In public transportation, low floor is a term describing vehicles such as busses, trolleybusses and trams whose passenger compartment has a floor which is considerably lower than that of traditional cars. A recent development in the transport industry, vehicles of this type have a stepless entry and usually have an area without seating next to at least one of the doors where wheelchairs and perambulators can be parked.

The low floor may extend over the complete or just part of the length of the car. If extended over the full length, there is no place for bogies or even axles connecting corresponding left and right wheels (they would be at a higher level than the floor); this is solved with single-wheel drives: motors integrated into the wheels, and (in case of trams) short carbody sections as the axleless design, constrains bogie movement.[1]

In addition, in buses and trolleybusses a hydraulic "kneeling device" can be used when the car is not in motion, tilting it to one side and thus lowering it even further towards the surface level of the road. This technology enables less mobile passengers to board and leave the vehicle without help from others.

Ultra low floor trams and buses are currently being further developed and are already in use in various parts of the world, generally in urban areas.

Typical floor heights

To put things into perspective, here are some typical floor height for public transport vehicles, old and new:

• Tram Low floor - 300-350mm (except for the Ultra Low Floor model, which has only 180mm)
• Tram High floor - more than 600mm
• Train - 800mm to 1200mm

Low floor tram models

• Citadis
• Cityrunner
• Combino
• Flexity Outlook
• Flexity Swift
• Ultra Low Floor
• Sirio

Low floor buses

• Alexander Dennis Enviro 500
• Citaro
• Nova Bus

Low floor trolleybusses

• Civis