Project: Extending Comprehensive Access with Local Initiatives for Bus Systems in Urban Areas (EXCALIBUR)

Reference: CSU 28/4/61

Last update: 04/08/2003 09:37:31


To develop consistent and good quality design for accessible public transport systems.


Modelling and simulation will be conducted to facilitate the explicit inclusion of accessibility in the design and implementation of bus systems. Novel features will be tested and evaluated at four trial bus stops.


Centre for Transport Studies
University College London, Gower Street, London, WC1E 6BT
0207 390 1553

George Lines Ltd
Coln Industrial Estate, Old Bath Road, Slough, Berkshire, SL3 0NJ
01753 685354

London Transport Unit for Disabled Passengers
172 Buckingham Palace Road, London, SW1W 9TN
0207 918 3176

East London Bus & Coach Co Ltd
(Stagecoach East London), 2-4 Clements Road, Ilford, Essex, IG1 1BA

Contract details

Cost to the Department: £32,136.00

Actual start date: 09 February 1998

Actual completion date: 09 May 2000


LINK Inland Surface Transport (IST): Project summaries
Author: DfT
Publication date: 01/09/2002
Source: DfT, Research & Technology Strategy Division
More information:

Summary of results

  1. EXCALIBUR designed and constructed an experimental facility to test various aspects of bus stop design from the perspectives of passengers and bus drivers. These experiments allowed us to determine the design standards necessary for the construction of accessible bus stops, including details of surface, crossfalls, step heights, gradients, kerb profiles stopping points and indication methods, and approach paths. It also enabled us to examine a number of drivers and driver-trainers with a view to establishing the consistency with which performance at the bus stops could be obtained. Three kerb types were examined (Kassel, Charcon and Marshalls) and tested for consistency, ease of use, effective reduction of horizontal and vertical gaps and problems in operation. Platform surfaces were tried out, including asphalt, small and large pavers, lozenge tactile surfaces, brick and bar-face paving. In addition crossfalls were constructed on the platform ranging from 1% to 4%. Two mid-platform longitudinal steps of different heights were incorporated to permit testing of trip hazards. The experiments allowed us to test designs for passengers, drivers and buses.
    Passengers with various mobility difficulties were involved with the project, including people with visual impairments, wheelchair-users (powered, pushed and self-propelled) stick and walking frame users. Wheelchair users included people from the very fit to people with low levels of self-powered mobility.
    The surface crossfalls were not a problem - even at 4% - except for the stick user with two sticks who found the steeper crossfalls difficult. Others could barely detect the difference.
    To guarantee manoeuvreability for wheelchair users within the bus stop platform, including entering and leaving a bus, a platform width (from end of ramp to back of platform) of 2.3 m was needed. The longitudinal space depended on the desired manoeuvres: at the maximum, provision for right and left turning onto and off the vehicle required a space 3.4 m long. If the platform was narrower than 2.3 m it was difficult for wheelchair users to enter the ramp or doorway at a straight enough angle and (in some cases) with enough momentum) to enable them to move easily onto the bus.
    Failure to achieve the correct approach resulted in a new attempt having to be made. This caused serious delays to the buses at the stop. There were serious problems with some older ramps. Several of the newer buses arrived with non-functioning ramps so these could not be tested. In any case the intention is to try to design the stops in such a way that ramps would only be necessary in relatively unusual circumstances because the horizontal and vertical gaps should be small enough to allow for most wheelchair users to manage without a ramp. This would be to the advantage of wheelchair users, bus passengers and bus operators. Problems were encountered by bus drivers in ensuring that the rear doors were correctly aligned to avoid obstacles, parallel with the kerb etc.. This is a particular problem in London where wheelchair users are expected to use the rear doors for entry and exit. This revealed the importance of detailed driver training for bus stops (and the usefulness of a facility such as this).
    The use of Kassel kerbs has been well known for some years. The EXCALIBUR experiments established that the approach angle of the bus was highly critical and had important effects on the platform length required to straighten the bus. Buses had to approach between 9 and 12 degrees n order to minimise the platform length. This is because of the ways in which the dynamic forces of the vehicle interact with the static forces of the kerb. Accordingly, a guidance system was developed to assist drivers in making the correct approach. The simplest system was to use a series of lines painted in the road at correct angles and positions so that the drivers could line themselves up for a correct approach to the stops. This is not unlike the concept of aircraft being positioned correctly for landing at an airport. It is important that drivers learn to position themselves correctly some distance before the stop and the guidance marks should help them to do this. Guidance lines set offside of the vehicle, with a target kerb identified by being constructed in a contrasting colour to act as a nearside guide, provided a good means of providing guidance towards correct positioning at a kerbside stop. However, difficulties were experienced with boarders. This is because, contrary to previous views held by bus operators and planners, a bus cannot simply drive straight alongside a boarder and achieve a horizontal gap of 50 mm. A lateral movement would be required of at least some 500 mm in order to reach the kerb in this way. Also, there is a need for the angle to be correct in order to obtain the guidance from the kerb. The difficulty of bringing the bus to the kerb at the correct angle when the lateral distance is so small resulted in the need for the platform to be longer at a boarder than at a kerbside stop (Although the total kerb length occupied by the bus stop including approach and exit paths is less for a boarder). A series of generic designs was produced for kerbside, half boarder, full boarder and bus bay stops. In a addition to the practical outcomes of the project, the mathematical modelling of this approach path and the impacts of the kerbs on the performance of the buses is underway and a generic theoretical model is being developed.
    These were then used to design a number of bus stops on the route 101 corridor in Newham Because of difficulties with the Borough, only two were constructed on street (a kerbside stop at Manor Park Station and a half boarder at East Ham
    Initial outcomes indicate that the stops work, with drivers, once trained, approaching the stops correctly and with a horizontal gap of between 0 and 100 mm with an average around 50 mm. The crossfall at Manor Park is too steep (an in situ alteration made during construction by the local authority) but otherwise the use of surfaces to indicate the doorways seems to help organise the passengers and ease the use of the buses at these stops.

Departmental Assessment Status: Project completed prior to implementation of Departmental Publication Scheme.