Bus Operator Workstation Design for Improving Occupational Health and Safety (2016)

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

8Problem Statement In 1997, TRB published TCRP Report 25: Bus Operator Workstation Evaluation and Design Guidelines. The report served as a reference for transit agencies seeking to evaluate and procure buses based on ergonomic considerations affecting musculoskeletal demands and human fac- tors considerations for bus operators. Since the publication of TCRP Report 25, significant progress has been made in bus opera- tor workstation design and its impact on bus operator health and safety. TCRP recognized the importance of producing an up-to-date document covering available options for bus operator workstation evaluation and design to improve bus operator health and safety and reduce costs associated with liability, time loss, and disability. TCRP Project C-22 called for research propos- als to do the following: • Better assess the bus operator workstation in the context of occupational health and safety; • Examine how bus operator workstation design guidelines can best be used in the bus design and procurement processes; • Produce user-friendly guidelines for improving bus operator workstation design, including but not limited to the physical, cognitive, and perceptual environments; and • Develop a planning and decision-making tool that improves future bus procurements to ben- efit bus operator health and wellness and transit system safety performance. The research was expected to help transit industry stakeholders, especially transit agencies and manufacturers, integrate suggested procurement practices and improved technologies into bus operator workstation design, and to address operational and economic demands. Project Objectives The initial objectives of TCRP Project C-22 were to produce the following: 1. Potential strategies, practices, and policies for reducing bus operator injury and illness, public liability, and property damage attributable to bus operator workstation design in the U.S. public transit industry; 2. Guidelines to update the TCRP Report 25: Bus Operator Workstation Evaluation and Design Guidelines; 3. A digital CAD model of a bus operator workstation that can be used by designers and transit agencies in bus specifications; 4. A proposal for developing a benefit/cost analysis of implementing an ergonomically designed bus operator workstation that considers (a) life-cycle costs of the workstation; (b) bus C H A P T E R 1 Project Overview

Project Overview 9 operator turnover, illness, absenteeism, and injury costs; and (c) public liability and prop- erty damage costs; 5. Strategies for transit agencies to train and support a bus procurement team that includes bus operators to effectively participate in the development of specifications for the bus operator workstation; and 6. Training material in ergonomics for bus operators to improve their health, safety, and job performance. This project was designed to assist transit agencies and bus manufacturers to integrate improved and emerging technologies into current procurement practices and improve bus operator work- station design across the transit industry. The research team captured input from bus manu- facturers, transit agencies, labor unions, and transit organization staff in the United States and Canada to develop strategies for improving effective collaboration in the bus design and procurement process. The research team identified and analyzed advances in ergonomics considerations as demon- strated in research and transit industry literature and transit bus practices. The team applied these findings to musculoskeletal demands and human factors concerns for transit bus operators in the context of several existing design guidelines. The research team used digital human modeling to pro- duce a CAD model for vehicle engineers and designers. A universal three-dimensional (3-D) model that can be accessed by anyone with PDF computer software was exported for wider dissemination of information to improve transit bus operator workstation design. The research and practice back- ground related to procurement and to ergonomics are described in the following sections. Bus Operator Health and Safety Background The public transit bus operator’s job is complex and demanding. Compared to the U.S. work- force overall, public transit workers have higher instances of low back pain, shoulder problems, carpal tunnel syndrome, and lower leg vascular problems (Bushnell et al. 2011 and personal com- munication). Bus operators in particular are exposed to a wide range of physical demands that can contribute to the observed health problems. The most commonly recognized demands are extended sitting; stressful postures affecting the back and joints; glare; and force demands includ- ing, for example, using double interlock brakes or assisting wheelchair passengers. Bus operators experience whole-body vibration and impact forces transmitted via the seat, and higher frequency vibration from the steering wheel. Navigating the road environment creates challenges and at times psychosocial stresses, such as staying aware of pedestrians, dealing with high volumes of traffic and construction, or driv- ing through poor weather conditions. In addition, bus operators face attentional and cognitive demands related to bus alerts and controls, schedule stress, and sometimes abuse or assault by passengers. These stressors can increase the negative impact of the job’s physical demands. Visual and cognitive overload from displays and auditory inputs can also lead to stress that aggra- vates the impact of the biomechanical demands. Besides negative effects on the bus operator’s health and well-being, these factors can combine to increase bus operator mental and physical fatigue, which may reduce awareness of potential vehicle or pedestrian road incidents. The complexity of the informational demands on bus operators continues to increase in today’s transit buses. Workstation Design and Bus Operator Work Demands Workstation layout and design determine the biomechanical challenges that can result in cumulative or acute strain. These challenges include reaching for manual door mechanisms,

10 Bus Operator Workstation Design for Improving Occupational Health and Safety manipulating the steering wheel in repeated 90° turn maneuvers, moving the legs and feet force- fully or awkwardly operating foot controls, repeatedly adjusting the torso to ensure safe visibility, and absorbing vibration through the seat, floor, or steering wheel. Vehicle architecture may amplify biomechanical strains; for example, there is a trade-off between the comfort of the operator workstation compartment and optimization of the design of other areas, such as the passenger walkway, passenger seating and storage, and access to the fare box. The bus needs to be big enough to maximize passenger capacity while remaining maneuver- able through city streets. Flat-front vehicle architecture tends to restrict the pedal and instrument panel space between a flat dash wall, which impedes pedal travel, steering column shaft location, and the operator’s compartment barrier. A minimized bus operator workstation typically results in a limited path to and from the seat. Typically, there is no exterior door access for the operator on the left side, and the pass-through is slim between the seat, fare box, passenger grab handles, and workstation compartment barrier in the rear of the operator seat. Variations in bus operators’ anthropometric dimensions can result in a poor fit to seat, steering wheel, mirrors, and pedals. These restrictions may be complicated by the presence of protective barriers. Workstation Impacts on Bus Operator Health and Safety These stresses and cumulative strains can take a toll not only on bus operators but also on the transportation system and the riding public in the form of absenteeism and missed bus runs. Early studies indicated that the absenteeism rate of transit bus operators was as much as three times the average rate for other blue-collar workers (Evans 1991; Winkleby et al. 1988). A recent news story (Elinson 2012) reported that at the San Francisco Municipal Transport Agency the unscheduled absence rate was 12.2% on a daily basis. In contrast, in 2014 only 2.9% of the general U.S. working population reported working less than their regular hours in the previous week, for a total of 1.5% of regular hours missed (Bureau of Labor Statistics 2015). A range of health factors, including chronic disease and stress, contribute to absenteeism (Evans 1994); but musculoskeletal disorders in particular have been shown to be higher among bus operators than in many other occupations (Alperovitch-Najenson et al. 2010a and 2010b; Gobel et al. 1998; Greiner and Krause 2006; Szeto and Lam 2007; Westgaard and Winkel 2011). The biomechanical and cognitive demands related to the design and layout of the bus operator’s workstation have been suggested as a major contributor (Tse et al. 2006; Bhatt and Seema 2012). Improving workstation design will contribute to a reduction in the preva- lence of musculoskeletal strains and other health problems faced by operators, and may limit related absenteeism. Bus Operator Workstation Design: Literature Review A growing body of research indicates the importance of bus operator comfort and safety in the success of public transit service delivery (e.g., Brunoro 2012), but the bus operator workstation has often been considered only after other concerns, including passenger seating (Grosbrink 1998). Grosbrink emphasized the bus operators’ role in identifying workstation problems: “Finally, the assessment of the driver’s area by the drivers, whose personal inter- ests should be taken into account, is of great importance. Supposedly minor details, such as placement of the driver’s bag or storage lockers for personal effects, are important for driver satisfaction.” Bus design elements such as engine placement and floor height can affect key areas of personal interaction on the bus, especially between bus operators and passengers (Napper 2009).

Project Overview 11 Comfort, in addition to safety, was an area of concern to transit agency staff, industry experts, and bus operator union officers participating in the current research. They agreed that bus operators should play a central role with their transit agencies in defining how the bus operator workstations should be designed. These requirements and guidelines should be communicated to the manufacturers. Bus Operator Participation in Bus Design Within Transit Agencies The research literature supports the importance of the bus operator in assessing and improving the workstation, as the following examples show: • An early study (Jabs 1988) used qualitative interviews of transit agency managers, driver surveys, and records review methods to identify the bus operator workstation elements that contribute to operator injuries. The concerns—seats, controls, stress, and lack of breaks— mirrored those described in the current research. Jabs remarked on the wide range of opinions on the same buses among transit agencies (and even within one location), and suggested the need for systematic data collection that is still flexible enough to incorporate opinions and qualitative assessments. Examples of research in this area include the following: – Carrier et al. (1992) assessed the bus operator workstation for the Canadian Public Transit Association. They interviewed and observed bus operators across Canada to diagram the many elements that contribute to the demands of the bus operator tasks (p.12). Carrier et al. also drafted a design priorities tree based first on health and safety concerns, then on efficiency and comfort. – Salmon (2011) defined a framework of ergonomics methods for assessing bus driver dis- traction (p. 609) that is based in existing and naturalistic data, rather than lab methods or simulators. This framework begins with data collection consisting of documentation review, subject matter expert interviews, bus driver focus groups, observational study, and ergonomic assessment of the bus operator workstation. Multiple, overlapping methods of analysis led to a definition of the sources and effects of distraction. The structure of the framework can also be applied to musculoskeletal, cognitive, and other demands of the bus operator workstation. Communicating Bus Operator Insight to Vehicle Manufacturers It is not enough just to generate good ideas in a vehicle assessment process. The findings need to influence what equipment is on the market. Research describing participatory ergo- nomics in varied work environments, including transportation, demonstrated that workers’ recommendations may not be implemented; the reasons for this need to be investigated (Driessen 2010). In addition to bus operators’ limited input within the transit agency, work- station design is hampered by lack of communication between bus operators and manufac- turers. Both groups cited this as a barrier as early as a 1982 report (Transport and General Workers Union 1982). In contrast, there are examples of successful execution of procurement based on the identifi- cation of design issues by users and interaction with manufacturers. • Bellemare et al. (2005) described a method for overcoming the mistrust and inefficiencies that may result from top-down analysis and design of a subway train cab. A team of stakehold- ers (operators, maintenance workers, engineers, operations management, and ergonomists) developed a simulated workstation (model) that allowed the research team to address the experience of operators with regard to the constraints of the workstation. The researchers felt that a trained procurement team that included operators could apply the simulated computer

12 Bus Operator Workstation Design for Improving Occupational Health and Safety model to carry out assessment and testing more efficiently than if the process were done solely by engineers and designers. • Participatory ergonomics is especially important when the initial concern of the vehicle pur- chaser may not be the most important issue. In an ergonomics assessment of a subway opera- tor’s cab, Stevenson et al. (2000, 502) found that “[a]s with many ergonomic projects, the problem initially identified by the client, viz. the detailed design of the handle of the master controller, turned out to be a less significant issue than several other factors. The question- naire and design studies indicated that the most important issues were the knee space and the ease of use of the foot pedal.” • Frieling (2012, 59) quoted a Dutch transit agency and manufacturers describing their joint, practical approach: “The use of a low-level mock-up and the input of future drivers at an early stage of the design process were essential for the successful development of this driver’s cabin for Amsterdam’s metro. The combination of experts, real drivers, and virtual manikins has resulted in a driver’s workplace in accordance with the principals of human factors.” The researchers acknowledged that some aspects of needed design were not possible to mock up and would need to be assessed in pilot phases of production. In summary, the research literature on the impact of workstation design on bus operator health illustrates a range of naturalistic, qualitative, and technical approaches to data collection and analysis. It also supports increasing the role of the bus operator, along with other stakeholders, in analyzing the workstation and designing solutions. Updated Bus Operator Workstation Design Guidelines Overview of Previous Guidelines: TCRP Report 25 TCRP Report 25: Bus Operator Workstation Evaluation and Design Guidelines was developed through TCRP Project F-4 by Pennsylvania State University in the late 1990s (You et al. 1997). The project consisted of an analysis of bus operator workstation demands and the modeling, mock-up, and testing of an improved design. The guidelines involved products and suggestions for specifications, including the following: • Bus operator workstation mock-up user evaluation; • Bus operator workstation designation of component reference points [e.g., seat reference point (SRP), right instrument panel reference point (RIPRP)], vehicle design variables, and anthro- pometric body variables, which were organized into a hierarchy and fit into design function relationship equations; • A bus operator workstation checklist of approximate design values and adjustment ranges to nominally accommodate a 5th percentile female through a 95th percentile male; and • Demonstration of suggested workstation design on a drivable prototype to a sample of bus operators. In reviewing TCRP Report 25, the research team identified two important areas for consideration in TCRP Project C-22: 1. The workstation design approach in the earlier study was based on a neutral seat reference point (NSRP) rather than neutral pedal references, and 2. The anthropometric data set of the earlier study was based on univariate linear body lengths and posture angles or range of motion. The authors of TCRP Report 25 concluded that the NSRP approach would require adjustable floors and pedals; however, the adjustable floor was not attempted in dynamic or static evaluations of the workstation because of its potential impact on safe ingress/egress from the workstation. The

Project Overview 13 authors of TCRP Report 25 also decided not to pursue adjustable pedals due to concerns about reliability. Without either adjustable floors or adjustable pedals, the assumptions of a fixed NSRP and optimized visibility were not supported for bus operators of various sizes. Current Approach The methodology chosen to develop the updated bus operator workstation design guide- lines improves upon the approach applied in TCRP Report 25. The approach presented in TCRP Report 185 allows the inclusion of design requirements from multiple international guidelines, as well as common vehicle architecture dimension characteristics (e.g., SAE J1100). Industry feedback was collected from transit agencies that would be future guidelines users. SAE Class B vehicle packaging RPs were applied to the location and positioning of the bus operator workstation seat, controls, and components. In order to place boundaries on the arrangement of the workstation elements, the research team obtained current production vehicle data. A recent survey of a North American population of commercial vehicle drivers was applied to develop multivariate manikins that became the basis for validation of the sug- gested bus operator workstation. International Transit Bus Operator Workstation Guideline Matrix As part of the literature synthesis, the research team gathered transit industry bus operator workstation guidelines from the United States and Europe. • U.S. Sources: – TCRP Report 25: Bus Operator Workstation Evaluation and Design Guidelines – Standard Bus Procurement Guidelines (APTA 2013), developed as a tool to assist with the RFP process • International Sources: – European Bus System of the Future (EBSF) Recommendation for a Code of Practice of Driver’s Cabin in Line-Service Buses (European Commission 2011) – International Organization for Standardization (ISO) document ISO 16121-1:2012(en): Road Vehicles—Ergonomic Requirements for the Driver’s Workplace in Line-Service Buses, Part 1: General Description, Basic Requirements (ISO 2012) The research team compiled comparative specifications from these publicly available sources to illustrate similarities and differences in one International Bus Operator Workstation Design Matrix. The result of the bus operator workstation guideline matrix was a feature guideline. Bus Operator Workstation Feature Guideline Design Tool 1: Bus Operator Workstation Feature Guideline is useful for determining how pre-existing or new bus operator workstations’ dimensions compare to the suggested feature dimensions. The research team used industry feedback, existing transit bus vehicle data, and the matrix of international transit bus operator workstation guidelines to construct the tool as a stand-alone guideline document with updated features. The document is intended to provide design guidance for transit bus manufacturers and transit bus agencies procuring buses. The primary scope of the document is limited to the key elements of operator workstation design that impact the health and well-being of the bus operator. Bus Operator Workstation Engineering CAD Model For Design Tool 2: Bus Operator Workstation Engineering CAD Model (listed online as “Bus Operator Workstation Engineering CAD Model”), the research team applied 2-D drawing and 3-D model data from a current production transit bus to establish the basic architecture of a transit bus operator workstation. The modeling of components was accomplished using

14 Bus Operator Workstation Design for Improving Occupational Health and Safety solid-modeling CAD. Gaps in the CAD data were filled by reverse engineering components from physical measurements of transit buses. When the vehicle CAD model was completed, the research team had a detailed benchmark upon which to build the suggested Engineering CAD Model. SAE RPs were applied to develop the operating packaging references and envelopes. Additional guidelines were applied that might enhance the Engineering CAD Model in meeting the needs of today’s procurement practices and ultimately meeting the needs of the transit bus operators. Bus Operator Workstation 3-D PDF Model and User Guide To increase awareness of the bus operator’s needs and the process by which those needs can be met through appropriate communication between the stakeholders in the procurement process, it was deemed appropriate to make a 3-D tool accessible to a wider audience than just engineers with CAD experience. To accomplish this purpose, the Bus Operator Workstation Engineer- ing CAD Model was exported into a lightweight 3-D universal file format (i.e., PDF), creating Design Tool 3: Bus Operator Workstation 3-D PDF Model (available online from the TCRP Report 185 webpage, together with a 3-D PDF user guide). The design tools and suggested procurement team practices from TCRP Project C-22 are designed for use by each transit agency to coordinate with its workforce, vehicles, and suppli- ers. The intent of TCRP Report 185 is also to enhance communications among transit agencies, manufacturers, researchers, and industry groups. Report and Tools Roadmap The chapters of this report define and explain the tools produced through the TCRP Project C-22 research and how they can be used to support effective bus procurement and help transit operators provide safe, efficient, and economical service. Chapter Guide • Chapter 2: Bus Workstation Design and Procurement Process to Protect Operator Health and Safety defines the steps and practices derived from the research interviews and surveys. It provides a background summary of the research for each phase of procurement, and illustrates the important roles played by stakeholders outside the transit agency. • Chapter 3: Training to Support the Procurement Team and Bus Operator Ergonomics lays out suggested areas of training and shows how these can enhance the procurement process. • Chapter 4: Development of Bus Operator Workstation Design Guidelines establishes the bus operator workstation packaging assumptions and steps used to develop the feature guide- line document, CAD model, and associated 3-D PDF model. • Chapter 5: Human Modeling Validation of Bus Operator Workstation Design Guidelines describes the process of human modeling simulation that was used to test the prescribed seat/ steering-wheel/pedal arrangement to determine if it would accommodate a population of U.S. commercial vehicle operators comfortably while meeting requirements for visibility and floor/pedal reach. • Chapter 6: Conclusions summarizes the processes, communication paths, and tools that, when applied during and between procurement periods, will support and deliver improvements in bus operator health and safety. • Appendix A: Bus Operator Considerations for Purchase Price consists of a proposal for developing a benefit/cost analysis of implementing an ergonomically designed bus operator workstation that considers all costs and the benefits to impacted social groups, and a discussion of a return on investment (ROI) analysis approach.

Project Overview 15 • Appendix B: Bus Operator Workstation Engineering CAD Model Specifications demon- strate the steps and specifications that were applied to the creation of the Bus Operator Work- station Engineering CAD Model and Bus Operator Workstation 3-D PDF Model tools. • Appendix C: Construction of Multivariate Manikins in Human Modeling Software dem- onstrates the steps and body dimensions applied to develop a group of simulation manikins representative of a recent U.S. population of commercial vehicle operators in a high fidelity human modeling software (RAMSIS). • The Annex to Appendices summarizes information from appendices D, E, and F regarding data collection and the methodology used during the research. Complete, unedited copies of appendices D, E, and F can be found on the TCRP Project C-22 webpage. Tools The following organization and design tools are available for download from the TCRP Report 185 webpage. To access the correct page, go to www.trb.org and search for “TCRP Report 185”. • Organization Tool 1: Bus Operator Workstation Procurement Process (listed online as “Suggested Procurement Practice for Bus Operator Health and Safety”) defines the phases, steps, and suggested practices for procurement teams to enhance bus operator health and safety. This tool is explained in detail in Chapter 2 and summarized in the online tool. • Organization Tool 2: Bus Operator Workstation Procurement Team Training (listed online as “Procurement Team Training”) is a presentation template outlining the training that sup- ports the bus procurement process described in Chapter 2. This tool is described in Chapter 3. • Organization Tool 3: Ergonomics Training for Bus Operators (listed online as “Ergonomics for Bus Operators Training Template”) provides a training plan and presentation that can be adapted by transit agencies and unions to help bus operators understand the ergonomics demands of their work, protect their health, and contribute to safer bus operation. This tool is described in Chapter 3. • Design Tool 1: Bus Operator Workstation Feature Guideline (listed online as “Bus Operator Workstation Feature Guideline”) is intended for use in determining how pre-existing or new bus operator workstations dimensions compare in 2-D to the suggested feature dimensions. It has been organized by workstation component categories. A comparison matrix of inter- national transit bus guidelines is appended to the guideline document. The development of this tool is described in Chapter 4. • Design Tool 2: Bus Operator Workstation Engineering CAD Model (listed online as “Bus Operator Workstation Engineering CAD Model” and available as either an IGS file or a STEP file) is a 3-D engineering level spatial representation of the visibility, seating, and control criteria supplied in the 2-D feature guideline. The development and validation of this tool are described in Chapters 4 and 5, respectively. • Design Tool 3: Bus Operator Workstation 3-D PDF Model (listed online as “Bus Operator Workstation 3-D PDF Model” and provided with a 3-D PDF user guide) provides a model for procurement team members and stakeholders who do not have access to complicated and expensive engineering CAD programs. The development of this tool is described in Chapter 4 and the validation of this tool is described in Chapter 5.