Introduction

Transportation safety has become a key concern for researchers and policymakers worldwide, particularly in low- and middle-income countries where road traffic accidents (RTA) have a disproportionate impact. According to the Global Status Report on Road Safety, 50 million people suffer non-fatal injuries from motor vehicle accidents each year, while 1.19 million people die in traffic-related collisions annually1. Globally, RTA is the leading cause of death for children and young adults aged 5 to 292. If effective measures are not implemented, motor vehicle fatalities are projected to reach two million per year by 2030. To address this growing crisis, road traffic safety has been prioritized in the United Nations’ 2030 Agenda for Sustainable Development, which seeks to significantly reduce traffic-related deaths and injuries3.

In Pakistan, a middle-income country, road traffic accidents cause an alarmingly high number of injuries, with around 25,781 fatalities each year2,4. The country’s fatality rate is 14.3 per 100,000 people, which is slightly lower than the global average of 17.45. However, the large number of motorcycles and motorized three-wheelers (3-WMR) in the country presents a significant challenge to road safety. For example, traffic crashes involving motorcycles result in nearly 50,000 injuries annually, accounting for 60% of all reported accidents6. Driver distraction, speeding, and noncompliance with traffic rules have been identified as some of the key factors contributing to these crashes7,8. Additionally, human attributes (age, gender, driving history), vehicle parameters (production year, engine size), stability and limited protective features9, and roadway and environmental conditions have been found to have various impacts on the severity of motorcycle crashes6,10,11,12,13.

Commercial 3-WMR, commonly known as autorickshaw, tuk-tuk, qing-qi, or Ching-chi, as illustrated in Fig. 1, have become a common means of transportation in Pakistan, notably for short-distance commuting and small-scale products delivery among low- and middle-income communities because of their low costs14. Due to their extensive use, 3-WMRs pose significant safety risks in the often mixed traffic situations that characterize many regions of the country15. These vehicles have low stability, low crashworthiness, and lack standard safety features like airbags and seatbelts. These limitations increase the chance of injuries in collisions16. Furthermore, their drivers often engage in traffic offenses, resulting in further safety issues17. However, their specific safety problems remain underexplored18,19. Beyond their safety concerns, these vehicles contribute significantly to traffic congestion, air pollution, and noise in urban areas20,21.

The motivation behind the research is that there is a limited understanding of the risk variables linked to 3-WMR crashes since studies frequently use out-of-date datasets that do not adequately reflect current traffic circumstances22,23. Furthermore, many studies combine 3-WMRs with other vulnerable road users, including two-wheelers and cycle rickshaws, pedestrians, without taking into account the particular safety risks that these vehicles present to each other19,24.

Despite the prevalence of motorcycles and 3-WMRs in Southeast and South Asian countries, including Pakistan, there has been little research into the interaction of these two vehicle types in crash scenarios. Several studies have examined motorbike safety in these areas, focusing on factors such as risky behavior, fatigue, education level, and road conditions6,8,11,12,13,25,26,27,28,29,30,31,32,33, While few research have addressed the safety of 3 WMRs18,19,22,23,24,34,35,36,37,38. For example,28 reported that younger motorbike riders, those who engage in high-risk behaviours such as speeding and drinking, and those riding at night are more likely to be at fault in crashes in Thailand. A study by31 reported that in Hanoi, Vietnam, 16% of motorcycle taxi drivers were involved in fatigue-related crashes. Being overweight, working full-time, and making more deliveries increased the likelihood of these crashes. A study by27 in Malaysia indicated that poor road surface conditions, high speed restrictions, risky road geometry, and adverse weather considerably increase the chance of severe and fatal injuries to motorbike riders.

A study conducted by29 in Thailand revealed that the severity of motorcyclist injuries increased on weekends and holidays, with factors such as speeding, alcohol consumption, and road conditions strongly influencing injury severity. A study conducted by39 in India observed that the type of collision, number of vehicles, and lane count all have an impact on the severity of a motorbike crash. Single-vehicle crashes were linked to a higher risk of fatality. However, there is a notable gap in research specifically addressing crashes between 3-WMRs and motorbikes. Existing research often groups 3-WMRs and motorcycles into broader vulnerable road user groups or separately. For example a study conducted26 and6 in Rawalpindi, Pakistan, found that motorcycle and 3-WMR collisions increase the risk of minor and severe injuries to motorcycles’ riders. Factors such as the speed limit (70 km/h or higher), roads (lane two and three), the presence of pillion riders, and lower education levels all have an impact on this. While35 and34 found that crashes involving 3-WMR and motorcycles make up 41.06% of all crash types in Rawalpindi, Pakistan. However, their study was limited as it did not account for the direct interaction between 3-WMRs and motorcycles, neglecting their specific operational features and risks when involved in crashes together. preventing a more in-depth knowledge of the topic. Considering that 3-WMRs and motorcycles have similar demand and utility, there are high levels of interaction on the road. These interactions expose them to possible traffic conflicts26. With the lack of hard protective chassis for either of these vehicle types and the low stability, crashes involving these vehicles tend to result in severe injuries. The risks of injury to rickshaw drivers in such collisions remain particularly underexplored. Whereas there is a dearth of literature on 3-WMRs, there is a considerable gap in the safety literature on 3-WMRs collisions with motorcycles.

This is a significant barrier to establishing specific strategies to address the safety issues associated with such crashes. The lack of studies in this area may be due to data availability, quality, and comprehensiveness. This study seeks to fill the gap in this area by exploring the factors associated with the severity of crashes involving 3-WMR and motorcycles in Pakistan. However, most 3-WMR research has utilized simple analytical methodologies, such as binary models and descriptive statistics22,24,40 as illustrated in Table 1. Notably,35 used a correlated random parameters model. To overcome these limitations, this study adopts the widely used and robust injury severity analysis technique, the random parameter multinomial logit (RPMNL) model, the analysis accounts for unobserved heterogeneity in the impact of crash-related factors, such as driver characteristics, environmental conditions, traffic characteristics, and road conditions. The proposed RPMNL approach, unlike conventional fixed-parameter models, allows for a more nuanced understanding of injury severity determinants in 3-WMR and motorcycle collisions.

This study provides a few significant contributions. First, it focusses on collisions between 3-WMRs and motorcycles, a subject that has been overlooked in previous study. Second, it evaluates the injury severity of 3-WMR drivers in these crashes, providing insights into the risks encountered by this vulnerable group. Third, the study uses a robust random parameters multinomial logit model with heterogeneity in means and variance, addressing unobserved heterogeneity in crash data to preserve methodological consistency. Finally, the findings of this study are expected to provide the basis for evidence-based countermeasure development and implementation in Pakistan and other countries across the developing world that may be facing similar challenges with 3-WMR and motorcycles.

The rest of the paper is organized as follows: The next section includes the relevant literature, and a detailed description of the data used in this research. After that, the methodology is thoroughly described, and the findings are displayed. Finally, concluding remarks highlighting the significant discoveries and insights from this research are given, along with policy recommendations to improve the safety of 3-WMRs.

Fig. 1
figure 1

Two types of 3-WMR: ching-chi (left), and autorickshaws (right). Reprinted with permission from Copyright 2024, Elsevier (2024), Ltd35.

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Table 1 Key findings and methodological techniques used in 3-WMR safety research.
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Literature review

Road safety: views from developing countries

Predicting injury severity for each road user group is an important part of road safety research42. The rise in traffic crashes is a worldwide issue, presenting significant threats to public health and socio-economic stability, especially in developing countries13,43. As developing countries account for more than 91% of traffic-related fatalities worldwide44. Although road safety standards in these regions frequently resemble those of the high-income countries, the characteristics of traffic accidents differ significantly35. This disparity foremost results from differing driving attitudes and road conditions, like inadequate pedestrian infrastructure, absence of dedicated lanes for bicycles and powered two-wheelers, and frequent roadside impediments imposed by vendors38,45. These distinctive factors contribute to a safety environment that differs from developed countries, influencing injury severity in distinct ways46.

Pakistan is a middle-income country with a very high rate of road traffic accidents, mostly impacting people with low incomes12,47. Vulnerable road users, such as pedestrians, two-wheeler riders, and public transportation passengers, account for a high number of fatalities12,26,48. Road safety in Pakistan is still insufficient, even though road transportation employs over 6% of the total workforce and contributes over 10% of the country’s gross domestic product (GDP). An estimated 22,000 people die in traffic crashes each year in the country, with two-wheeler motorbikes and three-wheelers (3-WMR) accounting for 60% of the fatalities6,49. The number of recorded crashes has increased since 2015. However, because many non-fatal incidents go unreported, these estimates understate the true scope of the problem. This is substantially higher than the comparable figures in developed countries. For example, in Australia, all VRUs account for 34% of total crashes50. In the United States, although making up only 3% of total vehicle registrations, motorcyclists accounted for 14% of total traffic fatalities in 201051.

Driver distraction, excessive speeding, and breaking traffic laws are the leading causes of crashes in the country7,52. Majority of traffic safety research conducted in Pakistan examines the severity of four-wheeler crashes41,53,54,55,56, pedestrians52,57,58, and motorcyclists6,11,12,25,47,59. However, the safety analysis of a typical modes such as 3-WMR has gotten less attention, leaving a critical gap in the understanding of these unique and widespread vehicles in Pakistan’s traffic landscape.

Previous safety studies focused on 3-WMR

3-WMRs have unique safety challenges when compared to four-wheelers such as cars. While they provide more stability than two-wheelers due to the extra wheel, they are still significantly less stable than four-wheelers. This instability is most apparent during fast turn or when carrying uneven loads, increasing the chance of rollovers60,61. Furthermore, the high center of gravity in 3-WMRs makes them more prone to toppling, especially on uneven ground or sudden turns, increasing the likelihood of severe crashes. Unlike other vehicles such as cars, 3-WMRs lack protective safety features such as a weak protective shell, leaving drivers more vulnerable to severe injury or even ejection in the event of a crash or abrupt braking34. Based on media reports and newspaper articles, the majority of 3 W-MR drivers are unlicensed and have little experience, and they routinely engage in traffic violations such as speeding, overtaking, ignoring one-way laws, traffic signals, and competing for passengers with other drivers62,63,64. As a result, 3-WMR drivers are more exposed and face a higher risk of injury in crashes19.

Despite significant safety concerns, there has been limited study on the safety and risk factors specific to 3-WMRs in the existing literature. For example,23 performed a study to analyze the characteristics and injury patterns in incidents involving 3-WMRs. The findings of their research demonstrated that the likelihood of incurring multiple injuries, particularly those resulting in fatalities, was significantly elevated in frontal or head-on crashes.45 investigated the significant variables that lead to severe injuries in 3-WMR. Their findings linked severe injuries to driver characteristics like young age and aggressive driving, road conditions like three- and four-way intersections, and crash types including right-angle and head-on collisions.65 noted that high traffic volume, inadequate infrastructure, reckless driving, and poor maintenance all contribute to more frequent crashes involving 3-WMRs in in urban areas of India.66 examined the influence of vehicle design on stability of three-wheeled vehicles, showing an increased likelihood of wheel lift-off when such vehicles hit roads barriers at high speeds. likewise they noted that reckless driving, driver age, and a rollover crash were notable risk factors linked to 3-WMR collisions.34 developed a machine learning-based sensitivity framework to identify risk variables for severe and fatal injuries in 3-WMR crashes in Pakistan. Their finding found that speeding, young age, and crash types are significant causes to increased injury severity among 3-WMR occupants.67 noted that 3-WMR are more likely to overturn when trying to avoid obstacles and easy turns.18 investigated the severity of injuries in two- and three-wheeled motorized vehicles. The study revealed irresponsible driving, young age, and rollover crashes as significant risk factors for 3-WMR incidents.68 found that the most injured patients in 3 W-MR crashes were between the ages of 21 and 30. The study concluded that vehicle overturning was the leading cause of injuries.35 developed a correlated random parameter approach to identify risk variables for severe and fatal injuries in 3-WMR crashes in Pakistan. Their study shows that, a few variables, including posted speed limits above 70 km/h, off-peak hours, incidents involving trucks or pedestrians, overturning of the 3-WMR, rainy weather, speeding, weekends, evening, and young drivers, contributed to the severity of injuries in crashes. These findings underscore the need for additional research to understand better and prevent the risks associated with 3-WMR crashes.

Methodological approaches

Injury severity in crash data is generally recorded as a discrete variable, making discrete outcome modeling techniques particularly well-suited for analyzing injury severity see69 for a comprehensive review of crash injury severity models and analytical approaches. In this study, a random parameter multinomial logit model with heterogeneity in means and variances was adopted to examine the factors that are significantly associated with injury outcomes in 3-WMR-motorcycle collisions. The choice of this model addresses unobserved heterogeneity factors not directly measured that vary across individual crash observations70. By accounting for unobserved heterogeneity, the analysis gains greater accuracy, ensuring that the model’s inferences are robust and reflect the true underlying patterns in injury outcomes. For the injury severity analysis, three discrete crash outcome categories are considered in this study: major injury, minor injury, and no injury. An injury severity function \({S}_{in}\) that determines the probability that crash \(n\) will result in injury severity \(i\)71 is defined as:

$${S}_{in}={\beta }_{i}{X}_{in}+{\epsilon }_{in}$$
(1)

Where \({\beta }_{i}\) is a vector of estimable parameter for injury outcome \(i\) (fatal injury, hospitalized injury, minor injury, and no injury), \({X}_{in}\) is a vector of independent variables that affect the likelihood of injury outcome \(C\) in crash\(n\) and \({\epsilon }_{in}\) is the stochastic error term. If \({\epsilon }_{in}\) follows an independent and identically distributed extreme value Type I distribution71, and parameter variations across observations are allowed by introducing a mixing distribution72, the resulting random parameters logit model is expressed as:

$${P}_{n}\left(i\right)=\int \frac{exp\left({\beta }_{i}{X}_{in}\right)}{\varSigma exp\left({\beta }_{i}{X}_{in}\right)}f\left(\beta |\varphi \right)d\beta$$
(2)

Where \(f\left(\beta |\varphi \right)\) is the density of \(\beta\) and \(\varphi\) corresponds to a vector of parameters of the density function (mean and variance), \({P}_{n}\left(i\right)\) is the probability of injury category \(i\) in crash \(n\) conditional on \(f\left(\beta |\varphi \right)\). \(\beta\) now can account for observation-specific variations in the impact of \(X\) on injury severity probabilities, with \(f\left(\beta |\varphi \right)\) used to determine \(\beta\). The random parameter logit probabilities are a weighted average for different values of \(\beta\) across observations where \(\beta\) can either be fixed across observations or vary across observations. Heterogeneity in means and variances of random parameters is accounted for by allowing \({\beta }_{i}\) to vary across crashes as73,74,75.

$${\beta }_{i}= \beta + {{\Theta }}_{i}{Z}_{i}+ {\sigma }_{i}exp\left({\omega }_{i}{W}_{i}\right){\upsilon }_{i}$$
(3)

where \(\beta\) is the mean parameter estimate across all crashes, \({Z}_{i}\) represent the explanatory variables’ vector that captures heterogeneity in the mean with parameter vector \({{\Theta }}_{i}\), and \({W}_{i}\) is a vector of attributes that capture heterogeneity in standard deviation \({\sigma }_{i}\) with corresponding parameter vector \({\omega }_{i}\) and a disturbance term \(\upsilon i\). This model in this study is estimated by simulated maximum likelihood estimation with the logit probabilities shown in Eq. (3) approximated by drawing values of \(\beta\) from \(f\left(\beta |\varphi \right)\) for given values of \(\varphi\), using 1000 Halton draws76. The normal distribution was used for the functional form of the parameter density functions73,74,77. Marginal effects were further computed to investigate the effect of the explanatory variables on the injury-severity outcome probabilities78. In this study, all the explanatory variables are coded as indicator variables. As such, the marginal effects are calculated as:

$${\text{M}\text{E}}_{{\text{X}}_{\text{i}\text{j}\text{k}}}^{{\text{P}}_{\text{i}\text{j}}}={\text{P}}_{\text{i}\text{j}}\left({\text{X}}_{\text{i}\text{j}\text{k}}=1\right)-{\text{P}}_{\text{i}\text{j}}\left({\text{X}}_{\text{i}\text{j}\text{k}}=0\right)$$
(4)

The marginal effect represents the change in probabilities specific to each severity level \(i\) for crash \(j\) when the kth indicator variable, \({ \text{X}}_{\text{i}\text{j}\text{k}},\) takes on a value of 1 or 0 while all other variables remain constant. For variables with random parameters across all observations, only the estimated mean value of the coefficients is used in the injury severity function to calculate the marginal effects. The marginal effect for each parameter is calculated by averaging the marginal effects of overall crash observations. The model was estimated using NLOGIT 6 software.

Data description

The study was conducted in Rawalpindi, a city in northern Pakistan close to Islamabad, the country’s capital. According to the 2017 national census, Rawalpindi, the fourth-largest city in Pakistan, had a population of 2.10 million. Significantly, the city’s 3-WMRs have increased dramatically during the last ten years34. Three years of 3-WMR crash data, spanning January 2019 through December 2021, are used in the study. The RESCUE 1122 department keeps records of crash reports. Data lacking information about key crash attributes, duplicate entries, and outliers were eliminated. The outcomes of the severity of injuries 3-WMR were split into three groups: no injury, minor injury, and major injury.

The outcomes of crashes with no injury were 17.72%, minor injuries 59.63%, and major injuries 22.65%. Table 2 provides the descriptive statistics of the variables implemented for model development. Driver-specific statistics include the age of 3-WMR drivers, with those aged 20–30 contributing a considerable amount (36.27%) to all crashes. Road-specific details include data on posted speed limits, highway classifications, and the number of lanes. Lastly, crash attributes include details on reported causes of crashes (such as speeding, distraction, U-turns, and wrong-way driving) types of crashes 3-WMR hit motorcyclists were considered for the study.

Table 2 Summary statistics for variables available for model Estimation.
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Model estimation results

Table 3 shows the estimated results of injury severity analysis for 3-WMR collisions with motorcycles in Pakistan. The models were estimated to use the maximum likelihood approach with 1000 Halton draws and the random variables were assumed to follow a normal distribution. Discussion of the model results will start with the random variable and then proceed with the remaining variables, grouped together under common themes.

Heterogeneity in mean and variance of random parameters

The indicator variable for “Off-peak” (defined for the no injury severity function) was found to produce random parameter with a mean of − 1.513 and a standard deviation of 3.263. From the normal distribution curve, these numbers indicate that for 32.14% of crashes that occurred during off-peak hours, the probability of no injury is low (meaning some form of injury was likely) and for 67.86% of the crashes that occurred during off-peak hours, the probability of no injury is high. The “daytime” and “cloudy weather condition” indicator variables were found to have statistically significant impacts on the “off-peak” random variable. The “daytime” variable decreased the mean of the random variable, indicating that 3-WRM collisions with motorcycles that occur during off-peak hours were less likely to result in no injury during the daytime. This is consistent with the earlier research34. On the other hand, the “cloudy weather condition” variable increased the mean of the “off-peak” random variable, indicating that crashes that occurred during off-peak hours on a cloudy day were more likely to result in no injury. With regards to heterogeneity in variance of the random variable, the “winter” indicator variable was found to have significant impact on the “off-peak” random variable. The positive effect of the winter indicator variable on the variance of the “off-peak” variable indicates that the collisions that occur during off-peak hours during winter months were more likely to result in no injury. The marginal effects of the “off-peak” variable show that the probability of recording injury, either major or minor, was lower and the likelihood of no injury was higher. This means that the chances of off-peak hour collisions between 3-WMRs and motorcycles resulting in any form of injury are generally low.

Roadway characteristics

Two roadway features were found to affect injury outcomes significantly in this study, as shown in Table 3. The two-lane road variable decreased the probability of major injury by 0.0322 but increased the probability of minor injury by 0.0268 and no injury by 0.0054. The findings are consistent with earlier studies, which indicate that crashes on local roads are more likely to result in minor injuries6,8,79. The explanation might be that local roads usually have fewer lanes and slower speeds, which reduce the risk of severe or fatal injuries and increase the likelihood of minor injuries. Similarly, the speed limit indicator variable for 70 km/h or more also decreased the probability of major injury but increased the likelihood of minor injury and no injury severity outcomes, as was also observed by35. The reduction in major injuries among 3-WMR drivers after crashes with motorcyclists may be attributed to many factors. As motorcycles differ from other vehicles in terms of physical design (lower size, two wheel base) and driver exposure80. The 3-WMR gives more stability due to the additional wheel and better structural protection due to their enclosed metal frames than two-wheel motorbikes60,61. In collisions, the rickshaw’s weight absorbs more impact energy, hence decreasing the severity of injuries to the driver.

Driver attributes

With regards to the 3-WMR driver’s characteristics, age, and gender were found to significantly influence the injury outcomes of collisions with motorcycles. Collisions involving teen drivers, those between 30 and 40 years of age and those between 40 and 50 years of age, were found to have a lower probability of recording major injuries but have a higher probability of resulting in minor injuries. This trend may be linked to the 3-WMRs, which are generally more stable because of their design, which incorporates a lower center of gravity and a larger wheelbase81. This structural benefit reduces the chance of rolling, especially while making abrupt turns or maneuvers81, which may help to reduce the probability of major injuries. Where the driver was a female, the probability of the crash leading to major injuries increased by 0.0301 and the likelihood of minor injuries is reduced by 0.0370. This is in line with earlier studies that found female drivers are more likely than male drivers to have disability, maybe as a result of inexperience or a distinct combination of risk factors82,83. This trend could be related to various factors, including possible disparities in experience and training, as female drivers may be less experienced with operating these vehicles. Furthermore, societal pressures may contribute to riskier driving practices, with women possibly considered as more vulnerable road users, which may influence their injury outcomes.

Temporal characteristics

From the model estimation results, crashes that occurred during weekends were less likely to result in major injuries but more likely to lead to minor injuries and no injuries. This might be because there is less traffic on weekends, which decreases the possibility of collisions. Due to the time off, many professionals who usually ride motorcycles, such as bankers, teachers, and students, spend the weekend at home, and this lowers the number of motorcycles on the road. These factors combine to shift injury severity trends during weekend collisions. However, some previous studies indicated that injuries are more severe on weekends, which is frequently associated with higher alcohol intake84,85. However, in Pakistan, where cultural norms strictly prohibit alcohol usage, this feature is less relevant.

Similarly, the “Autumn” indicator variables also decrease the probability of major injuries but increase the probability of minor and no injury outcomes by 0.0081 and 0.0016, respectively. This is consistent with previous findings86. The explanation could be due to seasonal changes in weather conditions, which could result in more cautious driving practices. Autumn usually brings milder temperatures and clear skies, making travel safer. Furthermore, road conditions may be less hazardous than during winter seasons, minimizing the severity of crashes. These factors contribute to an increased risk of minor injuries rather than severe outcomes across the autumn.

Similarly, the AM indicator reveals that the likelihood of a 3-WMR rider suffering a major injury, or no injury decreases by 0.0123 and 0.0043, respectively. Meanwhile, the probability of minor injury rises by 0.0166 when accidents occur in the AM hours, particularly between 7:00 and 9:00 AM. The decline in major and no injuries during AM hours could be ascribed to variables such as better visibility and safer driving approaches, as riders are often more careful at the start of their day. Furthermore, the increased traffic density associated with morning commuting patterns adds to more frequent low-speed collisions87. These low-speed impacts are less likely to result in major and no injuries, but may cause minor injuries, especially for rickshaw drivers. The careful behavior of most drivers in the morning, along with the protective design of rickshaws, further minimizes the likelihood of major injuries while leaving drivers vulnerable to minor injuries and scratches. However, the increase in minor injuries could be related to more aggressive riding habits, such as speeding, as some riders race to work or school6. This combination of factors highlights the interaction of temporal, behavioral, and traffic dynamics to influence injury outcomes.

Environmental characteristics

Two environment-related factors were found to have a significant association with injury outcomes. The results show that 3-WMR crashes in sunny conditions are much less likely to major and minor injuries to rickshaw drivers. This finding is consistent with past studies8,56,88. This may be because in sunny weather, better visibility allows drivers to anticipate and respond more effectively. Dry road conditions make it possible to improve traction and vehicle control, reducing the chance of sliding and severe impacts. Sunny weather stimulates smoother traffic flow and encourages less stressful driving behaviors. Further, 3-WMR protective design, which includes partial enclosures, helps shield drivers during low-energy crashes, contributing to lower injury severity. rain indicator variable was found to decrease the probability of major injury by 0.0117. However, the rain variable increased the probability of minor and no injuries outcome. The explanation might be that decrease in major injuries of rickshaw drivers during rainy weather can be attributed to drivers slowing their speed to compensate for poor visibility and reduced traction on wet roads. Lower speeds provide less kinetic energy during crashes, lowering the risk of major injury. Conversely, the increase in no and minor injuries could be attributed to more low-impact crashes due to decreasing tire-road friction, which makes it more difficult for drivers to control their vehicles on slippery surfaces. These findings are consistent with previous studies6,10,11,12.

Crash characteristics

Multiple crash contributing factors were tested to understand how they are significantly associated with crash outcomes. Three of these variables came out to be significant. The “wrong turn”, “speed”, and “distracted” indicator variables all increase the probability of major injury. The wrong turn variable increased the probability of major injury by 0.011. which is consistent with past research12. The explanation could be attributed to the quick nature of U-turns, combined with limited vision and reaction time in such situations, which frequently result in unexpected and severe crashes. Similarly, a wrong turn entails frequent directional shifts and higher speeds, which can increase the severity of crashes. The instability of 3-WMRs increases the risk, as even small errors in judgement can result in a loss of control and an increased probability of major crashes.

The speed variable increased the probability of major injuries by 0.0371. Over speeding crashes had a significant positive link with major and minor injury outcomes, as shown in Table 3. This could be because over speeding raises the kinetic energy in high impact crashes and the human body is limited in the amount of energy it can safely absorb. Compared to four-wheeled vehicles, 3-WMRs have a partial and comparatively weaker body design, increasing the likelihood of major injuries for riders in high-impact crashes. Furthermore, the limited stability of 3-WMRs may exacerbate the effects of excessive speeding, making it more difficult for drivers to maintain control of the vehicle in emergency situations or during abrupt stops19. These results align with the findings of earlier research17,34.

Also, the distracted driving variable increased the likelihood of major injury by 0.0040. The marginal effects further revealed that the wrong turn variable decreased the likelihood of minor injuries while the speed and distracted driving variables increased the likelihood minor injuries. Previous studies7,52 have made similar observations.

Discussion on risk factors and safety interventions in developing countries

Several recent studies have examined the role of potential crash risk factors in influencing the severity of crashes between 3-WMR and motorcycles. To decrease the severity of injuries and fatalities, various safety interventions and policy recommendations have been presented. The results of this study, which indicate key risk factors such as speeding, distracted driving, and wrong turn, align with the findings of previous studies6,13,16,19,25,28,29,30,31,32,35,89,90.

Likewise, insufficient law enforcement and unregulated movement of motorbikes and 3-WMR have been highlighted as prominent risk indicators in developing countries. Similarly, earlier research has shown that the lack of lane discipline, mixed traffic conditions, and poor street lighting contribute to increased injury severity risks to motorcycles and 3-WMR riders13,34,90. Failing to obtain a valid driver’s license and a lack of sufficient training are also among the leading risk factors in these collisions. Similarly, the absence of mandatory helmet use in some countries, along with the failure to wear helmets, is another, key risk factor that increases the severity of injuries in motorcycle and 3-WMR crashes25.

To mitigate such infrastructural deficiencies and poor regulatory frameworks, various effective safety interventions and policy rules have been suggested and implemented with substantial success to address the safety concerns of motorcycle and 3-WMR in developing countries. Studies conducted in developing countries highlighted that frequency and severity of motorcycles and 3-WMR have significantly decreased because of several safety initiatives like as dedicated lane marking and use, compliance with required helmet use, and speed enforcement programs. For instance, improved enforcement of mandatory helmet regulations and speed restrictions, as well as the use of automated speed enforcement programs, has been demonstrated to drastically reduce motorcycle-related fatalities and crashes91,92. In country like Indonesia, the introduction of these measures has resulted in significant decreases in severe and fatal injuries93,94.

The economic feasibility of safety initiatives is vital, especially in countries with limited road safety budgets. The implementation of mandatory helmet laws, for example, has shown a beneficial cost-benefit ratio ranging from 1.33 to 5.07, as they reduce fatal injuries and medical costs. Mandatory helmet regulations in Taiwan, Thailand, and Malaysia have resulted in considerable decreases in fatalities and injuries. For example, Thailand saw a 41.4% drop in head injuries after implementing helmet laws92.

Despite the proven success of these interventions, implementing them in developing countries presents substantial challenges including financial constraints, socio-cultural impediments, and institutional limitations. For example, poorly implemented helmet laws, driven by a lack of police competence and corruption, undermine their effectiveness. Cultural beliefs and discomfort surrounding safety gear also provide obstacles. Further, the expensive cost of decent helmets and safety gear makes it impossible for low-income riders to comply.

Infrastructure challenges, such as the lack of separate motorcyclists and 3-WMR lanes and poorly built roadways, significantly increases crash risks. To address these limitations, solutions like automated enforcement systems (AES) may reduce the reliance on manual police. Financial incentives such as government subsidies or tax rebates can help make safety gear more affordable, while substantial public awareness campaigns can contribute to cultural attitudes towards safety. Improved urban planning and road design, particularly the introduction of designated lanes for motorbikes and 3-WMR, can also contribute to safer road environments.

Successful case studies in countries with similar issues have shown that a combination of severe enforcement, public education, financial incentives, and thorough training may improve the safety of vulnerable road users (VRUs) in limited in resources environments95.

Table 3 Model estimation results for injury severity analysis of 3-WMR collisions with motorcycles.
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Policy implications

The findings of this study present several vital policy recommendations aimed at improving the safety of 3-WMRs engaged in crashes with motorcycles. These recommendations are applicable not only to Pakistan, but also to other developing countries dealing with similar road safety concerns.

First, the study identified speeding as a key contributor to crash severity. To address this, automated speed enforcement systems should be installed, complete with real-time violation tracking. These devices, along with increased penalties for speed offences, would discourage speeding and improve road safety for 3-WMRs drivers. Recent study demonstrates that automated speed cameras significantly reduce vehicle speeds and traffic offences, emphasizing their effectiveness in enhancing road safety96. Second, distracted driving has been identified as a key contributor to major injury in 3WMR crashes. To mitigate this, public awareness efforts should be established to educate drivers on the dangers of distractions, using cell phones while driving. These programs should highlight the need of maintaining focus and encourage safer driving behaviours. Studies show that educational interventions can reduce distracted driving behaviours97. Third, the study revealed that wrong turns are one of the main causes of major injuries in 3-WMR crashes. To reduce these crashes, high-risk junctions should have clear signs and designated turning lanes. Increasing traffic police patrols in these areas will also improve enforcement of turning laws, prevent violations, and reduce crashes. Studies suggest that increasing traffic police patrols in high-crashed areas improves enforcement, resulting to a reduction in violations and crashes98.

A comparative review of successful safety measures in other developing countries, such as India, Indonesia, and Taiwan, indicates effective strategies that might be implemented in Pakistan. In Pakistan, helmets are now only required for motorcycle riders. However, no special helmet rules exist for 3-WMR drivers34. The use of helmets among 3-WMR drivers should be legislated and strictly enforced on immediate priority to reduce the burden of such crashes. For example, the implementation of mandatory helmet rules for all motorcycle riders in India has considerably lowered crash rates and injury severity91. This strategy could be adopted by mandating helmet use for 3-WMR drivers, likewise, Indonesia and Malaysia implementation of dedicated lanes for motorbikes has successfully reduced the number of collisions involving motorcycles and other vehicles99,100. A similar approach might be implemented in risky areas to separate 3-WMR from motorcycles and other vehicles, thus reducing direct contact and lowering the likelihood of crashes. Driver education and training programs for 3-WMR drivers should be introduced to improve road safety. These programs should concentrate on helmet use, vehicle maintenance, safe speeds, and attention to traffic laws, such as observing traffic signals and relinquishing to pedestrians. Training should also cover dealing with high-risk situations, like driving in bad weather, at night, or in heavy traffic. Taiwan’s Road Safety Class (RSC), which includes motorcycle safety training, was made mandatory for freshman motorcyclists in 2013. The program combines safety lectures with accidents videos to reduce violations and crashes95. This strategy could be adopted for 3-WMR drivers in Pakistan and other developing countries.

In addition to developing country strategies, studying successful interventions in developed countries might provide significant insights. For instance, Sweden, Italy, and Spain have included advanced safety technologies, such as anti-lock brake systems (ABS), into their motorcycle designs. In Japan, seat belts are required for all vehicle occupants, but motorcyclists must wear helmets to reduce the risk of injury or death in crashes101. These features have been shown to be extremely successful at preventing collisions and reducing injury severity. Manufacturers should also incorporate other advanced safety features, such as electronic stability control and proximity sensors, into vehicle design to prevent crashes.

The authors recommend introducing these features in 3-WMRs in developing countries, such as Pakistan. Though the initial cost of such technology may be substantial, the long-term benefits, including reduced medical expenses and fatalities, justify the investment.

The findings from this study can be efficiently adapted to various cultural and infrastructural contexts. In developing countries, where infrastructure may be inadequate, the study’s recommendations can be phased in gradually. For example, while helmet use is critical to reducing head injuries, cultural differences may influence its adoption. In some regions, helmets may not be widely worn due to factors such as comfort, fashion, or cost. However, with proper education, community involvement, and tailored messaging, it is possible to shift attitudes and increase helmet use. In areas with inadequate road markings or traffic signals, clear signage and dedicated lanes might be implemented in high-risk zones. Through community engagement and safety measures adapting to local demands, these findings can enhance road safety for 3-WMR drivers across diverse regions. Implementing these recommendations will necessitate a concerted effort across various stakeholders, including vehicle manufacturers, traffic enforcement agencies, road safety specialists, and researchers. Such an integrated approach would ensure that these safety measures are implemented successfully, improving overall road safety and lowering the risk of injuries in 3-WMR and motorcycle collisions.

Conclusions

In Pakistan, motorcycles and three-wheel motorcycles have long served as essential modes of transportation, especially for meeting basic mobility needs. Given their widespread use and shared roadways, interactions between motorcycles and 3-WMRs frequently lead to traffic incidents. This study focused on analyzing crash injury severity for collisions involving these vehicles within Rawalpindi, Pakistan, with the goal of uncovering critical factors that influence injury outcomes. To achieve this, three years of 3-WMR crash data, spanning from January 2019 to December 2021, were examined. The study applied a random parameters multinomial logit model with heterogeneity in means and variances to address unobserved heterogeneity and account for unobserved factors that might vary across crashes.

The study’s findings reveal that a range of factors such as roadway conditions, environmental conditions, driver demographics, time of day, season, and crash-specific behaviors significantly impact the severity of injuries sustained. For example, speeding and distracted driving notably increased the likelihood of both minor and major injuries, highlighting the danger these behaviors pose. Risky maneuvers like U-turns show a more nuanced effect; while they increase the probability of severe injuries, they appear to reduce the chance of minor injuries, possibly due to the higher likelihood of high-impact collisions resulting from such turns. The study also noted gender-related differences in crash outcomes; crashes involving female rickshaw drivers were more prone to lead to severe injuries, underscoring a potential need for focused safety interventions.

The insights from this study can inform policy recommendations aimed at reducing injury severity in collisions involving motorcycles and 3-WMRs. First, it is crucial to implement regulatory policies addressing the risks associated with powered two- and three-wheel vehicles. Creating targeted training programs, raising awareness of road safety practices, and improving driver education on risky behaviors like speeding and distracted driving are essential steps toward safer interactions. Furthermore, the implementation of rigorous traffic law enforcement is recommended to ensure compliance with road safety regulations, particularly for speeding and unsafe maneuvering practices.

Additionally, infrastructural modifications could help mitigate risks associated with 3-WMR and motorcycle crashes. For instance, designated lanes for two- and three-wheeled vehicles, enhanced signage, and well-marked zones for safe U-turns can reduce high-risk interactions. Collaboration with community organizations and educational institutions to foster a culture of road safety awareness would also reinforce compliance and promote safer driving habits. Overall, the findings provide a foundation for crafting and enacting countermeasures that could effectively reduce the severity of injuries in these specific types of crashes, improving roadway safety for all users in urban areas like Rawalpindi.

This study offers significant insights through the analysis of a limited data set to investigate factors influencing crashes involving three-wheelers and motorcyclists. This study has some limitations that suggest areas for further investigation. First, the analysis is based on crash data from a particular area, which may limit the applicability of the findings to other places with different traffic conditions or socioeconomic characteristics. Expanding the study to include data from multiple regions or countries may provide deeper insights. Second, while the study focusses on rickshaw drivers’ injuries, it does not consider the injuries sustained by motorcyclists’ drivers involved in these collisions. Future study may explore these other perspectives to provide a more comprehensive view of collision impacts. Third, the random parameters multinomial logit model account for unobserved heterogeneity. There may be unmeasured variables, such as driver fatigue or vehicle conditions, that could further refine the analysis. Incorporating these variables into future studies, either through enhanced data collecting or advanced modelling techniques, might strengthen the findings.