safety campaigns and enforcement strategies.
4.3. Site and Circumstances of the Accident
In this study, a significant majority—76.4%—of pedestrian fatalities occurred on highways and major roads. This aligns with global findings showing that high-speed roads pose a heightened risk to pedestrians due to fast-moving traffic and limited crossing infrastructure [29]. Similar patterns have been observed across various regions, including Africa, Europe, the Middle East, and Asia, where high-traffic arterial roads are consistently associated with increased pedestrian mortality [9] [23] [30]-[32]. Over three-quarters of victims were struck while attempting to cross the road, reaffirming the global trend that road crossings are among the most hazardous pedestrian activities [30] [33].
Additionally, 16.5% of the fatalities involved vehicles veering off the road, highlighting infrastructural deficiencies such as the lack of adequate sidewalks or protective pedestrian barriers. Research shows that incorporating physical infrastructure—like rail guards, bollards, and designated footpaths—can substantially reduce the severity and frequency of pedestrian injuries [15] [18].
Residential estates and off-road areas accounted for nearly 24% of the fatal cases. This proportion mirrors U.S. data, where approximately 12% of pedestrian crashes occur in residential neighborhoods [29], with up to half of such incidents taking place near the victim’s home [16]. These findings illustrate that pedestrian risk is not confined to highways; it is also prevalent in community settings. This underscores the importance of implementing localized safety measures, such as traffic calming devices, safe pedestrian crossings, reduced speed limits, and improved neighborhood planning, to enhance pedestrian safety in both high-traffic and residential environments [25].
4.4. Class of Vehicle Involved
Light passenger vans, commonly known as matatus, were implicated in 35.6% of pedestrian fatalities in this study. Although other research more frequently identifies heavy vehicles, SUVs, and trucks as major contributors to pedestrian deaths [26] [31] [33], the prominence of matatus in Nairobi’s public transport system likely accounts for their high involvement. These vehicles dominate the city’s urban mobility landscape but are often associated with poor regulation, aggressive driving behaviors, frequent traffic violations, and chaotic route management [4].
The high fatality rate linked to matatus underscores the urgent need for targeted interventions in this sector. Effective mitigation strategies should include stringent regulatory reforms, mandatory and standardized driver training programs, and better enforcement of traffic laws. Additionally, rationalized route planning and the creation of dedicated lanes for public transport vehicles could help reduce pedestrian exposure, particularly in crowded urban corridors. Prioritizing these changes in high-density pedestrian zones could significantly enhance road safety [34].
4.5. Relationship with Alcohol Intoxication
In this study, over half of the pedestrian fatalities (51.2%) tested positive for alcohol—a figure significantly higher than reported in many other regions. For comparison, studies from Finland recorded alcohol involvement in 19.9% of pedestrian deaths, while the U.S. and South Africa reported even lower rates of approximately 22.35% and 6.4%, respectively [7] [23] [29]. This disparity is striking and raises critical concerns about the role of alcohol in pedestrian road traffic fatalities in Nairobi.
Alcohol consumption is widely recognized as a major risk factor for pedestrian injuries and fatalities. Intoxicated pedestrians are more likely to misjudge traffic gaps, walk unpredictably, and cross roads in unsafe locations, especially in high-speed or poorly lit areas [32] [33]. The high prevalence of alcohol among victims in this study likely reflects the demographic profile of the affected population—predominantly young males—who are both more likely to consume alcohol and engage in risky road-use behaviors.
Given this pattern, addressing alcohol-related pedestrian deaths requires a multifaceted approach. Strategies may include restricting the sale and consumption of alcohol in high-risk urban zones, particularly near busy roads or public transport hubs. Public education campaigns can also raise awareness about the dangers of walking while intoxicated, especially targeting young adults. Moreover, stricter enforcement of existing laws concerning alcohol use, including random breath testing and penalties for intoxicated pedestrians and drivers, could help deter risky behavior. Ultimately, integrating behavioral, legal, and environmental interventions is key to reducing alcohol-related pedestrian fatalities in Nairobi.
4.6. Limitations
While this study offers valuable insights into pedestrian fatalities in Nairobi, it has several limitations. Firstly, it was based on data from a single mortuary. Although this facility serves a large portion of the city, the findings may not reflect pedestrian deaths occurring in other regions or rural settings. Secondly, alcohol testing was conducted on only a subset of cases due to resource constraints. This may have led to either underestimation or overestimation of alcohol involvement among victims. Thirdly, the study lacked detailed contextual information such as time of day, lighting conditions, weather, and driver behavior—factors that could provide deeper understanding of crash dynamics. Lastly, the cross-sectional design limits the ability to draw causal inferences. Despite these constraints, the study contributes critical local evidence. Future research should incorporate data from multiple sites, include broader samples, and apply longitudinal designs to improve generalizability and identify causal patterns in pedestrian fatalities.
4.7. Conclusion
Pedestrian fatalities represent a significant share of road traffic deaths in Nairobi, accounting for nearly half of all such incidents. This high prevalence underscores a serious public health and urban planning challenge. The study revealed that young adult males are disproportionately affected, suggesting a vulnerable demographic shaped by greater exposure to traffic, risk-taking behavior, and frequent alcohol use. Most of these fatal crashes occurred during road crossings along major highways and high-speed roads—locations typically lacking adequate pedestrian infrastructure such as safe crossings, barriers, or footpaths.
Additionally, a substantial proportion of fatalities involved intoxicated victims, highlighting alcohol use as a critical risk factor. The combination of risky pedestrian behavior, poor road design, and insufficient enforcement creates a hazardous urban environment, particularly for those in socioeconomically disadvantaged areas.
To effectively reduce pedestrian deaths, a comprehensive and multi-sectoral response is essential. Priorities should include redesigning road infrastructure to accommodate pedestrian needs, such as constructing footbridges, marked crosswalks, and barriers separating pedestrians from fast-moving traffic. There is also a pressing need to regulate and monitor public transport vehicles—especially matatus—through improved driver training, route planning, and enforcement of traffic rules.
Targeted public education campaigns focusing on young males can raise awareness about road safety and the dangers of alcohol impairment. Simultaneously, enforcing alcohol control measures and ensuring pedestrian protection in residential and off-street settings will help create safer walking environments. Ultimately, a holistic and sustained approach involving urban planners, law enforcement, transport authorities, and community stakeholders is vital to improve pedestrian safety in Nairobi.
Conflicts of Interest
The author declares no conflicts of interest.