Commercial Bus Research Articles

Aerodynamic evaluation of a commercial bus structure

Abstract This article focuses on the aerodynamics evaluation of a commercial intercity bus used on the highway. The research begins with a brief introduction to the state-of-the-art vehicle aerodynamic assessment using the iterative CFD (computational fluid dynamics) method. The second part presented the method to generate the basic CAD model of a commercial bus using the blueprint images. The boundary conditions and the discretization of computational volume are presented in the third part of this document. The aerodynamic evaluation is performed at a velocity of 33.34 m/s, highlighting the velocity distribution around the bus structure and the air pressure on the bus and road surface. For high accuracy of the simulation results, a movable road surface and a rotation zone is introduced around the wheels, according to the simulation case. After analysing the results of the original model is proposed a geometrical improvement by adding the air deflectors to the bus model. The improved bus model is simulated under the same boundary conditions as the base model. The last part of the document presents the comparison study and its conclusions.

Optimisation of commercial bus body frame based on the improved grey wolf and Monte Carlo simulation algorithm

Optimisation of commercial bus body frame based on the improved grey wolf and Monte Carlo simulation algorithm

Optimisation of commercial bus body frame based on the improved grey wolf and Monte Carlo simulation algorithm

Optimisation of commercial bus body frame based on the improved grey wolf and Monte Carlo simulation algorithm

Hypertension: risk perception and health seeking behaviour of long-distance drivers in Port Harcourt.

Driving as an occupation is associated with the occurrence of heart-related diseases such as hypertension. To assess the perception of modifiable risk factors of hypertension and the health seeking behaviour of long-distance commercial bus drivers in Port Harcourt Metropolis. A cross-sectional study design was used to obtain data from 272 long distance commercial drivers. Data were analysed descriptively using SPSS version 24.0. (p≤0.05). A total of 272 questionnaires were completed and returned (100%). Respondents' mean age was 43.4 ± 8.9. In scoring for perception of modifiable risk factors of hypertension among the drivers, (45.6%) respondents had a high perception score while 148 (54.4%) respondents had a low perception score. In assessing for health seeking behaviour, 190 (69.9%) had checked their blood pressure at least once in their lifetime, 80 (42.1%) of those who had checked, did so over a year ago. However, 18 (9.5%) respondents were on medication for hypertension in the last one month. This study showed that a greater number of the drivers had a low perception of modifiable risk factors of hypertension. Regular health checks were also not observed among participants. There is need for targeted health education for this group.

Energy forecasting with robust, flexible, and explainable machine learning algorithms

AbstractEnergy forecasting is crucial in scheduling and planning future electric load, so as to improve the reliability and safeness of the power grid. Despite recent developments of forecasting algorithms in the machine learning community, there is a lack of general and advanced algorithms specifically considering requirements from the power industry perspective. In this paper, we present eForecaster, a unified AI platform including robust, flexible, and explainable machine learning algorithms for diversified energy forecasting applications. Since October 2021, multiple commercial bus load, system load, and renewable energy forecasting systems built upon eForecaster have been deployed in seven provinces of China. The deployed systems consistently reduce the average Mean Absolute Error (MAE) by 39.8% to 77.0%, with reduced manual work and explainable guidance. In particular, eForecaster also integrates multiple interpretation methods to uncover the working mechanism of the predictive models, which significantly improves forecasts adoption and user satisfaction.

Predicting Fatigue-Associated Aberrant Driving Behaviors Using a Dynamic Weighted Moving Average Model With a Long Short-Term Memory Network Based on Heart Rate Variability.

This study proposed a moving average (MA) approach to dynamically process heart rate variability (HRV) and developed aberrant driving behavior (ADB) prediction models by using long short-term memory (LSTM) networks. Fatigue-associated ADBs have traffic safety implications. Numerous models to predict such acts based on physiological responses have been developed but are still in embryonic stages. This study recorded the data of 20 commercial bus drivers during their routine tasks on four consecutive days and subsequently asked them to complete questionnaires, including subjective sleep quality, driver behavior questionnaire and the Karolinska Sleepiness Scale. Driving behaviors and corresponding HRV were determined using a navigational mobile application and a wristwatch. The dynamic-weighted MA (DWMA) and exponential-weighted MA were used to process HRV in 5-min intervals. The data were independently separated for training and testing. Models were trained with 10-fold cross-validation strategy, their accuracies were evaluated, and Shapley additive explanation (SHAP) values were used to determine feature importance. Significant increases in the standard deviation of NN intervals (SDNN), root mean square of successive heartbeat interval differences (RMSSD), and normalized spectrum of high frequency (nHF) were observed in the pre-event stage. The DWMA-based model exhibited the highest accuracy for both driver types (urban: 84.41%; highway: 80.56%). The SDNN, RMSSD, and nHF demonstrated relatively high SHAP values. HRV metrics can serve as indicators of mental fatigue. DWMA-based LSTM could predict the occurrence of the level of fatigue associated with ADBs. The established models can be used in realistic driving scenarios.

Experiment and performance evaluation of an integrated low-temperature proton exchange membrane fuel cell system with an absorption chiller

When the typical operation temperature of the Proton Exchange Membrane Fuel Cell (PEMFC) reaches 333.15–363.15 K, the ratio of electrical energy to waste heat generated by the PEMFC is about 1. In this paper, an absorption chiller with LiBr/[BMIM]Cl/CH3OH as the working pair is proposed to convert the waste heat into cooling capacity. The PEMFC and absorption chiller (AC) systems have been studied from the energy and efficiency point of view. The COP of the integrated system can reach a maximum of 0.85, which is remarkably 0.35 higher than that of the individual PEMFCs. The electrochemical process of the PEMFC and the thermodynamic process of the AC systems are calculated using MATLAB. The results show that the PEMFC operation temperature of 353.15–358.15K is sufficient to drive the AC and meet the requirement of 273.15–283.15K evaporation temperature and 308.15–313.15K condensation temperature. Meanwhile, when the electric power output from the PEMFC is 100 kW, the AC can output approximately 60 kW cooling capacity, which is sufficient to meet the cooling demand of the commercial bus.

Seat belt usage in buses – An observation study of usage and travellers’ perspectives

This study aims to evaluate seat belt usage in buses and to understand travellers’ incentives of seat belt usage. Methods used are observational studies (10 cities, with 328 bus observations), focus group discussion (7 groups with a total of 32 participants) and a web survey (n = 1737 respondents). The results show that the seat belt use among bus passengers can be improved especially in regional and commercial bus traffic. It is more common to buckle up on long trips than on short trips. However, even though observations show high usage during long trips, travellers report that they remove the seat belt after a while if they want to sleep or for comfort reasons. For the bus drivers it is not possible to control passengers’ usage. Dirty seat belts and technical malfunction might deter some passengers from using them and therefore systematic cleaning and control of seats and belts are recommended. On short trips one reason for not using the belt is related to worries about getting stuck and not being ready to get off in time. In general, it is most important to increase the usage on high-speed roads (>60 km/h), in lower speed it might be more important to provide a seat for each passenger. Based on the results a list of recommendations is presented.

Effects of rate of use of aphrodisiac drinks on some health parameters of commercial bus drivers in Ife-Central local government and inadequacy of information on the packs of many sampled aphrodisiac drinks

Effects of rate of use of aphrodisiac drinks on some health parameters of commercial bus drivers in Ife-Central local government and inadequacy of information on the packs of many sampled aphrodisiac drinks

Psychoactive substance abuse among commercial bus drivers in Umuahia, Abia State, South-Eastern Nigeria: an uncontrolled “epidemic” with attendant road traffic crashes

Background informationThe unprecedented depletion of the productive workforce has been majorly attributed to road traffic crashes (RTCs). The attendant consequences of this depletion have been found to constitute a serious global public health challenge, with the use of psychoactive substances among drivers implicated in every three of five motor vehicle accidents. Hence, this study assessed the pattern and explored the determinants of substance abuse among commercial bus drivers in Umuahia, Abia State.MethodsA descriptive cross-sectional design was used for the study. Four hundred commercial bus drivers were recruited from selected motor parks in Abia-state, using a multistage sampling technique from October to December 2020. A pretested, interviewer-administered questionnaire was administered to obtain socio-demographics and information on substance abuse. Data were analyzed using IBM SPSS version 25; bivariate analysis was done using Chi-square. The level of significance was at 5%.ResultsThe mean age of the respondents was 40.03 ± 10.50 years. The proportion of respondents who had ever abused a psychoactive substance was 74.6%. The most commonly abused substances among drivers include alcohol (51%), cigarettes (27%), and alcoholic herbal mixtures (16%). The study participants had poor knowledge (54.5%) and poor perception (63.2%) about psychoactive substance abuse. Among the factors found to be significantly associated with substance abuse among respondents were ethnicity (p = 0.002), religion (p = 0.009) and monthly income (p = 0.013) of the respondents, poor knowledge (p < 0.001) and poor perception (p < 0.001). However, this study found religion (p = 0.031; OR = 5.469; CI = 1.170 to 25.555), knowledge (p < 0.001; OR = 4.21; CI = 2.201 to 8.287) and perception (p < 0.001; OR = 9.828; CI = 15.572 to 65.052) as factors that were associated with the higher likelihood of psychoactive substance abuse.ConclusionReligion, poor knowledge and perception were associated with the higher likelihood of psychoactive substance abuse among commercial bus drivers. Targeting commercial bus drivers for educational interventions and using religious leaders as conveyor belts may reduce the use of psychoactive substances among them.

Assessment of bus speed influencing factors through the exploitation of machine learning techniques

Bus commercial speed is among the most influencing parameters of public transport quality of service. Literature has highlighted many different factors that affect bus speed in different ways. This paper focuses on the development of predictive models for the estimation of bus commercial speed, as well as on the determination of the effect of several variables on bus speed between successive stops. For the need of predicting bus commercial speed, three (3) machine learning models were developed; a Support Vector Regression (SVR); a Random Forest Regression (RFR); and an Artificial Neural Network (ANN). The models were based on data referring to 10 lines of the bus network of Thessaloniki, Greece. Data included several features such as bus dwell time, passenger demand, bus stop location, bus stop infrastructure etc. Results indicate a satisfactory performance by all models, while the best accuracy was achieved from the ANN model. Afterwards, the analysis focused on the determination of the effect of the explanatory variables on commercial bus speed. To achieve that, the Shapley Additive Explanations (SHAP) algorithm was applied, based on the ANN model. Bus stop spacing was identified as the most contributing feature to the model's output; distance of more than 450 meters between 2 successive stops was found to have a positive effect on bus speed. Single-shelter bus stops were associated with higher bus commercial speed, while the location of bus stops in the middle of a building block proved to affect bus speed in a positive way. Dwell time was also a crucial parameter, having a decreasing effect on bus speed, as its value increases. Additionally, it was found that an increase in the number of traffic lights and turns along a route section, affects bus speed negatively. Finally, no apparent relation was observed between total passenger traffic and bus speed.

Using GIS to Understand Cervical Cancer Screening Behaviors among Women Living with HIV (WLWH) in Ghana

Objective: This study used the Geographic Intelligent Systems to examine the location of cervical cancer screening (CCS) facilities and their proximity to the residential location of Women Living with HIV (WLWH) and how they could influence WLWH CCS behaviors. Methods: We used deidentified existing data from Komfo Anokye Teaching Hospital (KATH) on WLWH and geocoded them to their community of residence as points using Google Earth Pro version 7.3.0. Transport fares from KATH to communities identified in the screening database were also obtained. The location of KATH was digitized from google earth and validated from the GIS database from the Remote Sensing and GIS application Laboratory, University of Ghana. We calculated distances and other proximity information between each point from the KATH. We used the spatial-analytical tool of kernel density for the density analysis and fitted a smoothly tapered surface using Esri’s ArcGIS Desktop 10.8. We performed Shapiro-Wilk normal distribution test to assess the significance of the clustering. Results: Data on 708 WLWH’s residential locations and transportation fares were analyzed. We find a significant clustering near KATH. Close to 50% cluster within 5km from KATH whiles 85.8% of the respondents live within 10.2 km from KATH. Shapiro-Wilk normality test shows W=0.30221, p-value &lt; 0.05. The minimum cost per commercial transportation is approximately GHC 2.00 (US dollar ~ $0.26 whiles those living beyond 3-5 km will pay approximately GHC 3.00 (~$0.39). The highest cost payable by the farthest distance using a commercial bus is GHC 50.00. (~$ 6.00). The majority of respondents will pay about GHC 10.00 (~$1.50) for transportation (i.e., round trip) to access SCC facilities. Conclusions: In an economy where a family lives on less than $2.00 per day, any additional cost resulting from transportation will likely create CCS hesitancy and that self-sampling may be a recommended solution.

Drag reduction of a commercial bus with add-on aerodynamic devices

In the automotive industry, the implementation of drag reduction systems has provided considerable decreases in fuel consumption. These outcomes are in line with the increasing demands of the environmental regulations and consumers’ requirements. Although some studies explain how aerodynamic devices reduce the aerodynamic drag on light and heavy vehicles such as Ahmed bodies and trucks, buses have received almost no attention. For this reason, the flow over the Marcopolo Paradiso 1200 G7 commercial bus and the influence of several aerodynamic devices on the drag force and fuel consumption of the bus are discussed in this article. Three distinct devices (vortex generators, lateral devices, and rails) were proposed after flow visualization tests on the baseline bus. Thus, the entire evaluation consisted of 11 arrangements by combining the three aerodynamic devices. The changes in drag due to all arrangements are estimated using wind tunnel tests, which are validated using Computational Fluid Dynamics simulations. The fuel consumption is evaluated in a simplified long-haul driving cycle between two cities. The devices were able to alter the flow behavior on the bus, resulting in a maximum decrease of 8.63% in the drag coefficient and 3.92% in fuel consumption. Given that the devices used are just first prototypes, we estimate that greater reductions can be achieved with optimized systems. Likewise, this paper probably leads to real applications in other commercial buses due to the evident drag reductions.

Augmentation of crashworthiness design of circular tubular structures by engraving grooves of varying depths

The use of gradiently grooved tubes has reaped emphasis in designing of crashworthiness systems for safeguard of commuters in passenger bus collisions. Also it is very essential to improve the performances of energy absorption systems of gradiently grooved profiles. The tubular structures exhibit superior energy absorption characteristics when subjected to uni-axial loading, on contrary it is highly susceptible to global bending mode when subjected to oblique loading pattern. This work proposes a novel design to enhance the crashworthiness metrics of circular tubular structures subjected to both direct and oblique loading by the engraving of grooves in circumferential direction with varying depths. The structure with varying groove configurations has undergone quasi-static and finite element simulations. The effect of friction contact interaction between the striker and the structure and critical loading angle (θ = 0˚ to 30˚) between them on energy absorption had been explored. The outcome reveals the merits of utilizing gradiently grooved tubes with varying groove depths which may be decreased from the striker end to the stationary end over the original, uniform and gradiently grooved structures subjected to direct and oblique loading patterns. The outcome of the work facilitates designer to enhance the energy absorbing performances for different loading conditions. Lastly, the designed tubular structure as crash buffer befitted in commercial automotive bus application is considered and demonstrated successfully.

Evaluation of In-Vehicle Pollutants Exposure and Respiratory Symptoms among Bus Drivers in Kota Bahru, Malaysia

Abstract Exposure to in-vehicle air pollutants has been recognized as a risk factor for respiratory diseases. The present study, therefore, investigates the factors, including duration of employment and in-vehicle concentrations of fine particulate matter (PM2.5), carbon dioxide (CO2) and nitrogen dioxide (NO2) that can influence the prevalence of respiratory symptoms in commercial bus drivers. A total of 34 bus drivers and 51 administrative staff (comparative group) from the bus operator in Kota Bahru, Malaysia were randomly enrolled in this cross-sectional study. The personal characteristics and respiratory symptoms were reported using a validated questionnaire from the American Thoracic Society (ATS-DLD-78-A). In-vehicle concentrations of PM2.5, CO2 and NO2 were continuously measured over eight hours on each bus driver. The prevalence of self-reported cough, phlegm and chronic phlegm among bus drivers were 55.9%, 73.5% and 35.3%, respectively, significantly higher compared to the comparative group (p &lt; 0.001). Moreover, the duration of employment with bus operators for more than four years was significantly related to the manifestation of phlegm (OR = 8.27, 95% CI = 3.12-21.89) and cough (OR = 4.57, 95% CI = 1.66-12.59). Among the pollutants measured, concentrations of PM2.5 (92.1 µg/m3) and CO2 (286.9 ppm) inside the buses were significantly higher in the morning compared to afternoon hours (p &lt; 0.001). These findings provide important evidence for further surveillance programs that could reduce occupational exposure for bus drivers.

ELECTRIC ROAD – A REVIEW

An electric road, eroad, or electric road system (ERS) is a road which supplies electric power to vehicles travelling on it. Common implementations are overhead power lines above the road and ground-level power supply through conductive rails or inductive coils embedded in the road. Overhead power lines are limited to commercial vehicles while ground-level power can be used by any vehicle, which allows for public charging through power metering and billing systems. 10–11 Korea was the first to implement a public electric road with a commercial bus line in 2013 after testing an experimental shuttle service in 2009. Sweden has been performing assessments of various electric road technologies. since 2013 and expects to start formulating a national electric road system in 2022 and finish planning by2033 Furthermore, the technology is more expensive, as inductive charging requires drive electronics and coils in both device and charger, thus, it increases the complexity and cost of manufacturing.

Risk of obstructive sleep apnea and traffic accidents among male bus drivers in Ecuador: Is there a significant relationship?

BackgroundObstructive sleep apnea (OSA) represents an important occupational health concern in the transportation industry, affecting a substantial percentage of transportation operators. Our study aims to determine the frequency of individuals at high risk of obstructive sleep apnea, and excessive daytime sleepiness, as well as any potential association between these conditions and traffic accidents among a sample of Ecuadorian bus drivers. MethodsWe conducted a cross-sectional study involving 340 commercial bus drivers from Ecuador. Descriptive statistics were used to determine frequency and proportions for demographic and clinical variables. A Kendall's tau-b was performed to ascertain the relationship between the STOP-Bang score towards the Epworth Sleepiness Scale (ESS) score and the number of accidents and near accidents. ResultsIn general, 18.5% (n = 63) of participants were found to be at high-risk for OSA. There was a weak positive correlation between STOP-Bang score and ESS score (τb = 0.244, p = .000). We also found a statistically significant, although negligible, correlation between the STOP-Bang score and the number of accidents (τb = 0.096, p = .039) and near accidents (τb = 0.120, p = .008). ConclusionOur results suggest that a considerable proportion of Ecuadorian bus drivers were at high-risk for obstructive sleep apnea. Higher STOP-Bang scores were correlated with an increased number of accidents and near accidents. Additional studies are needed to determine whether additional interventions could increase road safety by taking care of undiagnosed and untreated OSA cases in a timely manner.

Factors Influencing the Use and Abuse of Drugs by Commercial Drivers: A Case of Commercial Drivers in Ghana

Introduction: Significant number of road accidents can be attributed to drug use and drunk driving globally. The increase in the number of road traffic accidents in a report by the Ghana National Road Safety Commission, calls for a review of drunk driving in the country. The study was conducted to determine the types and use of drugs by drivers in Ghana. This will determine the social and cultural factors that influence drug driving. Methodology: We developed and introduced a self-administered questionnaire using a sample of 300 questionnaires. These were administered and carefully edited to ensure some level of consistency, clarity and reliability in the information gathered. Purposive sampling approach was used in the selection of commercial bus stations and cargo stations of selected regions depending on the locations of these stations and the population of vehicles. Backward elimination regression model-building technique was used in the selection of significant variable(s) into a fitted logistic regression model. Five percent statistical level of significance was required for a variable to stay in the model. Results: Commercial bus drivers who responded or participated in this study were male adults within the active age and forty one percent were illiterate. About, thirty four percent of these commercial drivers admitted to using drug when driving and seventy percent of these drivers learned how to drive from unapproved driving institutions. Educational levels of these drivers, hours used to drive, how the commercial drivers were trained and distance they traveled were the most significant variables associated with the use of drug by commercial drivers. Conclusion: In conclusion, there exists significant association between Levels of educational, distance traveled, time used in driving and drug Use by these commercial drivers. Drunk driving is a major threat to the development of Ghana. This threatens our transportation industry and measures ought to be taking to address this problem.

Ergonomic assessment of work-related musculoskeletal disorder and its determinants among commercial mini bus drivers and driver assistants (mini bus conductors) in Nigeria.

Work-related musculoskeletal disorder (WMSD) is a leading causes of occupational injury and disability among drivers and workers in the transport industry. This study evaluated the ergonomically assessed WMSD and its determinants among Nigerian commercial mini bus drivers (BD) and mini bus conductors (BC). A total of 379 participants (BD = 200, BC = 179) were purposively sampled for this exploratory cross-sectional study. Participants' WMSD and work related variables were respectively assessed using the standardized Nordic questionnaire and a content-validated, Driving Work Station Assessment (DWSA) form. Data were analyzed descriptively and inferentially using chi-square and logistic regression. The level of significance was set at α = 0.05. The participants were aged between 20 and 66 years, with a mean age of 33.26±10.76years (BD = 38.42±10.22years, BC = 27.50±8.13years); most of whom consumed alcohol (84.4%) and experienced severe job stress (73.4%). There was a high prevalence (95.8%; BD = 94.5%, BC = 97.8%) of WMSDs, the lower back (66.8%) and upper back (54.1%) had the highest regional prevalence of WMSD. The BC (BC vs BD) had significantly (p<0.05) higher prevalence of Neck (47.7% vs 21.5%) and upper back (80.4% vs 30.5%) WMSDs. Conversely, the BD (BD vs BC) had significantly (p<0.05) higher prevalence of low-back (85.0% vs 46.4%), knee (25.0% vs 9.5%), elbow (11.5% vs 3.9%), and wrist (10.5% vs 3.4%) WMSD. There was a significant association between WMSD and each of work duration (X2 = 11.634, p = 0.009), work frequency (X2 = 8.394, p = 0.039), job dissatisfaction (X2 = 10.620, p = 0.001) and job stress (X2 = 16.879, p = 0.001). Working beyond 4days/week (OR = 10.019, p = 0.001), job dissatisfaction (OR = 1.990, p = 0.031), constrained working postures (OR = 5.324, p = 0.003) and fatigue (OR = 4.719, p = 0.002) were the predictors of WMSD. Job stress, work duration and work frequency, posture and fatigue are important determinants of WMSDs among mini bus drivers and their assistants in Nigeria. Ergonomics training intervention for this population is recommended.

Sleep Disorders and Risk of Motor Vehicle Accident

Driving is a complicated process that demands coordination between a range of neurocognitive functions, including attention, visuo-perception, and appropriate judgment, as well as sensory and motor responses. Therefore, several factors may reduce the driving performance of an individual, such as sleepiness, distraction, overspeeding, alcohol consumption, and sedative drugs, all of which increase the hazard of motor vehicle accidents. Among them, drowsy driving is a major cause of traffic accidents, leading to more serious injuries as compared to other causes of major traffic accidents. Although sleep disorders have been highly associated among drowsy drivers, they are often untreated and unrecognized as a disease. In particular, obstructive sleep apnea and narcolepsy are some sleep disorders that are highly related to traffic accidents. Insomnia, which can cause inadequate sleep duration and promote sedative effects from sleeping pills, may also cause traffic accidents. These conditions are especially applicable to commercial bus or truck drivers, nocturnal workers, and shift workers, who are highly vulnerable to drowsy driving. Therefore, assertive screening and management of sleep disorders are necessary in general private drivers and relevant occupational drivers.