Effective Kerb Heights for Blind and Partially Sighted People

Several local authorities in the UK have redesigned town centres and high streets using the concept of shared space, or are in the process of doing so. Shared space aims to create shared ‘social’ areas for all users, reduce the dominance of motor vehicles and make streets more people-friendly.

Shared space is often delivered by means of a 'shared surface design' which requires the removal of the traditional vertical upstand (kerb). The removal of the kerb takes away the vital clue used by blind and partially sighted people to help them to navigate the pedestrian environment and to identify when they have reached the edge of the footway. In response to this The Guide Dogs for the Blind Association (Guide Dogs) has carried out or commissioned research both to establish the impact on the mobility of blind and partially sighted people and to examine potential approaches to delineating a 'safe space' in the shared space in which vulnerable pedestrians can move around with confidence. As part of that research programme, in 2007 UCL carried out trials with a range of potential delineators including a 30mm high kerb. In those experiments, it was found that a kerb height of 30mm was not sufficient to be reliably detected by blind and partially sighted people whilst remaining a barrier to progress for some wheelchair users.

Since some local authorities want to reduce the kerb height from the traditional 120mm and 30mm is too low, Guide Dogs asked UCL’s Accessibility Research Group to run tests to determine what kerb height could be reliably detected by blind and partially sighted people.