Double-decker buses: height, length, seats and upper-deck rules

A double-decker bus carries passengers on two levels, one above the other. UN Regulation No. 107 defines a double-deck vehicle as one where the spaces for passengers “are arranged, at least in one part, in two superimposed levels and spaces for standing passengers are not provided in the upper deck”. Makers’ documents give heights from 4,000 mm to 4,395 mm, lengths from 10.5 m for a city bus to 15.0 m for a three-axle coach, and up to 100 passengers on a city bus. The height limit is 4.00 m in Annex I of Directive 96/53/EC, which an EU Member State may relax for national passenger transport, and 4.57 m for a bus in England, Wales and Scotland.

Status as at 5 November 2026. The makers’ pages and data sheets and the British regulations were read on 4 November 2026; the dated data sheets run to November 2026 (Alexander Dennis), and the Volvo data sheet carries no date. UN Regulation No. 107 is the text published in the Official Journal on 29 January 2026, incorporating the 11 series of amendments. Directive 96/53/EC is the consolidated text of 14 August 2019.

What counts as a double-decker

Article 2 of Directive 96/53/EC says a bus “may have one or two decks”; the word appears nowhere else in the Directive, and Annex I sets one set of limits for both. UN Regulation No. 107 applies to “every single-deck, double-deck, rigid or articulated vehicle of category M2 or M3” (paragraph 1.1) and also defines a double-decker articulated vehicle, whose sections intercommunicate “on at least one deck” (paragraph 2.1.3.1). Its gangway table lists double-deck vehicles in Classes I, II and III; the classes themselves are set out in bus classes under R107. The bodywork codes in vehicle categories M, N and O separate double-deck, double-deck articulated, low-floor double-deck and open-top double-deck vehicles.

Not every bus rule reaches the second deck. Paragraph 1.1 of UN Regulation No. 66 on superstructure strength, in the 02-series text, names single-deck vehicles only, as the R66 page sets out.

How tall a double-decker may be

Annex I of Directive 96/53/EC gives one figure, “Maximum height (any vehicle)”, at 4.00 m (point 1.3). The Neoplan Skyliner and the Setra S 531 DT are 4,000 mm high, as bus and coach dimensions records with the rest of the EU rules. Point 1.3 is among the points for which Article 4(2)(b) lets a Member State authorise “vehicles for national passenger transport” that do not conform.

Great Britain has its own figure. Regulation 9(1) of the Road Vehicles (Construction and Use) Regulations 1986 reads: “The overall height of a bus shall not exceed 4.57 m.” It extends to England, Wales and Scotland and has been in force since 11 August 1986. The Alexander Dennis, BYD and Wrightbus heights in the next section, from 4.2 m to 4,395 mm, lie between the two limits.

Countries without a row are not covered.

City double-deckers: size and capacity

Seats and total capacity. Wrightbus’s maximums do not add up to one another. On the 10.6 m Ultroliner, 75 seats and 28 standing would make 103 against a maximum capacity of 100; on the Electroliner, 73 and 14 make 87 against 84; on the Hydroliner, 69 and 24 make 93 against 90. The Ultroliner page says: “Depending on specification choice, a maximum capacity of up to 100 can be achieved.” Alexander Dennis pairs seats with a total for each specification: the difference between the two is 16 on the UK Enviro400EV and 25 on the London version.

Upper and lower deck. The upper deck has more seats than the lower in every layout in the Alexander Dennis documents listed here. The sample layouts give 46 upper seats against 24 fixed and 5 tip-up seats on the 10.9 m Enviro400, 51 against 33 and 1 on the 11.5 m Enviro400 stock bus, and 47 against 23 and 2 on the 11.1 m Enviro400EV.

Headroom. Alexander Dennis gives 2.01 m on the lower deck and 1.74 m or 1.84 m on the upper. Its single-specification leaflets pair height and headroom: the Enviro400 stock bus is 4.2 m high with 1.74 m on the upper deck, and the Enviro400EV for London 4.3 m high with 1.84 m.

Weight. Alexander Dennis gives unladen weights of approximately 10,800 to 11,500 kg for the Enviro400, approximately 13,650 kg for the UK Enviro400EV and approximately 13,500 kg for the London version. Point 2.3.1 of Annex I to Directive 96/53/EC gives 19.5 tonnes for a two-axle bus, the gross figure of the battery-electric and hydrogen models above; the traffic those weights govern is covered in bus classes under R107. The Ultroliner data sheet lists both 18,600 kg and 19,500 kg under gross vehicle weight, and the model page 18,600 kg.

Double-deck coaches

Neoplan’s brochure says: “In 1967 NEOPLAN created the double-decker touring class”. The coaches in the table all run on three axles: front, drive and a steered trailing or auxiliary axle.

Point 1.1 of Annex I gives 15.00 m for a bus with more than two axles, which is the Volvo’s length. Its width and height are above the 2.55 m and 4.00 m of points 1.2 and 1.3. The Volvo data sheet is issued by Volvo Buses México; the specification page names no market. For weight, point 2.3.2 gives three-axle motor vehicles 25 tonnes, or 26 tonnes where the driving axle has twin tyres and air suspension or recognised equivalent suspension, or where each driving axle has twin tyres and no axle exceeds 9.5 tonnes.

The same kinds of figure on a single-deck coach sheet are read against these texts in how to read a coach specification sheet.

What UN R107 requires of a double-decker

The table lists what the Regulation sets for a double-deck vehicle in particular; paragraphs numbered 7 are in Annex 3. Door and exit counts are in bus doors and emergency exits.

The 28-degree tilt. Paragraph 7.4.1 requires that “the point at which overturning occurs would not be passed if the surface on which the vehicle stands were tilted to both sides in turn to an angle of 28 degrees from the horizontal”. The vehicle is at its mass in running order, with loads placed on each passenger seat, “of the upper deck only in the case of double-deck vehicles” (paragraph 7.4.2.1), and the baggage compartments hold no baggage. A crew member who is not seated counts as 75 kg in the upper-deck gangway. Paragraph 7.4.5 allows a calculation method instead of the physical test.

None of the makers’ documents listed here names R107. Wrightbus’s sheets state “Certified to NSSTA requirements” or, on the Ultroliner, “Certified to UK NSSTA”, without defining the term, and the British approval rules for buses were not verified.

Open-top double-deckers

R107 calls this a vehicle without roof: “In the case of a double-decked vehicle this shall be the upper deck”, and “Space for standing passengers shall not be provided on any deck without roof, independently of the class of vehicle” (paragraph 2.1.9). Exits on that deck meet the requirements that are not incompatible with the absence of the roof (Annex 3, paragraph 7.6.1.16), and at least one lighting device is provided as near as practicable to the top of every staircase to that deck (paragraph 7.8.1.6).

Wrightbus’s StreetDeck Open Top Electroliner data sheet gives 11,302 mm in length, 2,520 mm in width and 4,395 mm in height, a maximum capacity of 96 with up to 74 seated and 28 standing, and 19,500 kg gross. It lists a 340 kWh battery and a range of approximately 150 miles, where the model page says “up to 200 miles”. The sheet heads its dimensions column “10.6” above that 11,302 mm length.

Battery, hydrogen and diesel

All three battery-electric models charge by CCS plug; Alexander Dennis offers optional roof-mounted rails for pantograph charging, and BYD an optional pantograph with up to 500 kW. How these systems work is covered in electric buses explained and opportunity charging, and the Hydroliner alongside other fuel-cell buses in hydrogen fuel cell buses and coaches. The Clean Vehicles Directive (2009/33/EC) had a lower zero-emission requirement for a Member State where double-deckers made up more than 80 % of the buses under contracts awarded in its first reference period, which ended on 31 December 2025; public bus procurement under the Directive sets it out.