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Low-floor bus design preferences of walking
aid users during simulated boarding and
alighting
Clive D’Souzaa,b,*, Victor Paqueta,b, James Lenkera,c, Edward Steinfelda,d and Piyush Bareriaa,b
aCenter for Inclusive Design and Environmental Access (IDeA Center), University at Buffalo, SUNY
bDepartment of Industrial and Systems Engineering, University at Buffalo, SUNY
cDepartment of Rehabilitation Science, University at Buffalo, SUNY
dDepartment of Architecture and Planning, University at Buffalo, SUNY
Abstract. Low-floor buses represent a significant improvement in accessible public transit for passengers with limited mobil-
ity. However, there is still a need for research on the inclusive design of transit buses to identify specific low-floor bus design
conditions that are either particularly accommodating or challenging for passengers with functional and mobility impairments.
These include doorway locations, seating configuration and the large front wheel-well covers that collectively impact boarding,
alighting and interior movement of passengers. Findings from a laboratory study using a static full-scale simulation of a low-
floor bus to evaluate the impact of seating configuration and crowding on interior movement and accessibility for individuals
with and without walking aids are presented (n=41). Simulated bus journeys that included boarding, fare payment, seating,
and alighting were performed. Results from video observations and subjective assessments showed differences in boarding
and alighting performance and users' perceptions of task difficulty. The need for assistive design features (e.g. handholds,
stanchions), legroom and stowage space for walking aids was evident. These results demonstrate that specific design condi-
tions in low-floor buses can significantly impact design preference among those who use walking aids. Consideration of ergo-
nomics and inclusive design can therefore be used to improve the design of low-floor buses.
Keywords: Transportation, low-floor bus, accessibility, walking aids, inclusive design
*Corresponding author. E-mail: crdsouza@buffalo.edu.
1. Introduction
Public transportation is an essential public service
that should be designed to benefit as many individu-
als as possible. United States (U.S.) federal regula-
tions and guidelines require transit agencies to trans-
port and accommodate mobility aids for persons with
disabilities, particularly those who use wheeled mo-
bility devices [10,11].
U.S. transit agencies are also faced with the chal-
lenge of having to accommodate other mobility de-
vices such as walkers, canes, crutches, oxygen cylin-
ders and service animals [3,5,8]. But federal regula-
tions and guidelines for accessibility on transporta-
tion vehicles [10,11] are less specific on how to safe-
ly accommodate these devices. One concern with
larger walking aids like walkers and rollators is the
stowage space needed to prevent obstruction or risk
to other passengers when they are otherwise stored in
the aisle or in seats required for other passengers.
Low-floor buses represent a significant improve-
ment in accessible public transit for passengers with
limited mobility primarily by eliminating the need for
steps at the entry doorway. However, there are still
problems associated with the interior design of low-
floor buses. These include constricted movement of
passengers in the forward area of the bus due to large
wheel-well covers, congestion due to irregular seat-
ing configurations, and the lack of adequate hand-
holds for support [3,7-9]. These challenges may be
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OS Press
particularly problematic for those who use mobility
aids.
The aim of the present study was to evaluate the
impact of interior design and crowding in low-floor
buses on boarding, disembarking, and interior circu-
lation for ambulant passengers with mobility im-
pairments using walking aids such as canes and
walkers.
2. Methodology
2.1. Simulation Description
A full-scale static simulation of a low-floor bus
was constructed to systematically evaluate human
performance across a wide variety of realistic bus
interior design configurations through reconfigurable
seating arrangements, wheelchair securement spaces,
and different conditions of boarding and disembark-
ing. Full-scale environment simulations provide a
valuable and cost-effective method for evaluating
whether the intended users can safely and effectively
perform critical tasks in the expected use environ-
ment. Ergonomics researchers have previously used
environmental simulations to evaluate design alterna-
tives pre-production and generating new design re-
quirements for transportation vehicles [2,6,12].
Based on a review of transit buses operating in the
U.S., three bus layouts were identified for simulation
purposes that differed substantially in physical con-
figuration. The designs adhered closely to federal
accessibility requirements [10] and dimensional
clearances recommended by the U.S. bus industry [1]
for aisle widths, wheelchair accessible pathways, seat
spacing and the positioning of handholds and stan-
chions. Boarding and alighting occurred over a fold-
ing access ramp of a 1:6 incline slope. Side-facing
fold-down seats were provided in the wheelchair se-
curement area to accommodate seated passengers
when the space was not occupied by a wheeled mo-
bility device.
Bus layout 1 (L1) included an access ramp in the
front doorway, a floor mounted fare payment box
positioned adjacent to the driver’s seat, two spaces
for wheelchair securement immediately behind the
front wheel-wells, and forward facing seats through-
out the remainder of the bus interior. This layout is
very typical of low-floor buses used in many U.S.
cities, e.g. Buffalo, Washington, D.C.
Bus layout 2 (L2) included ramps located at the
front and rear doorways, a wall-mounted fare pay-
ment box positioned near the rear doorway, side-
facing seats along the sides of the bus interior i.e.
perimeter seating, and two spaces located along the
curb side of the bus for wheelchair securement. The
rear doorway was used for boarding, and the front
door for alighting.
Bus layout 3 (L3) included an access ramp located
at the rear doorway, a wall mounted fare payment
box positioned near the rear doorway, a wheelchair
securement space on the road side and curb side of
the bus to the right of the doorway, and forward fac-
ing seats throughout the remainder of the bus interior.
For each of the bus layouts, two levels of crowd-
ing were simulated using seated mannequins – high
crowding where only one pair of seats were available
restricting seating choice, and low crowding where
only half the number of seats were occupied.
Study participants evaluated each of the six condi-
tions by undertaking a simulated bus journey that
included boarding from a sidewalk, fare payment
using a smart-card, locating and moving to a vacant
seat, getting into and out of the seat, moving to the
exit door and alighting (Figure 1). Participants had
the opportunity to sample different seating conditions
involving combinations of front- or side-facing seat
positions, as well as front and rear entry and exit
conditions.
Following each journey, participants were asked to
provide ratings of design related to the configurations
and interviewed to assess their difficulty in complet-
ing various aspects of the journey. Movements were
recorded using conventional video cameras and a
three-dimensional active marker motion capture sys-
tem.
2.2. Research Participants
Forty-one ambulatory adults between the ages of
18-80 years were recruited from the general public
and local organizations serving the elderly and per-
sons with disabilities to participate in the study. This
included thirteen individuals who used a walking
cane, eleven who used a walker, five who did not use
an ambulatory aid but had a walking impairment, and
twelve who did not have a walking impairment. A
majority of the sample used fixed-route buses fre-
quently, and only four walker users depended on
ADA (Americans with Disabilities Act) paratransit
services for transport. A summary of the four differ-
ent sub-groups is presented in Table 1.
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Fig.1. Photograph of the simulated environment depicting bus layout 3 with a cane user during the boarding process
Table 1
Demographic information of the study sample (n=41) stratified by use of walking aid and walking impairment.
Cane Users
(n=13)
Walker Users
(n=11)
Mild Imp.
(n=5)
Able-bodied
(n=12)
Total
(n=41)
Gender (F, M) 7 , 6 9, 2 2, 3 8 , 4 26, 15
Age: Mean (SD) yrs. 53.6 (11.1) 63.1 (10.7) 42 (10.7) 44 (9.3) 52 (13)
Bus Users (>= once a
week) 10 6 4 9 29
Difficulty walking or climbing stairs e.g. entering home, boarding a bus:
No difficulty 2 2 1 11 16
Some difficulty 10 6 3 1 20
A lot of difficulty 1 3 1 0 5
3. Results
3.1. Preference in Bus Layout Design
When asked to rate the travel conditions tested, the
layout with a perimeter seating configuration (L2)
was preferred overall in terms of physical access for
both the low and high crowding conditions. The de-
sign with forward entry and exit (L1) was consis-
tently rated poor in conditions with high crowding.
Participant preferences are summarized in Table 2.
3.2. Boarding and Alighting
Regarding preference of doorway location for
boarding, ten participants preferred the front door
while eight preferred the rear door. Sixteen partici-
pants preferred the front door for alighting, and thir-
teen preferred the rear door. Many did not express
any preference. Reasons for choosing the rear door
included “taking less time for boarding”, “less con-
strained for space”, “easier to locate a vacant seat”
and “quicker exit as most passengers sit up front”.
Regarding the use of the front door, participants
commented on “needing to interact with the driver
(in asking for directions)”, “feeling safer” and “pre-
ferring to be seated closer to the driver”.
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Table 2
Preference in bus design for layouts L1, L2 and L3, across conditions of low and high crowding.
Cane
Users
(n=13)
Walker
Users
(n=11)
Mild
Imp.
(n=5)
Able-
bodied
(n=12)
Total
(n=41)
Low Crowding
Most preferred L1 L2 L2 L2 L2
Intermediate L2 L3 L1 L3 L1
Least Preferred L3 L1 L3 L1 L3
High Crowding
Most preferred L2 L2 L2 L3 L2
Intermediate L3 L3 L3 L2 L3
Least preferred L1 L1 L1 L1 L1
3.3. Interior Movement
Interior movement to and from the seat was rela-
tively more difficult in conditions of high crowding
and noticeably problematic for walker users. The
narrower aisles adjacent to forward-facing seats en-
countered in high crowding conditions for designs L1
and L3 did not provide adequate space for walker
users to turn and orient with the seat. Participants
reported being concerned about finding a seat quickly
to avoid delays or accidently bumping into passen-
gers when moving through the aisles, and in finding a
seat that allowed storage of the walking aid without
obstructing other passengers.
A few participants also commented that finding a
seat quickly without having to walk a distance was
most paramount. Real-life experiences of the bus
taking off before the person could find a seat was
cited as the primary reason.
3.4. Seating
A large majority (91%) of the participants pre-
ferred side-facing seats over the front-facing seats.
These included 7 of 13 (54%) cane users, all eleven
(100%) walker users, 2 of 5 mildly impaired, and 8
of 12 (67%) able-bodied participants. Commonly
cited reasons were “more legroom”, “ease of getting
in to and out of the seat”, “wider aisle” and “more
room for luggage”. Three participants did not ex-
press any preference.
Walker users strongly favored side-facing seats as
it provided for legroom and space to position the
walker directly in front during sitting and standing
and without the aid of a handrail or stanchion. Dur-
ing travel, participants tried to draw the walker close
to the seat as possible with the intent of keeping the
aisle clear for other passengers.
The primary complaint against forward facing
seats was the inadequate leg-room, with walker users
particularly inconvenienced by the lack of space for
stowing the walker even when folded – although
most users preferred to travel with the walker un-
folded as it is used for support when getting into and
out of the seat. For a few cases, the bags and purses
hanging off the walker prevented it from folding
properly.
Reasons for preferring front-facing seats included
needing “to see where the bus was going”, avoiding
the “direct stare of other passengers” seated across
the aisle, “less sway” during acceleration or decelera-
tion. If the spacing between front-facing seats were
to be increased it is likely that a few more individuals
would prefer these seats over side-facing seats.
3.5. Use of support features
Among the different support features, vertical
stanchions were most preferred and frequently used
along with the horizontal handles on the back of for-
ward-facing seats primarily in seating, standing up,
and during interior movement. In general, overhead
handrails were found to be too high for effective use.
In a response to questions about support features,
more than half the number of participants (27 of 41)
commented on having found stanchions very helpful,
particularly among people with walking impairments
“for support and balance”, “when sitting down and
getting up”, “as the straps (on the overhead handrail)
were too high”, “handy if you had to travel standing”
and “good to hold on to if the bus were moving”.
Most of the participants including cane users
needed a handhold or stanchion when getting into
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and out of the forward-facing seats. Walker users,
however, relied on their walker for support when
getting into or out of the seat.
4. Discussion
Individuals with mobility impairments were found
to require longer time and reported greater difficulty
for some tasks including getting into a seat, moving
to a vacant seat, and getting to the exit door particu-
larly in more crowded conditions. The study also
showed the need for adequate device storage space
and the importance of support features like handrails
and vertical stanchions during ambulation and seat-
ing by people with mobility limitations. A detailed
analysis of the video and movement data is being
performed to more specifically characterize boarding
and alighting movement and behavior during the tri-
als.
Not all the designs considered in this study were
equally favored based on previous literature and
feedback from a few industry representatives, either
due to prevailing market trends (e.g. forward-facing
seats being more prevalent), limitations in existing
station infrastructure (e.g. difficulties with ramp de-
ployment and fare-payment in rear-boarding), and
costs (e.g. use of two folding ramps). However, pas-
senger concerns about inadequate stowage space for
non-wheelchair mobility aids such as walkers, canes,
other items carried with walking aids, and insuffi-
cient assistive design features like handholds and
stanchions can be overcome by making modest but
concerted changes to the bus interior.
In many of the low-floor buses that have forward
boarding, the priority seats for the elderly and mobil-
ity impaired are often located in the same area desig-
nated for wheelchairs. Further, these might be the
only side-facing seats on the bus that provide the
necessary legroom, causing the ambulant disabled
and wheeled mobility users to compete for the same
space. The legroom provided between forward-
facing seats was also commented as being inadequate
by many participants that had walking impairments.
During the study, the spacing between forward-
facing seats was set at 675 mm (26.5 in.) and meas-
ured at seat pan height from the seat back cushion to
the rear panel of the seat in front. This value repre-
sents the recommended industry-minimum [1] and
was also observed in field measurements – but in-
creasing the spacing is recommended.
Study participants were required to use a smart
card for fare payment, which consists of a program-
mable card to automatically pay the fare when
brought within a few inches of a sensing device or
card-reader. Participants reported significant ease in
using this system, decreasing payment time as well as
the anxiety of handling coins and producing exact
change. These systems are a significant improve-
ment over the typical magnetic strip cards in terms of
technology and usability [4] and have been intro-
duced in some larger cities like Los Angeles and
Washington, D.C.
The focus of this study was on the preferences that
ambulatory individuals with and without walking
aids had towards the physical configuration of the
bus environment. While the study did not simulate
the bus in movement, the use of the laboratory-based
environmental simulation provides the opportunity to
evaluate how new concept designs of transit vehicles
could impact user performance. Results clearly
demonstrate that design features in low-floor buses
can impact design preferences; particularly for those
who use walking aids. These results support the use
of ergonomics and inclusive design to improve the
design of future low-floor public transit buses.
Acknowledgements
This research was supported with funding pro-
vided by the U.S. Department of Education, National
Institute on Disability and Rehabilitation Research
(NIDRR) through the RERC on Accessible Public
Transportation (Grant# H133E080019). The opin-
ions expressed in this paper are those of the authors
and do not represent those of the Department of Edu-
cation or NIDRR.
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