Bus Classes Under UN R107: Class I, II, III, A and B

A bus class under UN Regulation No. 107 is a type-approval status, not a marketing label. It fixes standing capacity, door count, gangway width and the mass the approval assumes per passenger.

Where the classes come from

Regulation (EU) 2018/858, Article 4, splits passenger vehicles by seat count and mass: M2 covers vehicles with more than eight seating positions besides the driver and a maximum mass not exceeding 5 tonnes, M3 the same seat count above 5 tonnes. Neither says anything about how the vehicle is used.

UN Regulation No. 107 does. It applies to every single-deck, double-deck, rigid or articulated M2 or M3 vehicle (paragraph 1.1), excluding secure prisoner transport, ambulances, off-road vehicles and vehicles specially designed for carrying school children (paragraph 1.2). It then divides them on capacity: above 22 passengers in addition to the driver, Classes I, II and III (paragraph 2.1.1); at 22 or fewer, Classes A and B (paragraph 2.1.2). Paragraph 2.1.1.4 lets a vehicle belong to more than one class and be approved for each. Figures below come from the consolidated text at Official Journal L 52 of 23 February 2018, current to Supplement 1 and Corrigendum 1 to the 07 series of amendments.

Class I: the city bus

Paragraph 2.1.1.1 defines Class I as vehicles constructed with areas for standing passengers, to allow frequent passenger movement. Capacity then becomes arithmetic: Annex 11, paragraph 3.2.3.2.1 sets the conventional space for one standing passenger at 0.125 m² in Classes I and A, and passenger mass at 68 kg.

That arithmetic runs in two stages. Annex 3, paragraph 7.2.2.1 derives the total passenger area S0 by deducting from the floor the driver’s compartment, door steps, baggage space, staircases and — paragraph 7.2.2.1.3 — any part where vertical clearance falls below 1,350 mm, or 1,200 mm in Classes A and B. Paragraph 7.2.2.2 then derives the standing area S1 from S0, deducting excessive slopes, anything out of reach when every seat is occupied, any area lower than the gangway height of paragraph 7.7.5.1, the floor forward of the driver’s seat, the 300 mm in front of every non-folding seat — 225 mm for a sideways-facing seat, with no wheel-arch condition (paragraph 7.2.2.2.5) — and any surface that will not take a 400 × 300 mm rectangle.

Door counts scale hard: paragraph 7.6.1.1 requires one service door for 9 to 45 passengers, two for 46 to 70, three for 71 to 100 (two if double-deck) and four above 100. Each rigid section of an articulated vehicle needs one, the front section of a Class I articulated vehicle two.

Circulation space is the most generous of the five classes: the Class I gangway gauge in Annex 4, Figure 6 is 1,900 mm tall overall, with a 450 mm lower cylinder and a 550 mm upper cylinder. Slope is capped at 8 per cent longitudinally and 5 per cent transversely, the first step from the ground at 340 mm, internal steps at 250 mm. Seat spacing is the smallest the Regulation permits, 650 mm between squabs — a figure Class I shares with Classes A and B (paragraph 7.7.8.4.1).

Class I also carries the Regulation’s only mandatory accessibility duty. Paragraph 5.2 requires accessibility for people with reduced mobility per Annex 8: a wheelchair space at least 750 mm wide and 1,300 mm long; a ramp at least 800 mm wide whose slope onto a 150 mm kerb should not exceed 12 per cent (the Regulation’s word is “should”, not “shall”); a first step of no more than 250 mm at one service door; four priority seats (paragraph 7.7.8.5.3). A low-floor vehicle (paragraph 2.1.4) is a Class I, II or A vehicle with at least 35 per cent of the standing area step-free and access to at least one service door.

Class II: the intercity bus

Paragraph 2.1.1.2 defines Class II as constructed principally for the carriage of seated passengers, but designed to allow standing passengers in the gangway and/or in an area not exceeding the space provided for two double seats. That last clause is the commercial difference: surge capacity without city-bus architecture.

The mass assumptions move with it: 71 kg per passenger including 3 kg of hand baggage, 0.15 m² of conventional standing space. Doors relax to one up to 70 passengers, two from 71 to 100, three above 100. The gangway gauge keeps the 1,900 mm height and 550 mm upper cylinder but narrows the lower cylinder to 350 mm. Seat spacing rises to 680 mm, the first step from the ground may reach 380 mm, and two priority seats are required.

Declared baggage mass is not a Class II feature: Annex 11, paragraph 3.2.3.2.1 sets B at no less than 100 kg per cubic metre of baggage compartment volume and roof baggage BX at no less than 75 kg/m² for any vehicle so equipped, whatever its class. Its one class-linked rule runs the other way: double-deck vehicles may not carry roof baggage, so BX is zero. Class II shares with Classes III and B escape hatches beyond the emergency doors and windows — one up to 30 passengers, two above — and inclusion in UN Regulation No. 66 on superstructure strength, which covers single-deck rigid or articulated M2 and M3 vehicles of those three classes above 16 passengers. Class I sits outside it.

Class III: the coach

Paragraph 2.1.1.3 is a single line: vehicles constructed exclusively for the carriage of seated passengers. Annex 11 turns that into arithmetic, because for Classes III and B the standing area S1 is zero: no Ssp value, no standing capacity to declare.

The consequences run opposite to Class I. One service door satisfies the door table at any capacity — though paragraph 7.6.1.1 opens by requiring two doors in any vehicle, two service doors or one service door and one emergency door, and paragraph 7.6.1.4 scales total exits with occupancy, from two at 1 to 8 passengers to eleven above 130. The gangway gauge drops to a 450 mm upper and 300 mm lower cylinder, and paragraph 7.7.5.3 lets laterally movable seats narrow the aisle to 220 mm provided a control at each seat returns it to 300 mm. Longitudinal slope may reach 12.5 per cent; passenger mass is 71 kg with hand baggage; minimum seat spacing 680 mm.

Accessibility is not mandated. Paragraph 5.3 leaves Contracting Parties free to choose how to improve access outside Class I, but any feature fitted must comply with Annex 8 — minimum two priority seats.

Classes A and B: 22 passengers or fewer

Below 23 passengers the question is binary: Class A vehicles are designed to carry standing passengers and shall have provision for them, Class B vehicles are not and have none.

Class A inherits Class I’s numbers: 68 kg per passenger, 0.125 m² per standing passenger, a 1,900 mm gangway gauge, the 8 per cent slope limit, one priority seat. Class B’s gangway gauge is 1,500 mm tall with a 300 mm lower cylinder, and Annex 7 sets its service door entry height at 1,500 mm against 1,650 mm for Class A. Class B above 16 passengers falls under R66; Class A does not.

What the road allows

Class choice is bounded by Directive 96/53/EC: 13.50 m for a two-axle bus, 15.00 m with more axles, 18.75 m articulated; 2.55 m wide, 4.00 m high. Two-axle buses are limited to 19.5 tonnes and three-axle articulated buses to 28 tonnes, but weights bind more narrowly than dimensions. Article 3(1) bars a Member State from refusing another Member State’s vehicle on weight or dimension grounds in international traffic, whereas Article 4(1) binds national traffic to Annex I’s dimension points only, not the weights of point 2. That 28 tonnes rises by the weight the technology adds: up to 1 tonne for an alternatively fuelled vehicle, 2 tonnes for a zero-emission one, with no equivalent allowance for two-axle buses. R107 adds that the driving axles must carry at least 25 per cent of maximum mass M; the front axle at least 20 per cent on rigid Class I and A vehicles and 25 per cent on rigid Class II, III and B, falling back to 20 on three-axle Class II and III vehicles with two steered axles (Annex 11, paragraph 3.2.3.3).

Choosing a class

Frequent stops, short rides, standees and kerbside wheelchair boarding point to Class I, and to the low-floor variant where routes have no raised platforms. Peak-hour overload on commuter work points to Class II, the only class that sells both seats and a bounded number of standing places; general-service vehicles on school contracts sit here too, as distinct from the purpose-built school vehicles paragraph 1.2.4 puts outside the Regulation. Long-distance charter, tourism and airport transfer point to Class III, whose approval carries no standing capacity. Below 23 passengers, the A-versus-B choice turns on whether passengers need to stand. Annex 11, paragraph 3.3.1 requires every vehicle to be marked clearly inside, visible to the driver in his seating position, with its maximum seating places, standing places and wheelchairs.

Procurement narrows it further. Directive (EU) 2019/1161 rewrote Directive 2009/33/EC, whose Article 3(2)(b) now excludes category M3 vehicles other than Class I and Class A; Table 4 of the Annex, whose bus column covers M3, therefore reaches Class I and Class A buses only. Table 4 bands the minimum clean-vehicle share in public bus contracts by Member State: the top band — 45 per cent to the end of 2025, 65 per cent from 2026 to 2030 — applies to thirteen rows, twelve Member States plus a United Kingdom row the consolidated text still carries, and falls as far as 24 and 33 per cent for Romania. Half of each target must be met by zero-emission buses, cut to a quarter in the first period where more than 80 per cent of the buses procured in that Member State are double-deckers.

ACEA recorded 38,238 new EU bus registrations in 2025, up 7.5 per cent, electrically-chargeable vehicles at 23.8 per cent and diesel at 62.1 per cent. Weigh that against fleet age: EU buses average 12.5 years, and only seven Member States run a fleet younger than ten years.