Barrier-free design of crossing facilities at local crossings of federal trunk roads

Sloped crossing system and use of visual contrasts

The aim of the research project was to develop cost-effective barrier-free crossing facilities for people with reduced mobility and at the same time to take into account the needs of cyclists. In addition, recommendations for different designs were to be made. It was important to bear in mind that different mobility impairments also mean different requirements for the design of kerbs. While wheelchair users, for example, prefer a zero drop kerb, blind people who use a long cane benefit from a clearly tactile kerb.

In order to achieve the objectives set, national regulations and research reports as well as designs of crossing facilities abroad were first analysed. Subsequently, road authorities in Germany were asked which barrier-free designs they have implemented to date and what reasons prompted them to choose a particular design. In order to assess acceptance, usability and possible difficulties or critical situations at differently designed crossing points, video observations of existing crossing facilities were carried out in several German cities. Five variants of a new design of barrier-free crossing facilities were then developed in workshops together with people with reduced mobility and then tested for practical suitability on a test track in the STUVA workshops. As a result, parameters for a barrier-free crossing facility were developed as a ramp without a kerb and recommendations for modifications and areas of application were made for different designs.

The tests clearly showed that in future, ramps as part of a crossing facility should generally have a maximum gradient of 10 per cent so that a clearly perceptible change in gradient is created for blind people, but the ramp can still be mastered independently by people with wheelchairs and rollators. The depth in the walking direction should be 100 cm. In addition, a ramp should be covered with visually and tactilely contrasting floor indicators and have a directional field with a ribbed structure in the main walking direction (in the form of a directional field in accordance with DIN 32984). It is important that the direction of the slope of the ramp and the direction in which the directional field is laid on the ramp (indication of the crossing direction) match so that the crossing direction can be reliably determined by blind and visually impaired people. The indicated crossing direction must therefore always be perpendicular to the carriageway axis of the carriageway to be crossed. Installation within a rounded corner is therefore ruled out.

The second part of the research project investigated how easily perceptible colour contrasts for people with visual impairments can be implemented at crossing points. To this end, various examples of the implementation of visual contrasts in public traffic areas were discussed in a workshop with stakeholders from the relevant groups (urban design, people with visual impairments, specialist administration) and both individual elements and urban spaces were considered and evaluated. The following basic design guidelines were then derived for the realisation of visual contrasts in public traffic areas:

There should be consistency between the design and the marking (e.g. edges with continuous longitudinal markings) and there should be consistency between the colouring of areas and the allocation of functions (demarcation of movement areas from other areas). The labelling of areas with different functions should preferably be done by area (in the sense of zoning) rather than as a linear demarcation. The experience of standardised elements or colour schemes (also typical of the region) should be taken into account. When using colours, the number of different colours should be kept to a minimum. Small-scale colour changes should be avoided. Design elements should be scrutinised with regard to their functionality as a guiding element and functionality should take centre stage in movement areas. Texture in particular can help to differentiate between areas of different colours, even if the visual contrasts are not ideal.