Accessibility

Key design parameters for accessibility such as kerb arrangements, access ramps, tactile ground surface indicators, and pedestrian movement.

Summary of accessibility components by bus stop classification

The table below summarises signs and markings corresponding to each type of bus stop classification and whether the component is essential, recommended or optional.

Where items marked essential are not legislative requirements, departures should be approved by the relevant road controlling authority and public transport authority. 

Table: Summary of key design parameters for accessibility

Download key design parameters for accessibility table [PDF, 219 KB]

Kerb arrangements

The kerb forms a critical interface between the bus and the passenger. For a bus to dock correctly and deploy its ramp safely, kerbs should be provided as an expected minimum at all bus stops. This facilitates basic accessibility.

Kerbs at bus stops should:

• Provide a clear and safe delineation between the road surface for vehicle movement and the footpath or waiting areas for passengers and pedestrians.
• Reduce the step height between the bus floor and the bus stop to help passengers board and alight more easily and quickly. facilitating quicker, safer and more comfortable boarding and alighting times.
• Reduce the gradient of a deployed ramp for wheelchair users, people traveling with assistance animals such as guide dogs, older people, people with prams and young children, and people with luggage.

Considerations for kerb arrangements (discussed next) are:

• Kerb height
• Step height and horizontal gap
• Crossfalls
• Accessible kerbs

Kerb height

Kerbs need to be high enough to minimise the step or ramp up to the bus, while taking into account the variable ground clearance of buses.

• Depending on the local road environment, bus stops should have a kerb height of 150–160mm.
• A 150mm ‘standard’ kerb height is desirable along the length of the passenger hardstand area to minimise the step up to the bus from the kerb.
• A minimum height of 120–140mm should be provided if the desirable kerb height cannot be achieved (for example, due to severe crossfall issues).
• From an accessibility perspective, it is important to recognise that even when deployed on a minimum 120mm high kerb, the gradient of the bus ramp may vary (see the figure below). The major determinants include:
  • ramp type
  • ramp length
  • roadway and footway crossfalls
  • the distance of the bus from the kerb
  • the ‘kneeling’ height of the bus floor
  • whether the bus is heavily laden.

See also:
PTDG: Accessible kerbs

Although a large proportion of New Zealand urban buses can ‘kneel’, the reduction in step height achieved by kneeling is not necessarily uniform along the side of the bus. If the kneeling system operates on the front axle alone, the front door will be lower than the centre door. Alternative kneeling configurations include tilting of the near-side of the bus or lowering of the entire vehicle. 

Horizontal gaps, ramp gradient and step height. (Source: Flow Transportation Specialists) 

The use of higher kerbs and the transition between them need careful consideration because:

• bus overhang may ground and damage the bus and the kerb face
• bus drivers fear this possibility, so may not dock the vehicle flush with the kerb face, negating the benefit of these kerbs.

These risks can be mitigated by providing the correct bus stop layout with the correct lead-in and lead-out and appropriate driver training. However, existing bus stops with higher kerbs may not allow buses to approach correctly (for example, when road camber is severe).

Before increasing kerb heights, review the layout of each bus stop to ensure no conflict will occur. Factors to consider include the following.

• Ground clearance of buses – Although bus stop layouts are designed to avoid the need for buses to overhang the kerb on arrival or departure, it may occur at sites with, for example, constrained layouts or inconsiderate parking. In this case, the kerb should be no higher than the minimum ground clearance of the bus.
• Proximity of driveways – If the bus stop is close to a driveway, the ability to increase the kerb height may be limited. Bus stops may have to be relocated slightly to facilitate raised kerbs and not affect the driveway. 

Kerb and footpath damage from bus scraping associated with inadequate ground clearance (Credit: Lorelei Schmitt)

Step height and horizontal gap

The bus stop layout should allow the bus to stop parallel to and as close to the kerb as possible. This makes it easy and safe for passengers to get on and off the bus.

The critical dimensions to consider are the:

• vertical gap (step height) from the kerb to the bus floor
• horizontal gap from the kerb edge to the side of the bus.

The design should aim to minimise these two distances.

Crossfalls

Where kerb heights are changed, consider carriageway and footpath crossfalls carefully. Footpath crossfalls should have a gradient of no more than 2% within the clear stand area, as a steep backfill from the kerb is undesirable for customer safety and comfort.

Accessible kerbs

The ideal kerb arrangement should provide close vertical and horizontal alignment between the bus floor and adjacent footway.

Consider using accessible kerbs, such as Kassel kerbs (see the figure below). These kerbs have a profile to help guide the bus along the kerb edge and into a position that reduces the horizontal gap between bus and footpath without damaging the wheel and tyre.

Accessible kerbs are available in different heights with 160mm and 180mm being most common. The preferred height for a Kassel kerb is 160mm, although site-specific circumstances may mean a different height is appropriate.

Accessible kerbs of more than 160mm should be provided at bus stops only where buses always have clear, flat, unimpeded access on the approach and departure from the boarding point and no likelihood of any obstruction that would prevent the bus arriving parallel to the kerb without hitting it.

Consider accessible kerbs for:

• new or upgraded bus stops or bus interchanges
• any new busway, dedicated bus road project or large-scale streetscape project
• bus stops on frequent bus service routes or in town and city centres
• kerbs and channels being replaced as part of a renewals programme
• bus stops where the existing kerb is being broken out as part of road works.

Kassel kerb profiles. (Source: Adapted from Flow Transportation Specialists)

Access ramps

Consistency of user experience is very important.

Where kerb and bus door heights can be brought to within about 40mm and the bus docked close and parallel to the kerb, it should be possible for most people, including those using wheelchairs, to get on and off without using the integrated ramp (see figure below).

Small gaps between the kerb and bus floor make it easy for passengers to get on or off. (Source: Auckland Transport)

Where a kerb and bus door height of about 40mm cannot be achieved, it should still be possible to deploy the ramp from the front door with the bus docked close and parallel alongside the kerb (see the figure below). The key to good design is ensure bus drivers are not obliged to position the bus differently to deploy the ramp, as non-ramp users must also be able to get on and off with the bus in the same position.

The maximum gradient allowed for the step ramps formed between two horizontal surfaces is 12.5% or 1:8 (see NZS 4121:2001 and Requirement for Urban Buses).

More standards for kerb ramps are in section 4 of NZS 4121:2001.

NZS 4121:2001(external link)

Requirement for Urban Buses

Accessible ramp. Note the narrow width of the boarding island next to the cycleway creates a conflict with the cycleway that the driver is standing on. (Credit: Brenda O’Donoghue)

The requirements for new urban buses are that wheelchairs and prams load at the front.

Wheelchair ramps of about 800mm wide and about 800mm long are fitted to all new and a large proportion of older urban buses.

Tactile ground surface indicators

Tactile ground surface indicators at a bus stop in Dunedin (Credit: Mark Edwards)

Tactile ground surface indicators provide visual and sensory information about the road environment. They assist people with vision impairments to access the bus from the adjoining footpath by warning and directing them.

• Tactile indicators warn people about the kerb and potential hazard beyond it. Warning indicators of 600mm x 600mm (a square layout) should be installed approximately 400mm-450mm back from the front of the kerb edge, adjacent to a bus stop, preferably close to the location of the entry door.  This will location will support sufficient distance between bus swing hazard and someone waiting to board the bus, but not so much space that a pedestrian could inadvertently bypass the warning indicator.  Note this square layout of warning tactile indicators should only be used at bus stops, leading to the door of the bus.  At crossing points, the width of the warning tactile indicators should be the full width of the path/ pram crossing, being a minimum width of 900mm, as per RTS14 guidelines.
• Tactile indicators direct people from the footpath to the kerb where the bus front door will be and from the bus back to the footpath. Where warning indicators are not in the direct line of a continuous accessible path of travel, directional indicators 600mm wide should be installed, when necessary to provide guidance, to form a continuous path leading to the warning indicators. Overuse of directional indicators can be uncomfortable for some users.

RTS14 - Guidelines for facilities for blind and vision impaired pedestrians [PDF, 1.6 MB]

A recommended layout for tactile ground surface indicators at bus stops is shown in the figure below.

Recommended layout for tactile ground surface indicators at bus stops. (Source: Auckland Transport) View larger image [JPG, 37 KB]

Pedestrian movement

Bus stop design should allow for both the safe and easy movement of pedestrians along the footpath and for an adequate waiting area for bus passengers.

Bus stops should be located where footpaths are wide enough, so waiting bus passengers do not obstruct passing pedestrians. A continuous accessible (safe, obvious, step-free) pedestrian through route of at least 1.8m, should be provided for the full length of the bus stop.

A minimum 9–10m should be paved at the bus stop box, forming a 1.8m x 9–10m (16.2–18m2) paved hardstand area free of fixed obstacles. This length of ‘landing pad’ means both bus doors have access to the hardstand. In constrained locations, a minimum footpath width of 1.5m may be acceptable.

If an existing footpath is too narrow, consider locating the bus stop where the footpath can be widened, without compromising other location criteria. This is especially important for bus stops alongside retail activity or other busy places.