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Accessibility in bus transport

Bus technology has undergone rapid change over the past 30 years – so much so that many parties have not managed to keep up. For municipalities, bus operators, public authorities and planners, it is often not clear what changes are needed, and exactly these changes should be implemented, in order to make public bus transport accessible for people with disabilities.

1. An actual topic

We dedicated the first Procap Magazin issue in 2018 to the topic to explain what problems are encountered by those affected.

In order to understand the technical and legal aspects of what is needed and how the challenges should be dealt with, we need to understand the origins of the vehicles used in bus transport.

2. The development of same-level access in public transport

The development of low-floor buses began outside Switzerland from 1970 onwards. Essentially, the low-floor buses had the aim of reducing the number of steps required for boarding to one, compared to the two or three stairs on the rigid-axle high-floor buses that were common at the time. The main motivation for this new design was to cut the time needed for boarding and alighting during passenger operations. The move was based on experiences with same-level design on metro services commonly found in major cities. While with high-floor buses, the focus was placed on reducing the initial climb to that of a normal step (requiring a 12 cm kerb height), low-floor buses needed a different system to allow boarding. This includes height, but also the design needed to allow the vehicle to closely approach the kerb. From 1990 onwards, this led to the trend of various types of “special kerbs”. These are characterized by a guiding system that includes a rounded section for the wheels. The aim is to avoid damage to the tyres and stop them jumping up on to the pavement, while also preventing the chassis from colliding with the road surface. This results in a kerb that is about 30 cm in height, which has also proven to be a good access height for low-floor trams. As the 30 cm height of these multi-purpose bus stops[1] requires a major increase over standard pavement heights of 6-8 cm, attempts were made to improve on the height. An important technology used for this is called kneeling. This allows buses to lower themselves by about 6 cm in the stopping position. It permits the kerb height to be reduced to 22 cm. The pioneering standard for the design of accessible transport facilities from the Swiss Association of Road and Transport Experts, VSS 640 075, “Pedestrian traffic – accessible transport environments”, specifies in its normative appendix appropriate bus kerb heights to be 22 to 30 cm. Procap working paper A516 clearly summarizes the current requirements for same-level access.

3. Swiss Disability Discrimination Act (DDA)

While the trend towards same-level access and bus technology moved ahead in other countries, Switzerland took a wait-and-see approach. The situation suddenly changed when the Swiss Disability Discrimination Act (DDA) came into force in 2004. However, the implications of the change were not appreciated by bus operators, transport planners and approval bodies for a considerable period. The Disability Discrimination Act (DDA) stipulates that people with disabilities must be able to use public transport autonomously.  The legislation requires that bus operators and bus stop owners make adjustments by the end of 2023.

Relevant to the design of bus stops are the two ordinances for the DDA, the Public Transport Adaptation Ordinance[1] (PTAO) and the DETEC Ordinance on the Technical Requirements for Adapting Public Transport to the Needs of Disabled People[2](RATDO). These require as a basic principle the use of low-floor buses and autonomous access for wheelchair users. For both ordinances, there are notes from the Swiss Federal Office of Transport (FOT) which are very helpful for understanding. For construction design, these documents refer to two standards: SIA 500, “Accessible construction”, from the Swiss Society of Engineers and Architects (SIA), and VSS 640 075, “Pedestrian traffic – accessible transport environments”, from the Swiss Association of Road and Transport Experts (VSS). While the Federal Office of Transport can directly manage railway design by means of permits/concessions, implementation for buses is far more difficult. The implementation there is the responsibility of the cantons and their municipalities, with a multitude of relevant building authorities. A complicating factor is the fact that there are far more bus operators than there are train ones.

The Federal Office of Transport reacted to the entry into force of the Disability Discrimination Act in 2004 by commissioning the study “Wheelchair-friendly bus access”.  The 2006 publication confirmed the usefulness of the special kerbs and the need for tractrix curve inspections. The intervention by the Confederation was for a long time seen by the cantons as a breach of their sovereignty. This clash resulted in overly low bus stops being built – something which continues even today in places – and folding ramps being used, even in cases where same-level access would be possible. In the Walenstadt railway station judgment (A-7569/2007) from 2008, however, the Swiss Federal Supreme Court ruled that the independence of people with disabilities should be the highest priority. The court said that this should normally be provided by means of same-level access, with folding ramps being used only in a supplementary role, i.e. when same-level access is structurally impossible or would require a disproportionate level of effort. The question about what would be disproportionate, particularly in terms of weighing up various requirements and interests, was for a long time disputed. Public authorities and planners tended to give preference to other needs by regularly portraying the efforts needed for compliance with the Disability Discrimination Act as being disproportionate. The Lausanne court judgment (AC 2016.0321) from 2018 provided clarification on this point. The court determined that the needs of people with disabilities should be given priority on public transport when there are competing needs.

4. Implementation in practice

This raises the question of how individual actors should proceed. We can recommend taking the following action:

Bus operators
When issuing calls for tender for the procurement of new buses, it is essential to ensure that these vehicles are compatible with the 22 cm high special kerbs. Not all vehicles on the market are equally suitable. The focus should be placed particularly on the door and kneeling systems and, for articulated buses, on the concertina extender.

The kneeling function must be set up correctly and undergo regular maintenance. In doing so, it is technically possible for the boarding height to be set with a ± 3 cm tolerance (a maximum of 5 cm is permissible under RATDO, but this is insurmountable for some wheelchair users and many walking frame users[1]).

Bus drivers must be trained in how to approach the special kerbs. They need to know how to approach the individual stops, so that the maximum gap width is adhered to.

Forecasts of future passenger numbers must be developed, along with a list of measures that will be taken to meet the challenges. Longer buses require longer stops and corresponding structural adjustments. These need to be planned for, both in a technical and an economic sense.

Transport planners

The following rules and standards should be consulted before commencing the planning process:

  • PTAO and RATDO
  • The notes by the FTO on the PTAO and RATDO ordinances
  • The SIA 500 standard (if structures are involved, e.g. bus shelters)
  • The VSS 640 075 standard along with the Procap factsheets on public spaces
  • The bus stop factsheet from “Hindernisfreie Architektur”, a specialist body for accessibility in architecture

To collate or swap data relating to experience with same-level boarding, we recommend consulting the civil engineering departments that are taking a leading role on the issue in Basel, Basel-Landschaft, Lucerne, Zurich and Neuchâtel.

The most common design error made is not building the new stops at the most appropriate point on the road’s edge, or not moving existing stops to a suitable location.

Bus stop owners

  1. All newly built stops should be planned and constructed with same-level boarding as standard.

2a.  Given the deadline for making adjustments of the end of 2023, data on the existing bus stops should be collected. As part of this, the situation at each specific site should be recorded and reviewed. The relevant measures for the best possible same-level access should be prioritized in the following sequence, in accordance with VSS 640 075:

  1. Same-level boarding for the entire length of the stop
  2. Shifting of the stop to a more appropriate location
  3. Same-level boarding in an area for people with disabilities, with the remaining kerb height at 16 cm
  4. If no better solution can be found, use the 16 cm height as the fallback level for the entire stop

Stops that are situated in road sections that are due for redevelopment should be altered at the same time as the remediation work.

2b.  Stops in road sections with no need for renovations should be prioritized for alterations in accordance with the following criteria

  1. Passenger flow
  2. Transfer opportunities
  3. Significance of nearby amenities
  4. New amenities being planned for the area
  5. Kerb at least 12 cm

Stops with a high priority should be worked on first when making alterations. For the remediation works the procedure listed in Section 2a should be followed.

In principle, there are no stops that are not of general significance and which are not covered by the Disability Discrimination Act. Proportionality is relevant only when it comes to the downgrading of the kerb formation under Section 2a, or in the prioritization in accordance with Section 2b during the adjustment period in force until 2023. Various planning tools available on the market that classify stops according to their level of accessibility must be rejected due to their lack of compliance with the Disability Discrimination Act. On this issue, we refer to the Inclusion Handicap position paper from November 2016.

Approval bodies

PTAO and RATDO, along with the relevant commentary from FOT and the SIA 500 and
VSS 640 075 standards must form an integral component of the building permit. Newly submitted stops without same-level boarding throughout the entire length of the stop should be critically evaluated to determine whether shifting or improvements are really not possible. Alternatively, documentation about the tractrix curves should be requested in accordance with Section 2a, paragraphs 3-4, and submitted for evaluation by an experienced professional. The cantonal departments for accessible construction would be happy to assist in this regard.

There are already signs that it will be difficult to reach the targets by the end of 2023, because of the years that were lost at the beginning. For this reason, the correct prioritization in accordance with Section 2b is important. Regardless of this, from 2024 onwards people with disabilities and disability organizations will have the right to bring action, both against incorrectly built stops, and against ones that have not been altered.

5. Summary

Same-level or autonomous boarding has been state of the art technology for a long time, and empirical data is available. Some cantons already have significant experience and have corresponding guidelines in place, such as the Canton of Lucerne (“Bus stop guidelines, a summary technical report” from the Lucerne’s Transport and Infrastructure (“vif”) department, December 2017), the Canton of Zurich (“Guidelines for accessible bus stops, recommendations for design” from the Office of Transport for the Canton of Zurich, 30 April 2018), the Canton of Basel-Landschaft (the T 972 publication, “Project guidelines for bus stops”, 22 July 2016) and the Canton of Neuchâtel (“Mise en conformité LHand des arrets de bus du canton de Neuchâtel”, November 2017). Same-level boarding with special kerbs is thus seen generally – and by the courts as well – as a standard solution. For this reason, we absolutely recommend to all cantons to make appropriate changes to their planning guidelines.

As yet, we have not expressed a view about high-floor buses. They differ significantly from low-floor buses by having more seats and storage space underneath the passenger compartment. On individual routes their use may be justified, such as for long-distance transport or due to geographic circumstances. High-floor buses do need to have their routes approved by the FOT and must be equipped with wheelchair lifting devices. However, the lifting devices are not suitable for other affected individuals, e.g. older people with canes or walking frames, or people with prams or luggage. Stops also need to be widened (see VSS 640 075, annex 15.2). For this reason, in these cases what are known as “low-entry buses” could be an alternative. These are a combination of high and low-floor buses, i.e. the front area functions as a low-floor bus, while the rear is a high-floor section (see for example the low-entry bus from the Hess company).

It is important that the purpose and significance of the measures mandated by the Disability Discrimination Act are understood. According to the DDA, the “disabilities” term also includes individuals who due to their age have movement or sensory limitations that are likely to be ongoing.  Beneficiaries of the DDA are ultimately all public transport users: same-level boarding speeds up passenger flow and also assists travellers with heavy luggage and prams. The significance of same-level boarding goes far beyond meeting the needs of those with disabilities.

Future vehicle trends will bring further improvements. For example, we are already seeing the first vehicles that can optimally adjust kneeling to match the height of the kerb. Research is also under way on parking assistance systems that will allow drivers to approach existing stops more easily and with larger vehicles. For all the reasons mentioned, kerbs for buses of 22 cm in height are a sustainable investment in future public transport technology. Kerbs that are 16 cm in height are seen as being technically outdated.

For questions, we refer you to the cantonal departments for accessible construction, which are happy to provide advice.

Further information on accessible public transport technology can be found at:

6. Sources

[1] The first introduction of this type of multi-purpose kerb in Switzerland is located at the Hardbrücke stop in Zurich.

[2] SR 151.34 “Ordinance on the Adaptation of Public Transport to the Needs of People with Disabilities”

[3] SR.342 “DETEC Ordinance on the Technical Requirements for Adapting Public Transport to the Needs of Disabled People”

[4] The 5 cm tolerance for same-level boarding comes from the PRM-TSI rules for railway services. To ensure there is uniformity in the matter, a maximum gap width of 75 mm and a maximum level differential of 50 mm applies to all types of public transport. This guarantees same-level boarding/alighting that can be handled by users autonomously.


Remo Petri
Head of the Department for Building, Housing and Transport
Procap Switzerland
5 October 2018