A low-floor bus is a bus or trolleybus that has no steps between the ground and the floor of the bus at one or more entrances, and low floor for part or all of the passenger cabin. A bus with a partial low floor may also be referred to as a low-entry bus or seldom a flat-floor bus in some locations.
Low floor refers to a bus deck that is accessible from the sidewalk with only a single step with a small height difference, caused solely by the difference between the bus deck and sidewalk. This is distinct from high-floor, a bus deck design that requires climbing one or more steps (now known as step entrance) to access the interior floor that is placed at a higher height. Being low-floor improves the accessibility of the bus for the public, particularly the elderly and people with disabilities, including those using wheelchairs and walkers. Almost all are rear-engine, rear-wheel-drive layout.
Configuration
Low-floor and low-entry buses Low-floor buses are generally divided into two major types: fully low-floor buses with a low floor throughout the length of the bus (more popular in Europe), and low-entry buses with step-free access to only a part of the bus, most commonly between the front door and the middle door (more popular in North America). In North America, both types are commonly called low-floor, as the majority of the vehicle has a low floor, without steps at the doors.
The main reason for choosing a low-entry configuration is to allow better placement for the powertrain and other technical equipment in the raised floor section, in addition to allowing a more comfortable ride on rough roads. Some manufacturers use the initials LF or L in their model designations for fully low-floor models (or in the case of German manufacturers, NF or N, based on the German word Niederflur, which means low floor), and in North America buses that are partially low-floor are often also designated LF. In some countries, LE, short for Low Entry, is used by some manufacturers in their model designations for low-entry buses.
Suspension and powertrain
Most bus manufacturers achieve a low floor height by making rear-engined rear-wheel drive buses with independent front suspension, so that no axle is needed to pass under the floor of the front part of passenger compartment, or a lowered front axle. Some full low-floor buses also have a lowered rear axle, while the rear axle is not an issue on a low-entry bus.
Many low-floor buses, including the Irisbus Citelis (also in Skoda 24Tr trolleybus version), have the engine in a vertical cabinet at the rear of the bus. Van Hool have a series of "side-engine mid-drive" buses that puts the engine off to one side of the cabin longitudinally between the first and the second axle, to maximize usable cabin space. The same concept was also utilized by Volvo on their B9S articulated chassis.
For smaller buses, such as midibuses, the low-floor capability is achieved by placing the front wheels ahead of the entrance. One of the last types of buses to gain low-floor accessibility as standard was the minibus, where a similar front-wheel arrangement allows around 12 seats and a wheelchair space to be accommodated in very small low-floor minibuses, such as the Optare Alero and Hino Poncho. Accessibility was previously achieved in paratransit type applications, which use small vehicles with the fitment of special lifts. The inception of small low-floor buses has allowed the development of several accessible demand-responsive transport schemes using standard 'off-the-shelf' buses.
A disadvantage of the low floor is accommodating the bus's own wheels. With the low floor, the wheels protrude into the passenger cabin, and need to be contained in wheel pockets of waist height, and this occupies space which would otherwise be used for seating. To allow space for technical equipment, many low-floor buses have the seats mounted on podiums, making a small step up from the floor, while others are able to mount the seats directly to the floor, avoiding the step. Seating layout for a low-floor bus therefore requires careful design. Low floor configuration is also known to have poor side to side dead load distribution within the chassis due to the asymmetrical off-centre placement of driveline components - mainly engine and transmission. As a result, many of such buses require electronically controlled air suspension to compensate the lopsided configuration.
Other features
Low-floor buses usually include an area without seating (or seating that folds up) next to at least one of the doors, where wheelchairs, walkers, strollers/prams, and where allowed even bicycles, can be parked. This is sometimes not the only purpose of this area, though, as many operators employ larger standee areas for high occupancy at peak times. Despite the space existing, operators may also insist that only one or two wheelchairs or pushchairs can be accommodated unfolded, due to space/safety concerns.
Low floors can be complemented by a hydraulic or pneumatic 'kneeling device', which can be used when the bus is not in motion, tilting it or lowering it at the front axle even further, often down to normal curb height. Depending on how close to the curb the bus is parked and wheelchair design, this can allow wheelchair users to board unaided. Though such technology has been available and in use on high-floor buses since the 1970s, it is of significant utility on low-floor vehicles only where it enables less-mobile passengers to board and leave the vehicle without help from others. Many vehicles are also equipped with wheel-chair lifts, or ramps which, when combined with a low floor, can provide a nearly level entry.
An implementation of the low floor design exists in Australia where custom coaches make a "hybrid" variant of its CB60 bodywork. These buses combine a smaller low floor area with a small underfloor bin for some luggage. Whilst these buses do not provide a full amount of luggage space, they can be used to house more luggage than what can be held inside the bus itself. Another drawback is the arrangement means the section of the bus that is at curb height is very short—consisting of enough space to house the wheelchair area and then rising up, to accommodate the luggage bin. These buses also lack the ability to have a center door.
Alternatives Many bus rapid transit systems employ a level boarding by using high-floor buses stopping at "station" style bus stops. Specially raised sections of curb may also be used to achieve accessibility with lesser low floor models, although this is more expensive for the operator, and only attractive for regular busy scheduled routes. For infrequent routes or routes with hail and ride sections, or demand responsive transport, raised curbs would only be feasible in terminuses.
Asia
India
Bangalore Metropolitan Transport Corporation Bangalore is one of the first cities in India that introduced Low Floor buses. The Bangalore Metropolitan Transport Corporation, BMTC operates many services using the premium Volvo 8400LE Low-floor buses. These buses are air-conditioned, and offer features such as automatic transmission, kneeling and wheel-chair ramp, typical of modern city buses. They are also fitted with LED display boards as well as ITS to announce the halts. The corporation also had tried Mercedes-Benz Low-Floor buses as well as Ashok Leyland ULE coaches, but chose to stick to the Volvo offering.
In order to keep the bus ticket prices low, the BMTC operates the majority of their services using Non-Airconditioned Semi-Low Floor (SLF) buses that have a floor height of 650mm as against the 400mm floor height of the true Low-Floor buses. These buses are from Ashok Leyland and Tata Motors, with future procurements planned to be from Eicher (VECV). These cheaper alternative to low-floor buses do not have kneeling or wheel-chair accessible ramps, but they have air suspension and use the same or better seats as those found in the Volvo buses. They also feature manual transmission as against automatic transmission
New Delhi
With the introduction of Bus Rapid Transit (BRT) and the development of dedicated corridors for the service, bus service is set to improve. The Delhi Transport Corporation (DTC) has started introducing air-conditioned buses and brand new low-floor buses (with floor height of and even higher on one third area as against available internationally) on city streets to replace the conventional buses. A revamp plan is underway to improve bus-shelters in the city and to integrate GPS systems in DTC buses and bus stops so as to provide reliable information about bus arrivals. The Delhi Government decided to expedite this process and procured 6,600 low floor buses for the DTC before commonwealth games in 2010.
Kolkata
Kolkata has an extensive network of government run buses. Recently air-conditioned buses have been introduced by the WBSTC. These buses connects places like the Kolkata Airport, Barasat (Capital Town of North Suburb), New Town, Salt Lake, Howrah, Santragachi (a station on the Howrah-Kharagpur railway line), Kudghat and Tollygunge. The road network in Kolkata is vast. Under Jawaharlal Nehru National Urban Renewal Mission, air conditioned buses have been included as a part of travel comfort to commuters. Air-conditioned buses are operated by West Bengal Surface Transport Corporation (WBSTC) directly & through outsourcing. These buses are served by Tata Marcopolo Buses and Volvo Low Floor Buses. The V Series and VS series bus routes are served by the AC volvo bus and MW series are served by the Tata Marcopolo buses operated by WBSTC. AC Marcopolo buses serve the MH series route operated by WBHIDCO and the MB series route operated by BHBL. Calcutta State Transport Corporation (CSTC) also run AC Volvo Bus & Ashok Leylan JanBus.
Jaipur (Jaipur)
Non-AC : Several Non-AC buses are available across the city. There are 10 routes.7 are radial and 10 are circular AC: There are six AC routes buses namely AC-1, AC-2, AC-3, AC-5, AC-6 and AC-7. JCTSL operates buses from Ashok Leyland and Tata
Japan
In Japan, a low-floor bus is called "non-step bus (ノンステップバス)". Mitsubishi Fuso Truck and Bus Corporation used to calling a low-floor bus "no-step bus (ノーステップバス)".Japanese "ノーステップバス" At Enshu Railway Company in Hamamatsu Area, a low-floor bus is called "omnibus (オムニバス)", "cho-teisho bus (超低床バス; very low-floor bus)" and "cho-teisho omnibus (超低床オムニバス; very low-floor omnibus)". Japanese government calls a low-floor bus "cho-teisho non-step bus (超低床ノンステップバス; very low-floor non-step bus)".
Philippines
The Land Transportation Franchising and Regulatory Board (LTFRB) mandates the use of low-floor or low-entry buses on city bus routes in the Philippines since 2016.
Low-floor buses are used on city bus networks in Metro Manila, Metro Cebu and Davao City, and on some provincial routes, and most Point-to-Point Bus services, although older coaches are still largely used for such services.
Buses used on the EDSA Busway are usually equipped with 1-2 doors on the left side for boarding at the median stations, although not all units currently have them installed.
Low-floor buses often use upholstered coach-style seating in a 2-3, or 2-2 configuration, although plastic seats may be found in some buses.
Singapore
Low-entry wheelchair-accessible buses were first introduced in Singapore in 2006 with 150 Volvo B9TL ComfortDelGro Engineering buses procured by SBS Transit. These units were registered SBS7300P - SBS7499A. All Volvo B9TL ComfortDelGro Engineering buses were fully retired by September 2023.
In 2007, SBS Transit procured 1,101 units of low-entry Scania K230UB buses bodied by Gemilang Coachworks of Senai, Malaysia. Afterwards, all city buses procured by SBS Transit, SMRT Buses and the Land Transport Authority are low-floor interior as respectively.
As of July 2025, all public buses in Singapore are low-floor layout.
Europe
Germany