Analysis and Assessment of Passenger Comfort Level in Sustainable Public Bus Transportation System

Passenger comfort and safety is one of the main factors in making the experience of using public transportation more comfortable and attractive to passengers. This study aims to assess facility design factors such as seats and handrails that are related to ergonomics, in addition to design factors, namely safety factors by identifying and minimizing hazards that can occur to passengers and procedures that need to be carried out in the event of an accident. To assess the comfort of passengers on the bus, it was measured using the Rapid whole-body assessment (REBA) guidelines, Rapid Upper Limb Assessment (RULA) and anthropometry to accurately measure body posture, as well as Quality Function Deployment (QFD). As the result, the new handle and passenger seat were proposed to comply with the ergonomic perspective. How much level of Customer satisfaction increase, can be seen in the result of this research. From using REBA Method there’s a change of score in value from before using our design customer posture got 4 for body posture evaluation score, and after using our design costumer posture score got 3 for body posture evaluation score. From using RULA method there’s a change of score in value from before using our design customer posture got 4 for body posture evaluation score, and after using our design costumer posture score got 2 for body posture evaluation score. It is concluded that the new design work and proof the new design was comply with ergonomic aspect. With this research, it will be beneficial for the sustainability of consumer comfort in Transjakarta public transportation. Because with the realization of the results of this research, improvements in Transjakarta public transportation facilities to support consumer comfort can be achieved and increase customer satisfaction.


Introduction
Public transportation in Indonesia is one of the means provided by the government for people of different age groups to use.These facilities are part of the government's efforts to serve the public and reduce the use of private vehicles in Indonesia.Over time, the types of government-provided transport have increased, including trains, minibuses (known as "Angkot") and the age-old bus selection.Buses have long been a familiar means of transportation and are used by a large number of people.In recent times, technological advancements and new facilities have made buses one of the most widely used means of public transport in urban areas.Transjakarta, a type of bus, is widely used in the capital, Jakarta.Transjakarta buses offer more features than previous modes of transport such as "mini metro" and "Kopaja".Despite the improvements, Transjakarta buses still have shortcomings, especially in terms of IOP Publishing doi:10.1088/1755-1315/1324/1/012067 2 passenger comfort.Passenger comfort is very important to increase public interest in using public buses [1], as passenger satisfaction is a major factor influencing their willingness to use public buses.use public transport [2].Because passenger is the judge of the facilities and service quality [3].There are several studies that have been conducted on buses have been carried out in recent years.Application of public transportation has been widely discussed among researchers, such as fuzzy approach for selection of buses [4], etc.Therefore, we conduct research on public transport, especially buses, with a focus on passenger comfort.This research is motivated by the lack of studies that specifically address this topic in Indonesia.
Public Transportation was one of the best solutions for alleviating traffic congestion [5], which are common in many Indonesia.Our analysis of these studies revealed shortcomings in Indonesia's bus system.Therefore, this study aimed to assess and address these gaps, focusing on improving passenger comfort on Transjakarta buses.Public transportation Passenger comfort evaluation is a multi-criteria assessment [6] and which in this research focusing on their facilities.
To improve passenger comfort, this study uses ergonomic methods, including the REBA method, to evaluate and improve the current conditions of buses in Transjakarta.The REBA method assesses passengers' body posture, determining comfort levels and potential risks associated with existing facilities [7].Data for this study came from observations, measurements and questionnaires provided to Transjakarta bus passengers, targeting a sample of 100 passengers.The data collected was used in the Quality Function Deployment (QFD) approach to determine customer satisfaction and opinion, thereby providing specific goals related to the desired of passengers and create products that match passenger satisfaction [8].The products were created based on passenger satisfaction, supported by anthropometric methods to tailor the design to the average Indonesian body.Bus seat structure design, angle, parameters, dimensions, and related data can have a significant impact on the comfort of the human body while riding [9].
Based on the literature review, it is found some similar things and differences between this research and literature.Overall, between literature and this research discuss about the importance of passenger comfort and safety in public transportation.However, this research discusses in general facilities design factors and proposes specific improvements based on ergonomic assessments.On the other hand, the literature mostly discuss about targets passengers with mobility constraints and aims to design an ergonomic to reach their specific discomforts and how to improved it.This research is important because we can know about the reason of customer discomforts using public transportations specifically Transjakarta and we can improve costumer comfort with innovation product.

2.
Methodology Numerous factors can be taken into account and considered to assess passenger comfort, such as vehicleinduced vibrations, maximum passenger density, oxygen levels, temperature, passenger body posture, and the quality of bus facilities.These factors need to be considered when evaluating passenger comfort.When calculating comfort, we are focusing on assessing passenger body posture and the existing bus facilities.Therefore, several processing methods are going to be utilized in this research, including REBA (Rapid Entire Body Assessment), which is one of the most effective ways to measure passenger body posture during standing on the bus.
The REBA method assesses scores based on the examination of passenger body structure and position.The assessment starts from the smallest scale of 1 to the highest of 11, where the obtained value represents the risk of injury that could affect passenger comfort and safety.RULA (Rapid Upper Limb Assessment) is also one of the most effective methods to measure passenger body upper posture [10].RULA uses the same method of assessment and calculation to determine passenger body structure point as REBA.
Quality Function Deployment (QFD) is another crucial method in this research.It is used to process the results of passenger surveys, which then are considered and analyzed to obtain the best outcomes based on survey responses and overall considerations.The 5-point Likert scale is one of the data collection methods used in this research.The survey was distributed to assess aspects of the available Transjakarta facilities.This method is used to gather survey data, which used to evaluate weaknesses and deficiencies that still exist and to optimize the results of the research.

3.
Results and Discussions When evaluating passenger comfort, the author conducts direct observations to identify various aspects that can influence the level of comfort.Various aspects assessed by the researcher in this study include the passenger's body posture, the size of the facilities used by passengers when boarding the bus, and questions to directly assess passengers' opinions about their experience using the Transjakarta bus.The assessment yield research results aimed at improving the comfort quality of Transjakarta bus passengers.

3.1.
REBA Method The REBA method, which stands for Rapid Entire Body Assessment, is an assessment method used to measure the overall body posture of Transjakarta bus passengers.To apply the REBA method in this study, the researcher needs the measurements of body posture angles collected directly during data collection.The assessment is based on body positions, including neck position, body position, leg position, workload, upper arm position, lower arm position, wrist position, grip, and activity.Body positions are analyzed using the Ergo Fellow software, where each body posture position was assessed and assigned a score.A higher score indicates a higher risk of ergonomic hazards, while a lower score indicates a lower risk of ergonomic hazards experienced by Transjakarta bus passengers.

Figure 1. REBA -Current Score and Explanation
The assessment results of the REBA method (Figure 1) on passenger body posture while standing prior to changes yielded a score of 4. This score was obtained based on the following body posture criteria: neck posture forming an angle of 0 to 20°, body posture in a straight position, leg posture forming a leaning position with both legs, load lifted less than 5 kg, upper arm posture forming an angle greater than 90°, lower arm posture forming an angle of 0 to 60° or greater than 100°, wrist posture forming an angle of 15° upwards or 15° downwards, sufficient grip condition, and engagement in one type of activity lasting more than 1 minute.This assessment (Figure 2) indicates a moderate level of Ergonomic Hazard risk, suggesting that further investigation is needed, along with imminent changes, to enhance passenger comfort levels.RULA Method To reduce the obtained score, proposals is introduced to address the score's aspects.The suggested improvement involves the passenger's grip position, which has transitioned from being sufficient to being good.This enhancement arises from modifying the shape, size, and underlying material of the gripping device used by passengers.As a result (Figure 3), the calculated score decreases to 3, signifying a low level of Ergonomic Hazard risk and much greater safety for passengers.

Figure 3. RULA -Result
The assessment results of the RULA method on passenger body posture while seated prior to any changes yielded a score of 4. This score was derived from the passenger's body posture divided into two sections: Part A and Part B. In Part A, the upper arm posture forming an angle of 20° forwards and backwards, the lower arm posture forming an angle of 60 to 100°, the wrist posture forming 0°, and the wrist twist posture forming 0° were identified.In Part B, the neck posture forming an angle of 10 to 20°, the trunk body posture forming an angle of 0 to 20°, and the leg posture not making full contact with the floor were identified.Following this, the assessment of muscle use and load was conducted for both sections.In Part A, muscle use was static with the same position maintained for more than 1 minute, while in Part B, muscle use was static with the same body position maintained for more than 1 minute.This assessment (Figure 3) indicates an Ergonomic Hazard risk level of action level 2, suggesting the need for further investigation and the possibility of implementing changes to enhance passenger comfort quality.
In Part A, the upper arm posture forming an angle of 20° forwards and backwards, the lower arm posture forming an angle of 60 to 100°, the wrist posture forming 0°, and the wrist twist posture forming 0° were identified.In Part B, the neck posture forming an angle of 10 to 20°, the trunk body posture forming an angle of 0 to 20°, and the leg posture not making full contact with the floor were identified.Following this, the assessment of muscle use and load was conducted for both sections.In Part A, muscle use was static with the same position maintained for more than 1 minute, while in Part B, muscle use was static with the same body position maintained for more than 1 minute.This assessment indicates an Ergonomic Hazard risk level of action level 2, suggesting the need for further investigation and the possibility of implementing changes to enhance passenger comfort quality.

Figure 4. RULA -Innovation Score and Explanation
To decrease the obtained score, proposals is introduced for addressing the score's aspects.The proposed improvement focuses on Part B, which involves the body posture of the neck forming an angle of 0 to 10 degrees, the trunk body posture forming 0 degrees, and the leg posture being planted.Posture improvement is achieved through changes in seat size and seat materials that enhance passenger comfort.As a result, the final score obtained is 2 (Figure 4), indicating that the body posture condition is now good and ergonomic.

Quality Function Deployment (QFD)
The QFD method, or Quality Function Deployment, is a systematic approach used to translate customer needs and desires into product design and development processes.This method is employed to ensure that the designed product meets the required needs and customer desires, as depicted in Figure 5. From the questionnaire, the results revealed that 68.6% of 51 respondents felt the main deficiency in the bus was related to its comfort level.Additionally, 43.1% of the respondents expressed a desire for improvements in the comfort of Transjakarta bus seats and handles.Regarding seat enhancements, 47.1% of the respondents preferred improvements in seat material.Similarly, 43.1% of the respondents indicated a need for handle enhancements in terms of materials.In terms of desired room temperature, 54.9% of the 51 respondents chose a room temperature range between 16 and 20 °C.Furthermore, 82.4% of the respondents were satisfied with the current legroom layout, and 52.9% of the respondents showed a preference for forward-facing seat positions in the bus layout.
In the HOQ results of the QFD, it was determined that from the collected survey data, there are four types of customer requirements: hand grip comfort, seat comfort, bus room temperature, and layout.To fulfil these customer requirements, the author creates functional requirements containing elements that address the customer requirements or passenger preferences.The functional requirements include handgrip and seat materials, hand grip and seat shapes, temperature control, legroom, and walkway space.An empty circle represents a moderate relationship, a solid circle indicates a strong relationship, and an inverted triangle signifies a weak relationship.From this analysis, strong relationships were found between hand grip comfort and hand grip materials and shape, seat comfort and seat materials and shape, as well as bus room temperature and temperature control.Weak relationships were found between hand grip comfort and walkway space, and layout with hand grip and seat shape.Once these relationships are understood, a comparison can be made between the improvements made and the competitor products, which include conventional buses, public vans (Angkot), taxis, and DAMRI buses (Figure 6).Ratings from 1 to 5 were assigned, with 1 being the lowest and 5 being the best.The comparison was made against the values of customer requirements: hand grip comfort, seat comfort, bus room temperature, and layout.The evaluation scores for the improved Transjakarta bus were hand grip comfort 5, seat comfort 4, bus room temperature 5, and layout 4. In contrast, conventional buses scored hand grip comfort 4, seat comfort 3, bus room temperature 3, and layout 3. Public vans (Angkot) score hand grip comfort 1, seat comfort 2, bus room temperature 2, and layout 2. Taxis scored hand grip comfort 2, seat comfort 5, bus room temperature 4, and layout 4. Lastly, DAMRI buses scored hand grip comfort 1, seat comfort 5, bus room temperature 4, and layout 4.
Customer importance ratings were utilized to gauge the significance of customer requirements, with values ranging from 1 to 5, where higher values denote greater importance.The results indicated hand grip comfort as having a value of 5, seat comfort with a value of 5, bus room temperature with a value of 1, and layout with a value of 2. By considering the customer importance, the relationship between customer and functional requirements, it can be deduced that the necessary enhancements were in hand grip comfort and seat comfort.Improvements include adjusting the size of these aspects based on anthropometric measurements to provide comfortable dimensions for the average Transjakarta bus passenger.Material upgrades involved adding foam or rubber layers to the hand grip for enhanced comfort, and modifying the seat material, reinforcing the sofa and plastic components, thus improving their strength and comfort.

3.4.
Anthropometrics Anthropometrics is the science used to analyze human body dimensions.These measurements are used to obtain optimal design values for seats and hand grips.The measurement data (Table 1) was collected from samples directly taken during the researcher's visit to the Transjakarta bus depot at PT Transjakarta HQ.The data includes measurements of bus seats, hand grips, and other data collected and sampled from 102 individuals.These measurements were conducted following anthropometric measurement guidelines to derive average sample dimensions.
In processing the data from the obtained 102 samples, the average values of their body measurements were calculated.These average values are necessary to serve as the primary design dimensions for the new proposed hand grip and seat improvements aimed at enhancing passenger comfort.The guidelines were divided into two sections: overall body section (Figure 7) and hand section (Figure 8).Body measurements taken based on the guideline numbers are as follows: number 6 with an average value of 57.36 cm, number 8 with an average value of 42.32 cm, number 9 with an average value of 35.17 cm, number 15 with an average value of 46.50 cm, number 16 with an average value of 37.84 cm, number 17 with an average value of 46.35 cm, and number 18 with an average value of 36.43 cm.Assessment of the hand section based on guideline numbers includes: number 12 with an average value of 7.86 cm, number 13 with an average value of 9.51 cm, number 16 with an average value of 5.33 cm, number 17 with an average value of 19.26 cm, and number 18 with an average value of 14.01 cm.The 3D design of the innovated seat (Figure 9) and handle (Figure 10) illustrated here represent the final form of the seat and handle design that has been created using Inventor based on anthropometric methods.The enhancements incorporated into the latest seat and handle design are grounded in the measurements obtained from the body and hand measurement guidelines.The improvements introduced in the new seat and handle design offer noticeable benefits.
For the seat design, the enhancements include an increase in seat size.The previous smaller dimensions have been transformed into a larger, more comfortable seating area.Additionally, the footrest position for passengers, previously too high and preventing proper contact with the floor, has been adjusted for comfortable footing.In the case of the seat's backrest, the angle and dimensions now align with recommended passenger guidelines, enabling proper sitting posture with a 0-degree incline.
As for the handle design, improvements have been made to its thickness, resulting in a more substantial grip that significantly enhances passenger comfort when holding the handle.The hole size of the handle has also been reconfigured according to measurement guidelines, ensuring it accommodates a broader range of hand sizes, providing a comfortable grip for passengers across the board.

Conclusion
The REBA method was chosen to assess the body posture of standing passengers using the bus handle.The assessment revealed that the current handle design still lacks in its grip comfort and is slippery to hold, which is a significant concern reported by passengers.
The RULA method was chosen to evaluate the body posture of passengers seated on the bus seats.The assessment results indicated that the current posture of passengers is not optimal and may potentially pose risks to passengers.Based on this paper, it is evident that changes are needed in the seat design and dimensions to improve passenger comfort.
The proposed solutions include changing the existing plastic handle material to rubber for a more comfortable and non-slip grip.For the seat innovation, modifications involve replacing the polypropylene seat frame with stronger ABS plastic material, and changing the seat cushion filling from regular foam to memory foam.
The previous seat and handle designs exhibited shortcomings, which were validated through the application of REBA, RULA, and QFD methods.To address these shortcomings, the writer developed an innovative seat and handle design based on the principles and methods of anthropometry.The size data used for creating the new design was derived from measurements of 102 students from Binus B 24.The seat and handle designs resulting from this research, driven by anthropometric principles, are expected to yield optimal seat dimensions for Transjakarta bus passengers, thereby enhancing their comfort during bus rides.

Conclusion
The REBA method was chosen to assess the body posture of standing passengers using the bus handle.The assessment revealed that the current handle design still lacks in its grip comfort and is slippery to hold, which is a significant concern reported by passengers.
The RULA method was chosen to evaluate the body posture of passengers seated on the bus seats.The assessment results indicated that the current posture of passengers is not optimal and may potentially pose risks to passengers.Based on this paper, it is evident that changes are needed in the seat design and dimensions to improve passenger comfort.
The proposed solutions include changing the existing plastic handle material to rubber for a more comfortable and non-slip grip.For the seat innovation, modifications involve replacing the polypropylene seat frame with stronger ABS plastic material, and changing the seat cushion filling from regular foam to memory foam.
The previous seat and handle designs exhibited shortcomings, which were validated through the application of REBA, RULA, and QFD methods.To address these shortcomings, the authors developed an innovative seat and handle design based on the principles and methods of anthropometry.The size data used for creating the new design was derived from measurements of 102 students from Binus University, Indonesia.The seat and handle designs resulting from this research, driven by anthropometric principles, are expected to have optimal seat dimensions for Transjakarta bus passengers, thereby enhancing their comfort during bus rides.

Table 1 .
List the Average Value of Body Posture and Average Values of Hand Postures Based on