Bus Operator Workstation Evaluation and Design Guidelines Final Report (1997) / Chapter Skim
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Chapter 2. Work Station Design
Chapter 2. Work Station Design
Pages 11-84
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From page 11... ...
This study has suggested novel design concepts on the work station components of transit buses such as steering wheel, pedals, instrument panels to resolve the problems described by the operators in the survey and discussed by other researchers. In parallel, a systematic design approach was developed in order to analytically determine the positions, orientations, and adjustment ranges of the components, which will be discussed in the following section.
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From page 12... ...
The instrument panels containing displays and controls were investigated designing the adjustment range, panel layout, size, and locations (Appendix F)
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From page 13... ...
The functional purpose of the left instrument panel is to provide easy access for all operators to the secondary controls or controls that are used during the predriving tasks. These controls are the parking brake, the exterior mirror remote adjustment knobs, the exterior mirror defrost control, the internal and external public announcement systems, the radio controls, the run selector knob, the transmission and the ignition switch.
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From page 14... ...
Also, comfortable reach of the right arms are considered in the determination of the right instrument panel location.
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From page 15... ...
synthesis of design guideline. 2.2.1 Design Scope Identification The design scope of a bus operator workstation was identified by choosing a design datum point, setting design criteria focused on the workstation design, defining static and dynamic bus driving postures, and establishing hierarchies of design and anthropometric variables.
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~ Field Survey - Questionnaire - Mockup Test - Prototype Test Suggest Design Guidelines Figure 2. I: Systematic Design Structure for an Ergonomic Bus Operator Workstation - 2.6
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From page 17... ...
Once the eye position is chosen, other design variables of the workstation such as the seat height and seat hack rest angle, and so on, are determined consecutively. Although this DEP approach results in good visibility, large adjustments for the seat and pedals are required to accommodate 95% of the U.S.
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From page 18... ...
, which is employed in this study, encompasses the advantages from both the DEP and HRP approaches, with minimal component adjustments of the seat, steering wheel, and pedals. The SRP is defined as a point on the sagittal or medial plane of the seat located by the intersection of two planes: the compressed seat pan and seat-back.
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From page 19... ...
SRP is located 13.4 cm behind and 9.8 cm below of the H-point which correspond to the profile of the deflected seating contour of the H-point machine as shown by Figure 2.5. Minimum Visibility Marker Figure 2.4: Visibility and Reachability in the NSRP Approach \~\ ~ ~J Figure 2.5: Geometric Relationship between H-point (SgRP)
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From page 20... ...
(2) where, SB ~ i: seat back neutral vertical angle SP9: seat pan neutral horizontal angle HL`1 1: vertical length from hip pivot to SRP HLl2: horizontal length from hip pivot to SRP As an example, utilizing the equations and referencing the SgRP location specified in a seat drawing in Figure 2.6, the SRP of the seat is analytically positioned as of 1 1.7 cm behind and 10.7 cm below of the SgRP.
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From page 21... ...
The metric visual constraint is geometrically approximated to a 30° downward sight line with a range of less than 3 degrees for the population (Bucciaglia, 19951. Therefore, after determining the locations of DEP from NSRP for the 5th percentile female, the 50th percentile, and the 95th percentile male in the workstation, sight lines were drawn from the DEPs to locate the instrument panels and the steering wheel below the 30° downward exterior visibility requirement.
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From page 22... ...
and the instrument panels were located so that all bus operators who are in the 5th percentile female to the 95th percentile male range could reach and operate them conveniently. 2.2.~.3 Standard Bus Driving Postures To design the workstation from the ergonomic viewpoint, it is necessary to first define a standard bus driving posture.
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From page 23... ...
Figure 2.7: Static Driving Posture - 2.13
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From page 24... ...
~ ~=. Figure 2 8: Dynamic Driving Posture -2.14 ~ - )
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From page 25... ...
Accordingly, the identification of the design variables was conducted by breaking the system into the subsystems or into the sub-subsystems if necessary and then matching the dimensional attributes to the sub-subsystems consecutively. As a result, 242 design variables have been defined for a bus operator's workstation design.
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From page 26... ...
Table 2.2 shows the hierarchy of the design variables developed; each variable is assigned a "Code," as shown by the last column, for notation purposes. Also, the number of design variables defined for each workstation component is summarized in Table 2.3.
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From page 27... ...
Reference Point NDEP Neutral Design E e Point ~ Y NLIRP Neutral Left Instrument Pane] Reference Point NESCMRP Neutral Left Side Convex Mirror Reference Point NLSFMRP I Neutral Left sit Flat Mirror Reference Point NPMCMRP Neutral Passenger Monitor Convex Mirror Reference Point NPRP Neutral Pedal Reference Point NRIRP Neutral Right Instrument Pane]
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From page 28... ...
1 Plon ~ - 1 I . ~ _ _ ~ W_ | LlPRP_95 ~ ~ ~ L~_5 | 1 -~\ ~ 1 _ ~ _ 1 ~ B1~ ~ y L I~}/r <3 k 1 ~ r ~ Edgy J J ~P_5 1 | BPPRP ~ ~ Figure 2.9a: Reference Locations of a Bus Operator Workstation - Plan View - 2.18
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From page 29... ...
____. __ __- __i P_5 ~ E: Plo~tEcr~ ~ X | Non SdL~ L1~ 00 ~ ~ Pot | 1~ t I I/ ~ SWFP_5 | BPPRP ~ [A Figure 2.9b: Reference Locations of a Bus Operator Workstation - Side View (Left and right instrument panels are not shown)
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From page 30... ...
[ ~ - ~ m~ Whet ~ ~ 1 3 SEP_50 _ L air 1 RlPRP_50 1 J _ I .~ ~11 3' nonfat l ~ 1 LlPE? P_50 1 ~ X I Not Sdrd Lees Dee SIDi;h Pel-4-l1`e Peons I tE3 ;": Figure 2.9c: Reference Locations of a Bus Operator Workstation - Side View (Steering wheel is not shown)
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From page 31... ...
. , ~ Design Variables .
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thickness shape material pedal arm length width thickness shape material pedal length mounting width base Thickness angle resistance Code seat belt length , SL1 | seat belt width SL2 lateral distance of SBRP from NSRP SL3 horizontal distance of SBRP from NSRP SL4 SL5 SL6 SL7 vertical distance of SBRP from NSRP seat belt tension seat belt texture wheel diameter TW1 TW2 TW3 TW4 TW5 TWO TW7 TWO TW9 TW10 TW11 TW12 grip diameter wheel shape grip shape wheel plane neutral horizontal angle wheel column neutral vertical angle wheel telescope adjustment range wheel plane horizontal angle adjustment range . wheel column vertical angle adjustment range horizontal distance of NSWRP from NSRP vertical distance of NSWRP from NSRP steering wheel resistance force leering wheel CR ratio steering wheel material spoke width spoke thickness spoke angle relative to wheel plane spoke orientation angle steering wheel spoke material.
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From page 33... ...
accelerator pedal mounting base location accelerator pedal mounting base material left instrument panel length left instrument panel width left instrument panel thickness left instrument panel curvature left instrument panel horizontal angle left instrument panel horizontal adjustment range left instrument panel vertical adjustment range lateral distance of NLIRP from NSRP horizontal distance of NLIRP from NSRP vertical distance of NLIRP from NSRP left instrument panel material left instrument panel surface finish central instrument panel length central instrument panel width central instrument panel thickness central instrument panel curvature central instrument panel vertical angle horizontal distance of NCIRP from NSRP vertical distance of NCIRP from NSRP central instrument panel material central instrument panel surface finish - 2.23 IL4 IL5 IL6 IL7 IL8 IL9 IL1 0 IL1 1 IL1 2 ICI IC2 IC3 IC4 IC5 IC6 IC7 IC8 IC9
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From page 34... ...
_ right instrument panel horizontal angle _ ~_ right instrument panel horizontal adjustment range right instrument panel vertical adjustment range ~_ lateral distance of NRIRP from NSRP _ _ ve~= ~ s~e ~ FIR ~- t~ NS d' _ right instrument panel material right instrument panel surface finish left side flat mirror length left side flat mirror width Oft side flat mirror lateral angle IR7 IR8 IR9 IR1 0 IR1 1 IR1 2 ML1 ML2 ML3 ML4 ML5 eft side flat mirror vertical angle _ eft side flat mirror lateral angle adjustment _ range _ _ eft side flat mirror vertical angle adjustment _ range lateral distance of NLSFMRP from NDEP _ ML6 ML7 ML8 ML9 ML1 0 ML1 1 ML1 2 ML1 3 ML14 ML1 5 ML1 6 ML1 7 ML1 8 ML1 9 MV1 MV2 MV3 MV4 MV5 MV6 horizontal distance of NLSFMRP from NDEP vertical distance of NLSFMRP from NDEP left side flat mirror reflectance left side convex mirror length eft side convex mirror width . eft side convex mirror curvature left side convex mirror lateral angle left side convex mirror vertical angle _~ ~ ~ ~ ~sora.'~ ADS horizontal distance of NLSCMRP from NDEP ertcal distance of NLSCMRP from NDEP eft side convex mirror reflectance rear view mirror length ~ V~ ~r w~1 rear view mirror lateral angle rear view mirror vertical angle _ rear view mirror lateral angle adjustment range _ rear view mirror vertical angle adjustment range lateral distance of NRVMRP from NDEP _ horizontal distance of NRVMRP from NDEP vertical distance of NRVMRP from NDEP rear view mirror reflectance right side mirror length right side mirror width right side flat mirror lateral angle right side flat mirror vertical angle - 2.24 MV7 MV8 MV9 MV10 MR1 MR2 MR3 MR4
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From page 35... ...
_ lateral distance of NRSFMRP from NDEP horizontal distance of NRSFMRP from NDEP vertical distance of NRSFMRP from NDEP right side flat mirror reflectance right side convex mirror length right side convex mirror width right side convex mirror curvature right side convex mirror lateral angle right side convex mirror vertical angle lateral distance of NRSCMRP from NDEP MR7 MR8 MR9 MR10 MR1 1 MR12 MR1 3 MR14 MR15 MR1 6 MR1 7 . MR1 8 MR1 9 MP1 MP2 MP3 MP4 MP5 horizontal distance of NRSCMRP from NDEP vertical distance of NRSCMRP from NDEP right side convex mirror reflectance passenger monitor convex mirror length passenger monitor convex mirror width passenger monitor convex mirror curvature passenger monitor convex mirror lateral angle .
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From page 36... ...
horizontal distance of the front face of modesty panel from NSRP _ Design Variables _ 1 st Level 2nd Level 3rd Level 4th Level Peripheral modesty length Workspace panel width (E)
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From page 37... ...
Table 2.3: Summary of the Number of Design Variables of a Bus Operator Workstation Bus Operator Workstation Component | Number of Design Variables Ist Level 2nd Level # of 2nd Level # of fist Level Headrest T 12 ~ Seat l Seat Back T IS 1 53 I Seat Pan T 19 1 l ~Seat Belt T 7 l Steering l Wheel | 14 | 19 Spokes 5 Pedals T Brake Pedal T 24 T 48 Accelerator Pedal 24 l Left Instrument Pane] | 12 ~ Instrument Panel ~ Center Instrument Pan' I T 9 1 33 I Right Instrument Pane T 12 l I Left Side Flat Mirror I lo T 1 I Left Side ConvexMirr'~r T 9 1 ~Rear View Mirror ~10 l Mirror | Right Side Flat Mirro: | 10 | 57 | Right Side Convex Mir' fir | 9 l Passenger Monitor Convex Mirror Windshield I Windshield T 6 1 l Pillar 3 Farebox I T 6 T 6 l I PersonalLocker I 6 T Peripheral l Modesty 'anel | 5 | 17 Workspace I Cold Blast P otector T 4 l l Wastebasket T 3 .
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From page 38... ...
aesthetic design variable. In this part of the study, only ergonomic design variables have been focused in the development of ergonomic design guidelines for a bus operator workstation.
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From page 39... ...
are classified into master design variables because their dimensions could influence other design variables such as the wheel plane horizontal angle adjustment range (TW8) , the left instrument pane]
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From page 40... ...
(B) ~t b~ m~ middle seat back width lower seat back width This ergonomic design study has mainly focused on the master and the slave design variables which are related to ergonomic characteristics for the development of design guidelines.
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From page 41... ...
such as visual field and movement ROM are summarized as for both values of the population extremes, comfort ranges, and the joint angles for standard driving posture assumed in this study.
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From page 42... ...
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From page 50... ...
In addition, Rebiffe (1966) cites Morant in stating that "there are complex relations between the different dimensions and in most cases a change in one or more of those measurements of a driving position would necessitate changes in the other dimensions." Thus, it is not appropriate to determine the design variables independently because there are complicated relationships between the design and anthropometric variables.
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From page 51... ...
and the seat back neutral vertical angle (SBll) are identified as the most influential design variables (about 33370 total)
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From page 52... ...
The table indicates that the adjustment ranges of the steering wheel, the instrument panels, and the pedal pivots may be determined after resolving the higher priority design variables. Table 2.9: Example of Relative Dependence of Slave Design Variables No Slave Design Variable Relative Dependence i| (Unit: %)
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From page 53... ...
Thus, it is necessary to analyze the seat dimensions more thoroughly to obtain correct design results. The steering wheel, pedals, instrument panels, and mirror locations are highly dependent on the design dimensions of the seat.
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From page 54... ...
I) should accommodate the variation of the associated anthropometric dimensions such as the lower body link length and joint angles from the 5th percentile female to the 95th percentile male.
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From page 55... ...
A designer can easily obtain a specific value of the design variable by substituting known values or data of its related design variables and anthropometric variables into the functional design relationship. The advantage of these functional relationships is that there is no ambiguity in the final design because every workstation design variable is explicitly determined by defining the geometric relations of the design and anthropometric variables.
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From page 56... ...
These procedures are given for both the Class A and Class B (which applies to transit buses) vehicles, and for three different classes of operator heights, the Ah percentile female, the half way position between large and small humans, and the 95th percentile male.
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From page 57... ...
, . Related Related Anthropometric Variables _ Design Variables | Geometric Drawing | .
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From page 58... ...
Thus, this design process can be easily applied when a different standard bus driving posture or a different design target population is considered. This study has developed design functions (Table 2.12)
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From page 59... ...
needs to incorporate the range of PA9 (18.4 cm) to accommodate the US population from the 5th percentile female to 95th percentile male.
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From page 60... ...
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From page 61... ...
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From page 62... ...
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From page 63... ...
The established systematic design structure comprises various broad and detailed analyses to produce ergonomic design guidelines for a bus operator's workstation. In the ergonomic design process, the design scope was defined by the identification of design variable and human variable hierarchies, the selection of design criteria and reference point, and the determination of standard bus driving postures.
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From page 64... ...
recalculating relevant ergonomic design values for different population groups. Thus, particular vehicles can be efficiently "tailored" to particular customers, i.e., transit systems, depending upon their anthropometric characteristics.
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From page 65... ...
_ ~ - _ _ __ ~. 7~ C Hanain~ Pedals Left Instrument Panel (LIP)
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From page 66... ...
Led Unspent Pane! Reference Point Smog Female ~ ~Large Male Right Instrument Pane]
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From page 67... ...
52.07 113.03 69.85 Steering Column BasePiYotPoint ~ 6196 ~ i ~ .65 _\ g57 Workstation Origin Notes: I) Length units are in cm.
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From page 68... ...
I= ~ ;-~' r r ~ Is m 66.04 48.5g nib ,~ i' I, 72.39 41.28 _Workstation Origin Notes: I) Length units are in cm.
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From page 69... ...
The jury consisted of 64 males, 39 females, with 14 professional bus operators or transit personnel. The average small female was actually 0.8 cm taller than the 5'h percentile female specified in SAE J833; the average large male was I.5 cm shorter than the 95th percentile male defined in SAE J833.
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From page 70... ...
Table 2.15: loins Angle Comparison Joint Angle Comfort Ranges l (unit: degrees) | 15~ 110 60 ~ 85 95 ~ 135 -5 ~ 20 Elbow FIexion Hip FIexion Knee FIexion Ankle Plantar (Note)
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From page 71... ...
Moreover, it was noted that the transit bus operators tended to evaluate the workstation more highly than the non-operators.
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From page 72... ...
Large Small Med. Large Total Female Female Female Male Male Male Population Group Figure 2.1 8: Visibility Evaluation Result of Mock-up 5 4.5 4 3.5 Rating 2.5 1.5 0.5 .4.6 ___ ______________ _______ .4.4 .4.3 44.3 ,`4.2 ___ - .4 44.4 O v Small Med.
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From page 73... ...
Large Total Male Male Male Population Group Figure 2.20: Comfort Evaluation Result of Mock-up 5 5 - - - _ _ _ _ _ _ _ ~ .4.8 44.8 4.5 ~ 3.5 3 Rating 2.5 0.5 Small Med. Large Female Female Female _ _ _-*
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From page 74... ...
. This information is helpful in order to determine the actual required adjustment ranges or to verify if a particular adjustment is even required.
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From page 75... ...
From the results of the evaluation, three major comments can be made: (~) the workstation is able to accommodate a population ranging from the 5th percentile female to the 95th percentile male, (2)
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From page 76... ...
However, the last measure, ease of ingress/egress, had a larger standard deviation than the previous measures. This is indicative of many jurors' opinion that the operator seat should swivel.
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From page 77... ...
, and also to provide sufficient visibility, acceptable reach, and comfortable driving posture for the population while performing the bus operating tasks. · Evaluate the bus workstation with a human model simulating the bus operating tasks in terms of - visibility of the displays on the instrument panel and out-of-windows, - 2.67
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From page 78... ...
were simulated for the human models in JACKS. During the simulation of the bus operating tasks, the human model motions were governed by a set of virtual kinematic constraints related to each bus operating task.
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From page 79... ...
Metrics comfort, adjustability Tilt and telescope the steering column, or tilt the steering wheel based on the seat position maintaining the static driving posture and the 30 degree downward visibility requirement simultaneously. Shift the bus into gear on the left instrument panel.
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From page 80... ...
Simulating the bus operating tasks under the kinematic constraints previously declared, the adjustable components were located iteratively until the human-workstation mode] satisfied ergonomic principles such as visibility, reach, and comfort.
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From page 81... ...
i Design Values steering wheel column telescope 11 cm (upward +, downward: -) steering wheel hub tilt 10 deg (clockwise: +, counterclockwise: -)
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From page 82... ...
adjustment of workstation components. simulation of bus operating tasks under specified kinematic constraints.
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From page 83... ...
The designated adjustment ranges were evaluated with respect to the degree of satisfying ergonomic requirements such as good visibility, acceptable reach, postural comfort, and sufficient adjustability. A valid transit bus operator's workstation design was produced through iterative design modifications and simulations.
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