Kassel kerb

A detail look at a Kassel kerb. Note the rounded section which allows the tire to ride up and realign itself.

A Kassel kerb is a concave-section made for buses kerb stone which is intended for use at bus stops served by modern low floor buses which have improved accessibility for mobility-impaired people. The Kassel kerb takes its name from the German city of Kassel, where it was first introduced.

Kassel Sonderbord

In 1996 the DIN German Institute for Standardization issued the DIN 18024 part 1 ("Barrierefreies Bauen - Teil 1: Straßen, Plätze, Wege, öffentliche Verkehrs- und Grünanlagen sowie Spielplätze; Planungsgrundlagen" / Barrier-Free Design - Part 1: Streets, Places, Roads and Recreational Areas; Planning Basics) that was updated in 1998. Kassel had been on the forefront with performings tests with low-floor busses as early as 1992. A simple increment on the bus platform height however showed problems with wear on the bus tyres - the planning department of the Kassel Public Transport Company began to assemble ideas on a "special curb" (giving the name "Sonderbord") for their bus stops since 1994. A manufacturer was found in the company Fröhlich Bau AG in Gesungen south of Kassel with their patent kerbstone (EP0544202/1993). After its termination the manufacturing was taken over by the company Profilbeton GmbH in Borken, Hesse (also south of Kassel). Up to 2001 about 1/6 of the bus stops in Kassel had been converted to the "Kasseler Sonderbord" product.

The function of the Kassel kerb is to guide the tyre of the stopping bus in a such a way as to improve the alignment of the bus's doors with the kerb and slightly raised boarding platform. It does this because as the tyre rides up the concave surface, gravity pulls it back down and steers the bus into alignment.

The Kassel kerb stone has become a common design element in contemporary bus stop design - the provisions of the DIN 18024-1 have been proposed in 2010 to become a section of DIN 18070 („Öffentlicher Verkehrs- und Freiraum“ / Public Transport and Open Spaces).

Dresden Combibord

Dresden „Combibord“ kerb on a tram platform

The "Dresdner Combibord" kerb is a parallel development being derived from the elevated sidewalks used for low-floor trams in Dresden, Germany. Its development started during the introduction of the first low-floor trams (mode Gelenktriebwagen NGT6DD during 1995-1998) and the Combibord patent was granted in July 1997 (DE 19730055). The round section allows busses to align to the tram platform in a similar way as the trams for level entry.

The Dresden Public Transport Company gives the following reference data:

• platform height at the doors of the trams at least 23 cm
• platform height at the doors of the busses at least 18 cm
• remaining entry height from platform to trams at most 5 cm
• remaining entry height from platform to busses at most 8 cm
• remaining gap between platform and trams/busses at most 5 cm
• on dedicated tram stop platforms an accessibilty from public sidewalks is asserted with a maximum ramp elevation of 3 cm and incline below 6%

Variants

• The Erfurt Busbord kerb is deployed since 2007 with a height of 24 cm. (the kerb in Kassel has been 18 cm).
• The Berlin Combibord kerb has a height of 21 cm above rail (the kerb elements in Dresden have a height of 24 cm above rail).