Regulation No. 52-01

Name:Regulation No. 52-01
Description:Small Capacity Public Service Vehicle Construction.
Official Title:Uniform Provisions Concerning the Approval of: M2 and M3 Small Capacity Vehicles with Regard to their General Construction.
Country:ECE - United Nations
Date of Issue:1983-01-18
Amendment Level:01 Series, Supplement 9
Number of Pages:59
Vehicle Types:Bus
Subject Categories:Electrical and Electronic, Miscellaneous, Occupant Protection, Masses and Dimensions
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Keywords:

vehicle, door, paragraph, seat, service, emergency, driver, approval, regulation, figure, passengers, area, doors, space, provided, annex, position, mass, means, step, case, passenger, height, access, seats, class, device, force, standing, fitted, width, type, surface, vehicles, requirements, vertical, window, number, closing, floor, minimum, aperture, compartment, total, dimensions, controls, side, maximum, requirement, part

Text Extract:

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E/ECE/324 )
E/ECE/TRANS/505 ) Rev.1/Add.51/Rev.3
February 15, 2008
STATUS OF UNITED NATIONS REGULATION
ECE 52-01
UNIFORM PROVISIONS CONCERNING THE APPROVAL OF:
M AND M SMALL CAPACITY VEHICLES WITH
REGARD TO THEIR GENERAL CONSTRUCTION
Incorporating:
01 series of amendments
Date of Entry into Force: 12.09.95
Supplement 1 to the 01 series of amendments
Date of Entry into Force: 03.01.98
Supplement 2 to the 01 series of amendments
Date of Entry into Force: 29.12.00
Supplement 3 to the 01 series of amendments
Date of Entry into Force: 21.02.02
Supplement 4 to the 01 series of amendments
Date of Entry into Force: 15.08.02
Supplement 5 to the 01 series of amendments
Date of Entry into Force: 07.12.02
Corr. 1 to Supplement 5 to the 01 series of amendments
Dated: 13.11.02
Supplement 6 to the 01 series of amendments
Date of Entry into Force: 12.08.04
Supplement 7 to the 01 series of amendments
Date of Entry into Force: 13.11.04
Supplement 8 to the 01 series of amendments
Date of Entry into Force: 09.11.05
Supplement 9 to the 01 series of amendments
Date of Entry into Force: 10.11.07

REGULATION NO. 52
UNIFORM PROVISIONS CONCERNING THE APPROVAL OF M AND M SMALL
CAPACITY VEHICLES WITH REGARD TO THEIR GENERAL CONSTRUCTION
CONTENTS
1. Scope
2. Definitions
3. Application for Approval
4. Approval
5. Specifications
6. Modification and Extension of Approval of a type of vehicle
7. Conformity of Production
8. Penalties for Non-conformity of Production
9. Production Definitely Discontinued
10. Transitional Provisions
11. Names and Addresses of Technical Services Responsible for Conducting Approval Tests,
and of Administrative Departments
ANNEXES
Annex 1

Communication Concerning the Approval or Extension or Refusal or Withdrawal of
Approval or Production Definitely Discontinued of a Vehicle Type with Regard to its
Structural Features, Pursuant to Regulation No. 52
Annex 2 – Arrangements of Approval Marks
Annex 3 – Explanatory Diagrams
Annex 4 – Guidelines for measuring the closing forces of power-operated doors

2.7. "Emergency Window" means a window, not necessarily glazed, intended for use as an
exit by passengers in an emergency only;
2.8. "Double Window" means an emergency window which, when divided into two by an
imaginary vertical line (or plane), exhibits two parts each of which complies as to
dimensions and access with the requirements applicable to a normal emergency window;
2.9. "Escape Hatch" means a roof-opening intended for use as an exit by passengers in an
emergency only;
2.10. "Emergency Exit" means an emergency door, emergency window or escape hatch;
2.11. "Exit" means a service door or emergency exit;
2.12. "Sliding Door" means a door, which can be opened or closed only by sliding it along one or
more rectilinear or approximately rectilinear rails;
2.13. "Floor" or "deck" means that part of the bodywork whose upper surface supports standing
passengers, the feet of seated passengers and of the driver, and seat mountings;
2.14. "Gangway" means the space providing access by passengers from any seat or row of
seats to any other seat or row of seats or to any access passage from or to any service
door; it does not include:
2.14.1. The space required to accommodate the feet of seated passengers;
2.14.2. The space above the surface of any step or staircase; or
2.14.3. Any space which affords access solely to one seat or to one row of seats.
2.15. "Access Passage" means the space extending inwards into the vehicle from the service
door up to the outermost edge of the upper step (edge of the gangway). Where there is no
step at the door, the space to be considered as access passage shall be that which is
measured according to Paragraph 5.7.1.1. up to a distance of 30 cm from the starting
position of the inner face of the dual panel.
2.16. "Driver's Compartment" means the space intended for the driver's exclusive use, except
in emergency, and containing the steering wheel, controls, instruments and other devices
necessary for driving the vehicle;
2.17. "Unladen Kerb Mass" (MK) (kg) means the mass of the vehicle in running order,
unoccupied and unladen but with the addition of 75 kg for the mass of the driver, the mass
of fuel corresponding to 90% of the capacity of the fuel tank specified by the manufacturer,
and the masses of coolant, lubricant, tools and spare wheel, if any;
2.17.1. "Unladen Mass" (MV) (kg) means the unladen kerb mass (MK) (kg) of the vehicle as
defined in Paragraph 2.17., with the addition of 75 kg for the mass of the crew member
corresponding to the seat, if any, specially assigned to this crew member as described in
Paragraph 5.7.1.8. The vehicle shall be complete with 90% of the capacity of all additional
liquid tanks (e.g. fuel for combustion heaters, screen washers, etc.). Where facilities such
as a kitchen or toilet are fitted, the fresh water tanks shall be full and the waste tanks empty.

3.2. It shall be accompanied by the undermentioned documents in triplicate and by the following
particulars:
3.2.1. A detailed description of the vehicle type with respect to its structure, dimensions,
configuration and constituent materials;
3.2.2. Drawings of the vehicle and its interior arrangements; and
3.2.3. Particulars of
3.2.3.1. The technical maximum mass (MT) (kg);
3.2.3.2. The technical maximum load for each axle (kg);
3.2.3.3. The unladen mass of the vehicle (MV) (kg);
3.2.4. Provision made, if any, for the carriage of baggage or goods;
3.2.5. Where one or more baggage compartments have been provided for baggage other than
hand baggage, the total volume of such compartments (V) (m ) and the total mass of the
baggage that they can obtain (B) (kg);
3.2.6. Where the vehicle is equipped to carry baggage on the roof, the total surface area available
for such baggage (VX) (m ) and the total mass of baggage that can be placed on it (BX)
(kg);
3.2.7. The horizontal projection of the total surface area intended for seated and standing
passengers (S ) (m );
3.2.8. The horizontal projection of the total surface area intended for standing passengers (S )
(m ) in accordance with Paragraph 5.2.;
3.2.9. The number of seating places intended for use by passengers and crew (if any). Sleeping
places and other accommodations which are intended to be temporarily used instead of a
seating place shall not count as seating places.
3.2.10. The intended total number of passengers (N);
3.2.11. The Class (A or B) for which the approval is requested.
3.3. A vehicle representative of the type to be approved shall be submitted to the technical
service responsible for conducting the approval tests.
4. APPROVAL
4.1. If the vehicle submitted for approval pursuant to this Regulation meets the requirements of
Paragraph 5 below, approval of that vehicle type shall be granted.
4.2. An approval number shall be assigned to each type approved. Its first two digits (at
present 01 corresponding to the 01 series of amendments which entered into force on
September 12, 1995) shall indicate the series of amendments incorporating the most recent
major technical amendments made to the Regulation at the time of issue of the
approval. The same Contracting Party shall not assign the same number to another vehicle
type.

5.1.1.2. Laden, as specified in Paragraph 5.1.4.
5.1.2. The front axle (or axles) shall carry not less than the percentage of mass shown in the table
below:
Loading Conditions Class A Class B
Unladen 20 25
Laden 25 25
5.1.3. Unladen, for the purpose of this Paragraph (5.1.) and Paragraph 5.3., means the vehicle in
the condition described in Paragraph 2.17.1.
5.1.4. Laden, for the purpose of this Paragraph (5.1.), means the vehicle unladen as described in
Paragraph 5.1.3. with the addition of a mass Q on each passenger seat, a number,
corresponding to the authorized number of standing passengers, of mass Q uniformly
distributed over the area S , a mass equal to B uniformly distributed in the baggage
compartments and, where appropriate, a mass equal to BX uniformly distributed over the
surface area of the roof equipped for the carriage of baggage (MT) (kg).
5.1.5. The values of Q for the different classes of vehicles are specified in Paragraph 5.3.2.
5.1.6. B (kg) shall have a numerical value not less than 100 V (m ).
5.1.7. BX shall exert a pressure of not less than 75 kg/m over the whole surface area of the roof
equipped for the carriage of baggage.
5.2. Area Available for Passengers
5.2.1. The total surface area S available for passengers is calculated by deducting from the total
area of the vehicle:
5.2.1.1. The area of the driver's compartment;
5.2.1.2. The area of steps at doors and the area of any step with a depth of less than 30 cm;
5.2.1.3. The area of any part over which the vertical clearance is less than 135 cm measured from
the floor, according to Paragraph 5.7.8. and disregarding instructions permitted. In the case
of vehicles to which Paragraph 5.7.1.9. applies, this dimension may be reduced to 120 cm.
5.2.2. The surface area S available for standing passengers (only in the case of Class A vehicles)
is calculated by deducting from S :
5.2.2.1. The area of all parts of the floor in which the slope exceeds 8%;
5.2.2.2. The area of all parts which are not accessible to a standing passenger when all the seats
are occupied, with the exception of folding seats;
5.2.2.3. The area of all parts where the clear height above the floor is less than 190 cm or in the
case of the section of the gangway situated above and behind the rear axle, and the
attaching parts thereof - less than 180 cm (handholds shall not be taken into account in this
connection);

5.3.2.1. In vehicles of Class B, S = 0.
5.3.2.2. The values of Q, S , L and R for both classes of vehicles are as follows:
Class Q (kg) S (m /standing passenger)
L
(kg/m )
R
(kg/m )
A 68 0,125 100 75
B 71 (no standing passengers) 100 75
Including 3 kg of hand baggage.
5.3.2.3. If a vehicle of Class B is approved as a Class A vehicle, the mass of baggage carried in the
baggage compartments accessible only from outside the vehicle is not taken into account.
5.3.3. When calculated according to Paragraph 5.3.2., the mass on each axle of the vehicle shall
not exceed the values of their respective technically permissible maximum values.
5.3.4. The vehicle shall be clearly marked in a manner visible on the inside in the vicinity of the
front door in letters or pictograms not less than 15 mm high and numbers not less than
25 mm high, with
5.3.4.1. The number of seating places for which the vehicle is designed (P );
5.3.4.2. The total number of passengers for which the vehicle is designed (N);
5.3.4.3. The number of wheelchairs, if any, for which the vehicle is designed.
5.4. Strength of the Superstructure
In the case of Class B vehicles only, it must be shown by calculation or by any other suitable
method that the structure of the vehicle is strong enough to withstand an evenly-distributed
static load on the roof equal to the technical maximum mass (MT) of the vehicle.
5.5. Protection Against Fire Risks
5.5.1. Engine Compartment
5.5.1.1. No inflammable sound-proofing material or material liable to become impregnated with fuel
or lubricant shall be used in the engine compartment unless the material is covered by an
impermeable sheet.
5.5.1.2. Precautions shall be taken, either by a suitable layout of the engine compartment or by the
provision of drainage orifices, to avoid so far as possible the accumulation of fuel or
lubricating oil in any part of the engine compartment.

5.5.4. Fuel-feed Systems
5.5.4.1. No apparatus used for the fuel feed shall be placed in the driver's compartment or the
passenger compartment.
5.5.4.2. Fuel lines and all other parts of the fuel-feed system shall be accommodated in positions on
the vehicle where they have the fullest reasonable protection.
5.5.4.3. Twisting or bending movements and vibration of the vehicle structure or the power unit shall
not subject the fuel lines to abnormal stress.
5.5.4.4. The unions of pliable or flexible pipes with rigid parts of the fuel-feed system shall be so
designed and constructed as to remain leakproof in the various conditions of use of the
vehicle, despite ageing, twisting or bending movements, or vibration of the vehicle structure
or the power unit.
5.5.4.5. Fuel leaking from any part of the system shall be able to flow away freely to the road
surface, but never onto the exhaust system.
5.5.5. Emergency Switch, if Fitted
If an emergency switch is fitted to reduce the risk of fire after the vehicle has come to a
standstill, this emergency switch shall have the following characteristics:
5.5.5.1. It shall be located within immediate reach of the driver seated in the driver's seat;
5.5.5.2. It shall be clearly marked and be provided with a protective cover or other suitable means to
prevent inadvertent operation. Clear instructions concerning the method of operation shall
be displayed in the immediate vicinity of the emergency switch, e.g. "Remove cover and
move lever downwards! Actuate only when the vehicle has been brought to a stop";
5.5.5.3. Its actuation shall cause simultaneous performance of the following functions:
5.5.5.3.1. Quick stoppage of the engine;
5.5.5.3.2. Operation of a battery isolating switch, fitted as close to the batteries as possible, and which
isolates at least one battery terminal from the electrical circuit, with the exception of the
circuit permitting the function required by Paragraph 5.5.5.3.3. below, the circuits which
ensure the uninterrupted function of the tachograph as well as those devices whose sudden
removal from service could provoke a greater risk than the one avoided, for example:
5.5.5.3.2.1. Emergency interior lighting;
5.5.5.3.2.2. Cooling scavenger of auxiliary heaters;
5.5.5.3.2.3. Centralized electronic door locking.
5.5.5.3.3. Switching-on of the vehicle's hazard warning signal.
5.5.5.4. Performance of the functions mentioned in Paragraph 5.5.5.3. above may be initiated not
only by the emergency switch, but also by separate controls, provided that these do not in
an emergency interfere with the functioning of the emergency switch.

5.6.1.2. For the purpose of this requirement, service doors equipped with a power-operated control
system shall not be deemed to be exits unless they can be readily opened by hand once the
control prescribed in Paragraph 5.6.5.1. has been actuated, if necessary.
5.6.1.3. The minimum number of emergency exits shall be such that the total number of exits and of
escape hatches is as follows:
Number of
passengers
Minimum number
of exits
Number of escape hatches
counted as emergency exits
permitted
Required
≤ 16 3 1
> 16 4 1
5.6.1.4. Where the driver's compartment does not communicate with the inside of the vehicle it shall
have two exits, which shall not both be in the same lateral walls; where one of the exits is a
window it shall comply with the requirements set out in Paragraphs 5.6.3.1., 5.6.8.1. and
5.6.8.2. for emergency windows.
5.6.1.5. A double service door shall count as two doors and a double window as two emergency
windows.
5.6.2. Siting of Exits
5.6.2.1. The service door(s) shall be situated on the side of the vehicle that is nearer to the side of
the road corresponding to the direction of traffic, or in the rear face of the vehicle.
5.6.2.2. The exits shall be placed in such a way that there is at least one exit on each side of the
vehicle.
5.6.2.3. The forward half and the rearward half of the passenger space shall each contain at least
one exit.
5.6.2.4. At least one exit shall be situated either in the rear face or in the front face of the vehicle
unless an escape hatch is fitted in the roof.
5.6.2.5 If the space reserved for the driver's seat and the passengers' seats beside the driver's seat
does not communicate with the main passengers' compartment by means of a suitable
passageway.
5.6.2.5.1. The main compartment reserved for passengers shall contain exits satisfying the
requirement of Paragraph 5.6.1. with respect to number and those of Paragraphs 5.6.2.1.,
5.6.2.2. and 5.6.2.3. above with respect to siting;

5.6.3.2. A vehicle to which Paragraph 5.7.1.9. applies shall meet the requirements of
Paragraph 5.6.3.1. above in respect of emergency windows and escape hatches, and the
following requirements in respect of service doors and emergency doors:
Aperture Dimensions Remarks
Service
door
Emergency
door
Aperture height:
110 cm
Width:
Single door: 65
cm
Double door:
120 cm
Height: 110 cm
Width: 55 cm
This dimension may be reduced by a radius at the corners of the aperture not
exceeding 15 cm radius.
This dimension may be reduced by a radius at the corners of the aperture not
exceeding 15 cm radius.
The width may be reduced by 10 cm when the measurement is made at the level
of the hand-holds and by 25 cm in cases where intruding wheel arches or the
actuating mechanism for automatic or remote-control doors or the rake of the
windscreen so require.
The width may be reduced to 30 cm in cases where intruding wheel arches so
require, providing that the width of 55 cm is respected at the minimum height of
40 cm above the lowest part of the door aperture. The height and width at the
upper corners may be reduced with round-offs, with a radius of not more than
15 cm.
5.6.4. Technical Conditions for all the Service Doors
5.6.4.1. Every service door shall be capable of being easily opened from inside and from outside the
vehicle when the vehicle is stationary (but not necessarily when the vehicle is moving).
However, this requirement shall not be construed as precluding the possibility of locking the
door from outside, provided that the door can always be opened from inside.
5.6.4.2. Every control or device for opening a service door from the outside shall not be more than
180 cm above the ground when the vehicle is standing unladen on a level surface.
5.6.4.3. Every one-piece manually-operated service door which is hinged or pivoted shall be so
hinged or pivoted that if the open door comes into contact with a stationary object while the
vehicle is moving forwards it tends to close.
5.6.4.4. If a manually-operated service door is fitted with a slam lock it shall be of the two-stage type.
5.6.4.5. On the inside of a service door there shall not be any device intended to cover the inside
steps when the door is closed.
5.6.4.6. If the direct view is not adequate, optical or other devices shall be installed to enable the
driver to detect from his seat the presence of a passenger in the immediate interior and
exterior vicinity of every service door which is not an automatically-operated service door.
5.6.4.7. Every door which opens towards the interior of the vehicle shall be so constructed that its
movement is not likely to cause injury to passengers in normal conditions of use. Where
necessary, appropriate protection devices shall be fitted.
5.6.4.8. If a service door is located adjacent to a toilet door or a door to another internal
compartment the service door shall be proofed against an unintentional
operation. However, this requirement shall not apply if the service door is locked
automatically when the vehicle is moving at a speed exceeding 5 km/h.

5.6.5.4. Every power-operated service door shall activate a visual tell-tale, which shall be plainly
visible to the driver when seated in the normal driving position in any ambient lighting
condition, to warn that a door is not fully closed. This tell-tale shall signal whenever the rigid
structure of the door is between the fully open position and a point 30 mm from the fully
closed position. One tell-tale may serve for one or more doors. However, no such tell-tale
shall be fitted in respect of a front service door which does not comply with the requirements
of Paragraphs 5.6.5.6.2. and 5.6.5.6.3.
5.6.5.5. Where controls are provided for the driver to open and close a power-operated service door,
they shall be such that the driver is able to reverse the movement of the door at any time
during the closing or opening process.
5.6.5.6. The construction and control system of every power-operated service door shall be such
that a passenger is unlikely to be injured by the door or trapped in the door as it closes.
5.6.5.6.1. Except in the case of the front service door, this requirement shall be considered satisfied if
the following two requirements are met:
5.6.5.6.2. The first requirement is that when the closing of the door at any measuring point described
in Annex 4 to this Regulation is resisted by a clamping force not exceeding 150 N, the door
shall reopen automatically to its fullest extent and, except in the case of an
automatically-operated service door, remain open until a closing control is operated. The
clamping force may be measured by any method to the satisfaction of the competent
authority. Guidelines are given in Annex 4 to this Regulation. The peak force may be
higher than 150 N for a short time provided that it does not exceed 300 N. The reopening
system may be checked by means of a test bar having a section of height 60 mm, width
30 mm with corners radiused to 5 mm.
5.6.5.6.3. The second requirement is that whenever the doors are closed onto the wrist or fingers of a
passenger:
5.6.5.6.3.1. The door reopens automatically to its fullest extent and, except in the case of an
automatically-operated service door, remains open until a closing control is operated, or
5.6.5.6.3.2. The wrist or fingers can be readily extracted from the doors without risk of injury to the
passenger. This requirement may be checked by hand, or by means of the test bar
mentioned in Paragraph 5.6.5.6.2., tapered at one end over a length of 300 mm from a
thickness of 30 mm to a thickness of 5 mm. It shall not be treated with polish nor lubricated.
If the door traps the bar it shall be capable of being easily removed, or
5.6.5.6.3.3. The door is maintained at a position allowing the free passage of a test bar having a section
of height 60 mm, width 20 mm with corners radiused to 5 mm. This position shall not be
more than 30 mm distant from the fully closed position.
5.6.5.6.4. In the case of a front service door the requirement of Paragraph 5.6.5.6. shall be considered
satisfied if the door:
5.6.5.6.4.1. Fulfils the requirements of Paragraphs 5.6.5.6.2. and 5.6.5.6.3., or
5.6.5.6.4.2. Is fitted with soft edges; these shall not, however be so soft that if the doors are closed onto
the test bar mentioned in Paragraph 5.6.5.6.2. the rigid structure of the doors will reach the
fully closed position.

5.6.6.3.2. If a passenger enters or leaves the vehicle while the door is closing, the closing process
shall be interrupted automatically and the door shall return to the open position. The
reversal may be actuated by one of the devices referred to in Paragraph 5.6.6.3.1. or by any
other device.
5.6.6.3.3. A door that has closed automatically in accordance with Paragraph 5.6.6.3.1. shall be
capable of being opened again by a passenger in accordance with Paragraph 5.6.6.2.; this
shall not apply if the driver has deactivated the opening controls.
5.6.6.3.4. After deactivation of the opening controls of the automatically-operated service doors by the
driver, open doors shall close in accordance with Paragraphs 5.6.6.3.1. to 5.6.6.3.3.
5.6.6.4. Inhibition of the automatic closing process on doors marked for special service, e.g. for
passengers with prams, disabled persons, etc.
5.6.6.4.1. The driver shall be able to inhibit the automatic closing process by actuation of a special
control. A passenger shall also be able to inhibit the automatic closing process directly by
pressing a special push button.
5.6.6.4.2. The inhibition of the automatic closing process shall be indicated to the driver e.g. by a
visual tell-tale.
5.6.6.4.3. The cancellation of the reversing of the automatic closing process shall be capable of being
done only by the driver.
5.6.6.4.4. Paragraph 5.6.6.3. shall apply to the subsequent closing of the door.
5.6.7. Technical Requirements for Emergency Doors
5.6.7.1. Emergency doors shall be capable of being easily opened from inside and from outside
when the vehicle is stationary. However, this requirement shall not be construed as
precluding the possibility of locking the door from the outside, provided that the door can
always be opened from the inside by the use of the normal opening mechanism.
5.6.7.2. Emergency doors shall not be fitted with a power-operated system or be of the sliding type.
If a sliding door has been shown to be capable of being opened without the use of tools
after a frontal barrier collision test, in accordance with Regulation No. 33, it can be accepted
as an emergency door.
5.6.7.3. The outside handles of emergency doors shall be not more than 180 cm from the ground
when the vehicle is standing unladen on level ground.
5.6.7.4. Hinged emergency doors fitted to the side of the vehicle shall be hinged at their forward
edge and shall open outwards. Check straps, chains or other restraining devices shall be
permitted, provided that they do not prevent the door from opening to and remaining open at
an angle of at least 100°. If a means is provided sufficient to give free passage to the
emergency door access gauge, the 100° minimum angle requirement shall not apply.
5.6.7.5. If an emergency door is located adjacent to a toilet door or a door to another internal
compartment the emergency door shall be protected against unintentional
operation. However, this requirement shall not apply if the emergency door is locked
automatically when the vehicle is moving at a speed exceeding 5 km/h.

5.6.10. Retractable Steps
Retractable steps, if fitted, shall comply with the following requirements:
5.6.10.1. If power operated, their operation shall be synchronized with that of the corresponding
service or emergency door;
5.6.10.2. When the door is closed no part of the retractable step shall project more than 10 mm
beyond the adjacent line of the bodywork;
5.6.10.3. When the door is open and the retractable step is in the extended position, the surface area
shall conform to the requirements of Paragraph 5.7.7. of this Regulation.
5.6.10.4. In the case of the power operated step it shall not be possible for the vehicle to move from
rest, under its own power, when the step is in the extended position. In the case of a
manually operated step, an audible or visual indication shall alert the driver when the step is
not fully retracted;
5.6.10.5. The step shall not be capable of being extended when the vehicle is in motion. If the device
to operate the power operated step fails, the step shall retract and remain in the retracted
position. However, the operation of the corresponding door shall not be hindered in the
event of such a failure, or if the step is damaged;
5.6.10.6. When a passenger is standing on the power operated retractable step, the corresponding
door shall be incapable of being closed. Compliance with this requirement shall be checked
by placing a mass of 15 kg, representing a small child, in the centre of the step. This
requirement shall not apply to any door within the driver's direct field of view;
5.6.10.7. The movement of the retractable step shall not be liable to cause any bodily harm either to
passengers or to persons waiting at bus stops;
5.6.10.8. The corners of retractable steps facing forwards or rearwards shall be rounded to a radius of
not less than 5 mm, the edges shall be rounded to a radius of not less than 2.5 mm;
5.6.10.9. When the passenger door is opened, the retractable step shall be securely held in the
extended position. When a mass of 136 kg is placed in the centre of a single step or a
mass of 272 kg is placed in the centre of a double step the deflection at any point on the
step, measured relative to the body of vehicle, shall not exceed 10 mm.
5.6.11. Markings
5.6.11.1. Each emergency exit shall be marked by an inscription reading "Emergency exit" inside and
outside the vehicle.
5.6.11.2. The emergency controls of service doors and of all emergency exits shall be marked as
such inside and outside the vehicle either by a representative symbol or by a clearly-worded
inscription.
5.6.11.3. Clear instructions concerning the method of operation shall be placed on or close to every
emergency control of an exit.
5.6.11.4. The language in which the markings referred to in Paragraphs 5.6.11.1. to 5.6.11.3. above
are to be inscribed shall be determined by the competent administrative department of the
country of registration of the vehicle.

5.7.1.8. However, a folding seat for use by the crew may obstruct the access passage to a service
door when in the position of use provided that:
5.7.1.8.1. It is clearly indicated, both in the vehicle itself and on the communication form (Annex 1),
that the seat is for the use of crew only;
5.7.1.8.2. When the seat is not in use it folds automatically as necessary to comply with the
requirements of Paragraphs 5.7.1.1. or 5.7.1.2. and 5.7.1.3. to 5.7.1.5.;
5.7.1.8.3. The door is not considered to be a mandatory exit for the purpose of Paragraph 5.6.1.3.;
5.7.1.8.4. The seat is fitted with a retractable safety-belt; and
5.7.1.8.5. When the seat is in the position of use, and when it is in the folded position, no part of it
shall be forward of a vertical plane passing through the centre of the seating surface of the
driver's seat in its rearmost position and through the centre of the exterior rear-view mirror
mounted on the opposite side of the vehicle.
5.7.1.9. The service door and emergency door dimensions in Paragraph 5.6.3.1. and the
requirements of Paragraphs 5.7.1.1. to 5.7.1.7., 5.7.2.1. to 5.7.2.3., 5.7.5.1. and 5.7.8.5.
shall not apply to a vehicle of Class B with a mass not exceeding 3.5 t and up to
12 passenger seats in which each seat has unobstructed access to at least two doors.
5.7.1.10. A doorway and the route by which passengers gain access to it shall be considered
unobstructed if they have:
5.7.1.10.1. Measured parallel with the longitudinal axis of the vehicle, there is a clearance of not less
than 22 cm at any point and 55 cm at any point being more than 50 cm above the floor or
steps (Annex 3, Figure 19);
5.7.1.10.2. Measured perpendicular to the longitudinal axis of the vehicle, there is a clearance of not
less than 30 cm at any point and 55 cm at any point being more than 120 cm above the floor
or steps or less than 30 cm below the ceiling (Annex 3, Figure 20).
5.7.1.11. Gangways and access passages shall be covered with an anti-slip material.
5.7.1.12. The maximum slope of the floor in the access passage shall not exceed 5%.
5.7.2. Access to Emergency Doors (See Annex 3, Figure 2)
5.7.2.1. The free space between the gangway and the emergency door aperture shall permit the
free passage of a vertical cylinder 30 cm in diameter and 70 cm high from the floor and
supporting a second vertical cylinder 55 cm in diameter, the aggregate height of the
assembly being 140 cm.
5.7.2.2. The base of the first cylinder shall be within the projection of the second cylinder.
5.7.2.3. Where folding seats are installed alongside this passage, the free space for the cylinder
shall be required to be determined with the seat in the opened position.
5.7.2.4. For the driver's door to be accepted as an emergency door for the main passengers'
compartment, it shall:
5.7.2.4.1. Either satisfy all the requirements as to dimensions of the door aperture and accessibility, or

5.7.4.2. When the structural thickness of the roof is more than 150 mm, the smaller section of the
pyramid shall contact the aperture area of the escape hatch at the level of the outside
surface of the roof.
5.7.5. Gangways (See Annex 3, Figure 3)
5.7.5.1. The gangway of a vehicle shall be so designed and constructed as to permit the free
passage of a gauging device consisting of two coaxial cylinders with an inverted truncated
cone interposed between them, the gauging device having the following dimensions (in cm):
Lower Cylinder
Upper Cylinder
Class A
Class B
Diameter 35 30
Height 90 90
Diameter 55 45
Height 50 (40) 30
Overall Height 190 (180) 150
The gauging device may come into contact with strap hangers if fitted, and move them
away.
5.7.5.1.1. On vehicles of Class A, the diameter of the lower cylinder may be reduced from 35 cm to
30 cm in any part of the gangway which is located to the rear of the most forward of the
following two planes:
5.7.5.1.1.1. A transverse vertical plane situated 1.5 m forward of the centreline of the rear axle (foremost
rear axle in the case of vehicles with more than one rear axle);

5.7.8. Passenger Seats (Including Folding Seats) and Space for Seated Passengers
5.7.8.1. Over each seating position and, except in the case of the seat(s) alongside the driver, its
associated foot space, there shall be measured a free space with a height of not less than
90 cm, measured from the highest point of the uncompressed seat cushion and at least
135 cm from the mean level of the floor in the foot space. In the case of vehicles to which
Paragraph 5.7.1.9. applies, and also for seat(s) alongside the driver, these dimensions may
be reduced to 120 cm, measured from the floor and 80 cm measured from the highest point
of the uncompressed seat cushion.
5.7.8.1.1. This clear space shall extend over the whole horizontal area defined below:
5.7.8.1.1.1. The rectangular area of 40 cm in width, symmetrical in relation to the median vertical plane
of the seat, and having a length "L" defined in Figure 5, Annex 3, which represents a section
through the median vertical plane of the seat;
5.7.8.1.1.2. The area intended for the feet of the seated passenger, over the same width of 40 cm and a
depth of 30 cm.
5.7.8.1.2. However, this space shall not include, in its upper part adjacent to the wall of the vehicle, a
rectangular area 15 cm in height and 10 cm in width (See Annex 3, Figure 6).
5.7.8.1.3. In the space extending above the area mentioned in Paragraph 5.7.8.1.1.2. the following
intrusions shall be permitted:
5.7.8.1.3.1. Intrusion of the back of another seat;
5.7.8.1.3.2. Intrusion of a structural member provided that the intrusion is included within a triangle whose
peak is situated 70 cm from the top and whose base 10 cm in width and situated in the upper
part of the space in question, adjacent to the side wall of the vehicle (see Annex 3, Figure 7);
5.7.8.1.3.3. Intrusion situated in the lower part of the space in question, adjacent to the sidewall of the
vehicle, of a cross-sectional area not exceeding 200 cm and having a maximum width of
10 cm (Annex 3, Figure 8).
5.7.8.1.3.4. Intrusion of a wheel arch provided that one of the following two conditions is fulfilled:
5.7.8.1.3.4.1. The intrusion does not extend beyond the vertical centreline of the seat (Annex 3, Figure 9), or
5.7.8.1.3.4.2. The area 30 cm in depth available for the feet of the seated passenger is advanced by not
more than 20 cm from the edge of the seat cushion and not more than 60 cm in front of
the squab of the seat (Annex 3, Figure 10), these measurements being made in the
median vertical plane of the seat.
5.7.8.1.3.5. In the case of the seats of the first row, intrusion of the instrument panel in the limit of
10 cm and only at heights from the floor greater than 65 cm.
5.7.8.1.3.6. Intrusion of hopper type windows when open and their fittings.
5.7.8.1.4. In the case of the two rear side seating places, the rear edge adjacent to the side wall of
the vehicle of the space situated above the area mentioned in Paragraph 5.7.8.1.1.1. may
be replaced by a cylindrical segment 15 cm in radius (Annex 3, Figure 11).

5.7.8.5. Space for seated passengers (See Annex 3, Figure 16)
5.7.8.5.1. For a seat behind a partition or other rigid structure other than a seat, a minimum clear
space in front of each passenger seat shall be provided as shown in Annex 3, Figure 16. A
partition whose contour corresponds approximately to that of the inclined seat back may
intrude into this space as provided by Paragraph 5.7.8.4. Intrusion of the dashboard,
instrument panel, windscreen, sun visor, seat belts anchorages shall be allowed.
5.7.8.5.2. For a seat behind a seat and/or a seat facing the gangway, a minimum clear foot space of at
least 300 mm depth and a width according to Paragraph 5.7.8.2.1. shall be provided as
shown in Annex 3, Figure 15b. The local presence in this space of seat legs and of
intrusions as provided by Paragraphs 5.7.8.1.3.3. and 5.7.8.1.3.4. shall be permitted
provided that adequate space remains for the passengers' feet. This foot space may partly
be situated in and/or above the gangway but shall not create any obstruction when
measuring the minimum gangway-width in accordance with Paragraph 5.7.5. Intrusion of
the seat belts and seat belt anchorages shall be allowed.
5.7.8.5.3. However, at least two forward or rearward facing seats specifically intended and marked for
disabled passengers shall be provided in that part of the vehicle which is most suitable for
boarding. These seats shall be designed for the disabled so as to provide enough space,
shall have suitably designed and placed handholds to facilitate entry and exit of the seat and
provide communication from the seated position with the driver if necessary.
5.8. Artificial Interior Lighting
5.8.1. Internal Electrical Lighting shall be Provided for the Illumination of:
5.8.1.1. the passenger compartment;
5.8.1.2. any step or steps;
5.8.1.3. the access to any exits;
5.8.1.4. the internal markings and internal controls of all exits;
5.8.1.5. all places where there are obstacles.
5.9. Handrails and Handholds
5.9.1. General Requirements
5.9.1.1. Handrails and handholds shall be of adequate strength.
5.9.1.2. They shall be so designed and installed as to present no risk of injury to passengers.
5.9.1.3. Handrails and handholds shall be of a section enabling passengers to grasp them easily
and firmly. Every handrail shall provide a length of at least 10 cm to accommodate a hand.
No dimension of the section shall be smaller than 2 cm or greater than 4.5 cm except in the
case of handrails on doors and seats and in the case of a vehicle of Class B, in access
passages. In these cases handrails having a minimum dimension of 1.5 cm shall be
permitted provided that one other dimension is of at least 2.5 cm.

5.10. Guarding of Stepwells
5.10.1. Where any seated passenger is likely to be thrown forward into a stepwell as a result of
heavy braking, either a guard or a safety-belt shall be fitted. Where a guard is provided, it
shall have a minimum height from the floor on which the passenger's feet rest of 80 cm and
shall extend inwards from the wall of the vehicle at least as far as 10 cm beyond the
longitudinal centre line of any seating position where the passenger is at risk or to the riser
of the innermost step; whichever is the lesser dimension.
5.11. Luggage Racks, if Fitted, Driver Protection
5.11.1. The driver shall be protected from objects liable to fall from luggage racks in the case of
heavy braking.
5.12. Trap Doors, if Fitted
5.12.1. Every trap door in the floor of a vehicle shall be so fitted and secured that it cannot be
dislodged or opened without the use of tools or keys and no lifting or securing device shall
project by more than 8 mm above floor level. Edges of projections shall be rounded.
5.13. Reversing Lights
5.13.1. All vehicles having a service door in their rear face shall be equipped with reversing lights,
the installation of which must conform to the provisions of Regulation No. 48.
6. MODIFICATION AND EXTENSION OF APPROVAL OF A TYPE OF VEHICLE
6.1. Every modification of the vehicle type shall be notified to the administrative department
which approved the vehicle type. That department may then either:
6.1.1. Consider that the modifications made are unlikely to have an appreciable adverse effect and
that, in any case, the vehicle still meets the requirements; or
6.1.2. Require a further test report from the technical service responsible for conducting the tests.
6.2. Confirmation or refusal of approval, specifying the modifications, shall be communicated by
the procedure specified in Paragraph 4.3. above to the Contracting Parties to the
Agreement which apply this Regulation.
6.3. The competent authority issuing the extension of approval shall assign a series number for
such an extension and inform thereof the other Parties to the 1958 Agreement applying this
Regulation by means of a communication form conforming to the model in Annex 1 to this
Regulation.
7. CONFORMITY OF PRODUCTION
7.1. Every vehicle bearing an approval mark as prescribed under this Regulation shall conform
to the vehicle type approved.
7.2. In order to verify conformity as prescribed in Paragraph 7.1. above, a sufficient number of
random checks shall be made on serially-manufactured vehicles bearing the approval mark
required by this Regulation.

ANNEX 1
(Maximum format: A4 (210 × 297 mm))
COMMUNICATION
Issued by:
Name of administration:
.............................................
.............................................
.............................................
concerning:
APPROVAL GRANTED
APPROVAL EXTENDED
APPROVAL REFUSED
APPROVAL WITHDRAWN
PRODUCTION DEFINITELY DISCONTINUED
of a vehicle type Class A/Class B
Regulation No. 52.
with regard to its general construction, pursuant to
Approval No................................................... Extension No.: ...............................
1. Trade name or mark of the power-driven vehicle: ....................................................................
2. Vehicle type: ..............................................................................................................................
3. Name and address of applicant for approval: ...........................................................................
4. If applicable, name and address of representative of applicant for approval: ..........................
...................................................................................................................................................
5. Brief description of the vehicle type as regards its structure, dimensions, configuration and
constituent materials: ................................................................................................................
...................................................................................................................................................
6. Technical maximum mass of vehicle when tested (kg):
6.1. front axle load (kg): ...................................................................................................................
6.2. rear axle load (kg): ....................................................................................................................
6.3. total (MT) (kg): ...........................................................................................................................
7. Unladen mass (MV): .......................................................................................................... (kg)

18. Place: ........................................................................................................................................
19. Date: ..........................................................................................................................................
20. Signature: ..................................................................................................................................
21. The list of documents filed with the administration service which has granted approval and
available on request is annexed to this communication.

ANNEX 3
EXPLANATORY DIAGRAMS
Figure 1
Access to Service Doors
(See Paragraph 5.7.1.)

Dimensions in cm
Figure 3
Gangways
(See Paragraph 5.7.5.)
Dimensions (cm) ∅ A B ∅ C H
Class A 35 50 (40) 55 190 (180)
Class B 30 30 45 150

Figure 5
Length of Prescribed Seat Area
(See Paragraph 5.7.8.1.1.1.)

Figure 7
Figure 8
Permitted Intrusion of a
Permitted Intrusion in
Structural Member
Lower Part of Passenger Space
(See Paragraph 5.7.8.1.3.2.)
(See Paragraph 5.7.8.1.3.3.)
1 (cm) min
40 − 50
(35 cm at wheel arches and
engine compartment)

Figure 10
Permitted Intrusion of a Wheel Arch Extending Beyond the Vertical
Centreline of the Side Seat
(See Paragraph 5.7.8.1.3.4.)

Individual Seat
Continuous Seat
Figure 12
Dimensions of Passenger Seats
(See Paragraph 5.7.8.2.)
G (cm)
min
F (cm) min continuous seat Individual seats
20 22.5 25

Figure 14
Seat-cushion Depth
(See Paragraph 5.7.8.3.)
Figure 15a
Seat Spacing
(See Paragraph 5.7.8.4.)

Figure 17
Service Door Entry
(See Paragraph 5.7.1.4.)

Figure 19
Determination of Unobstructed Access to Door
(See Paragraph 5.7.1.10.1.)
Figure 20
Determination of Unobstructed Access to Door
(See Paragraph 5.7.1.10.2.)

1. GENERAL
ANNEX 4
GUIDELINES FOR MEASURING THE CLOSING FORCES OF
POWER-OPERATED DOORS
(See Paragraph 5.6.5.6.2.)
The closing of power-operated door is a dynamic process. When a moving door hits an
obstacle, the result is a dynamic reaction force, the history of which (in time) depends upon
several factors (e.g. mass of the door, acceleration, dimensions).
2. DEFINITIONS
2.1. Closing force F (t) is a time function, measured at the closing edges of the door (see
Paragraph 3.2. below).
2.2. Peak force F means the maximum value of the closing force.
2.3. Effective force F is the average value of the closing force related to the pulse duration:
F
1
= ⋅
∫F (t) dt
T
2.4. Pulse duration T is the time between t and t :
T = t
− t
where t = threshold of sensitivity, where the closing force exceeds 50 N
t = fade-away threshold, where the closing force becomes less than 50 N.
2.5. The relations between the above parameters is shown in Figure 1 below (as an example):
Figure 1

Figure 2
Small Capacity Public Service Vehicle Construction.