RVAAC	Subcommittee	on	Circulation

Date March	25,	2014

To: Subcommittee	members

From: Ed	Steinfeld,	IDeA	Center

Re: Clear	floor	space	proposal

Introduction

Clear	floor	space	(CFS)	dimensions	are	the	basis	for	the	minimum	required	size	of	

spaces	used	by	wheeled	mobility	device	users	(e.g.	platform/wheelchair	lifts)	and	

for	seating	spaces/locations	that	are	designated	for	wheeled	mobility	users.	The	

clear	floor space	width	also	informs	the	minimum	clearance	width	for	successful	

passage	through	corridors,	doorways and	wheelchair	ramps.		

The	CFS	represents	the	space	required	for	an	occupied stationary	wheeled	mobility	

device (WMD).	This	area	is	typically	depicted	as	a	rectangular	space.	The	

dimensions	of	the	CFS	should	be	based	on	measurements	of	occupied	length	and	

occupied	breadth	of	wheeled	mobility	devices,	which	are	defined	as	follows:	

 Occupied	length:	measured	as	the	horizontal	distance	between	the	forwardmost	(anterior-most)	point	and the	rear-most	(posterior-most)	point	on the	

wheelchair	or	occupant.

 Occupied	width:	measured	as	the	horizontal	distance between	the	side-most	

(lateral-most)	points of	the	wheelchair	or	participant	on	the	right	and	left	

sides.

Minimum	dimensions	for	clear	floor	space	should	be	considered	as	a	starting	point	

for	accessible	design.		When	determining	the	clear	floor	space	for	tasks	that	involve	

reaching	or	grasping	to	adjacent	design	elements	other	space	needs	and	functional	

abilities	of	the	user	population	must	be	considered,	e.g.	the	position	of	the	CFS	with	

respect	to	the	reach	target	or	distance	from	the	CFS	to	the	target.	To	simplify	

decision	making, however,	decisions	on	the	size	of	the	CFS	should	be	made	first	so	

that	a	basis	for	addressing	the	other	issues	can	then	be	made	within	the	context	of	

the	CFS.

In	the	U.S.,	federal	accessibility	guidelines	prescribe	a	minimum	floor	area	of	30	

inches	wide	by	48	inches	long	for	wheeled	mobility	access.	Additional	space	of	6	

inches	in	width	and	12	in.	in	length	is	required	when	this	space	is	located	within	an	

alcove	(36	x	60).	
The	Center	for	Inclusive	Design	and	Environmental	Access	(IDeA)	at	the	University	

at	Buffalo	conducted	an	anthropometric	study	of	500	individuals	who	use	wheeled	

mobility	devices	(WMD).		The	research	included	the	collection	of	demographic	

information	and	WMD	characteristics,	and	the	measurement	of	structural	and	

functional	anthropometry.	Data	collection	included	3	dimensional	measurement	of	

approximately	90	points	located	on	the	body	and	device.	The	methods	used	to	

collect	the	information	have	been	reported	elsewhere	(e.g.,	Paquet	et	al.,	2004,	

D’Souza	et	al.,	2010;	Steinfeld	et	al.,	2010a;	2010b).	

Research	Results

Figure 1: Accommodation model on clear floor space for wheeled mobility users. Lengths and widths in 

inches are given in the parentheses. 
Data	on	occupied	floor	area	length	and	width	are	summarized	in	the	form	of	an	

“accommodation	model”	(Fig.	1)	that	depicts	the	50th,	75th,	90th	and	95th	

percentile	values	computed	for	occupied	length	and	width	across	manual	chair,	

powered	chair	and	scooter	users.	International	convention	requires	the	use	of	the	

metric	system	in	the	science	of	anthropometry.	So,	we	have	shown	imperial	

equivalents	in	parentheses.	The	results	suggest	that	a	width	of	32”	and	length	of	54”	

approximates	the	95th%tile	values	of	occupied	length	and	width	for	manual	chair	

users,	and	90th%tile	values	of	length	and	width	for	the	power	chair	and scooter	

users	(highlighted	in	red).	

In	vehicles,	tight	spaces	require	greater	tolerances,	similar	to	what	would	be	

required	in	alcoves,	to	position	wheelchairs	into	place	in	reserved	seating	areas	and	

in	securement	locations.	On	rail	vehicles,	securement	of	WMD	users	is	not	required	

for	two	reasons.	First,	it	is	not	required	of	other	passengers.	Second,	the	mass	of	rail	

vehicles	is	so	large	that	the	de-acceleration	forces	in	a	collision	are	not	as	severe	as	

with	motor	vehicles.	But,	on	long	distance	rail,	WMD	users	may	transfer	out	of	their	

device.	In	that	case,	the	device	should be	stowed	to	prevent	it	from	becoming	an	

obstacle	in	an	emergency	or	from	injuring	others	due	to	a	collision	or	sudden	

movement.	Stowage	spaces	do	not	have	to	be	as	large	as	the	CFS	because	the	devices	

are	unoccupied.	Note	that	scooters	and	power	chairs	cannot	be	folded	to	be	stowed.	

Research	on	rail	systems	also	demonstrates	that	many	large	items	are	brought	onto	

rail	systems,	including	things	like	baby	carriages,	bicycles,	lawnmowers	and	

plumbing	fixtures.	When	not	used	by	WMD	users,	reserved	spaces	can	be	useful	for	

keeping	these	objects	out	of	the	circulation	path.	Moreover,	flip	down	seats	can	be	

provided	that	can	be	used	to	eliminate	any	loss	of	capacity	when	WMD	users	are	not	

occupying	such	spaces.

In	some	rail	systems,	seating	is	longitudinal,	e.g.	along	the	outside	walls	facing		in;	in	

others	it	is	in	rows	facing	forward	or	both	forward	and	backward.	In	still	others,	

both	types	are	used.	In	special	cars,	like	dining	and	observation	cars,	table	seating	

may	be	provided.	WMD	users	should	have	equivalent	types	of	seating,	with	access	to	

equivalent	amenities	such	as	a	firm	table	top,	wherever	it	is	provided	in	an	

accessible	level	or	car.	Thus,	flexibility	is	needed	to	address	the	different	

possibilities.

Proposals

1. CFS	for	occupied	devices	shall	be	provided	immediately	inside	accessible	

entrances.	

2. An	accessible	path	of	travel	shall	be	provided	to	all	CFS.	

3. The	CFS	shall	not	be	located	in	vestibules	or	other	areas	where	seating	is	not	

provided	for	other	passengers,	although	an	accessible	path	of	travel	is	

needed	in	these	areas.	
4. The	CFS for	occupied	devices	shall be a	minimum	of 32	in.	x	54	in.	for	each	

device	accommodated unless	the	sides	of	the	CFS	are	bounded	by	immovable	

objects.

5. At	least	two	CFS	spaces	shall	be	provided	on	each	car.	They	can	be	grouped	

together	in	one	contiguous	space	or	separated	into	more	than	one	space.

6. An	additional	tolerance	of	6	in.	of	width	and	12	in.	of	depth	should	be	

provided	where	the	space	is	bounded.		Both	tolerances	are	needed	where	the	

space	is	bounded	on	three	sides	but	only	one	tolerance	(whichever	is	

appropriate)	if	the	space	is	only	bounded	on	two	sides.	

7. A	set	of	illustrations	is	needed	to	show	how	these	basic	tolerances	are	

applied	in	different	types	of	seating	arrangements.

8. Flip	down	seats	should	be	provided in	the	CFS to	use	by	ambulant	passengers

when	not	used	by	wheelchair	users.		

9. “Transfer	seats”	should	be	available	on	all	accessible	cars. The	number	

required	should	be	based	on	the	capacity	of	the	car	(to	be	determined).

10. Flip	down	seats	may	be	designated	as	transfer	seats,	in	which	case,	the	flip	

down	seat	cannot	protrude	into	the	CFS.

11. A	CFS	should	be	provided	next	to	all	transfer	seats.

12. The	stowage	space	for	unoccupied	devices	should	be	large	enough	for	

stowing	as	many	WMDs	as	there	are	seating	spaces	for	WMD	users	on	a	car.	

Minimum	dimensions	of	any	stowage	space	shall	be	??	x	??.	

Note:	Although	we	have	not	yet	analysed	our	data	for	unoccupied	devices,	we	

can	do	that	and	determine	the	overall	space	needed	for	power	chairs	and	

scooters.

13. Stowage	for	WMD	users	may	be	combined	with	stowage	space	for	other	

devices,	e.g.	bicycles,	strollers,	packages	and	other	objects.

Stowage	space	shall	be	separated	from	passenger	seating	by	partitions.