Development of an instrument to assess transport ability for people with low vision and limited mobility

• Main Author: Chan, Natalie
• Published: University College London (University of London) 2018
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.756313

This research project aims to develop an instrument that can measure the ability of people with low vision and/or mobility problems to use public transport. Focus groups were used to design a self-assessment instrument to help identify and measure existing problems with public transport navigation. Rasch analysis, an analytical technique used to convert ordinal difficulty ratings into interval measures, was used to validate the questionnaire. Difficulty ratings were calculated for each transport item and Transport Ability was calculated for each participant to develop a Transport Ability scale. The first survey included 22 public transport items and was applied to 414 people with various combinations of visual ability and mobility problems. The second survey included a further 24 transport items related to accessible transport modes and was applied to a further 308 participants, who had a combination of different visual ability levels and mobility aid requirements. The second validated instrument was then applied to three different case studies to investigate whether Transport Ability and Life Space score, which measures the extent and frequency of travel, could help to assess the effectiveness of transport schemes and skills training. The self-reported transport instrument developed in this study has demonstrated sufficient internal and construct validity to reliably measure the effect of Transport Ability for people with a combination of vision and mobility impairments. Principle Component Analysis of the residuals indicated that there were no other significant dimensions being measured. Overall, people with low vision and mobility aid users were found to experience lower Transport Ability and Life Space scores. However, the combination of both mobility aid use and low vision was not found to have a compounding effect on Transport Ability. Application of the instrument to transport accessibility schemes indicates that Transport Ability can be used to measure the benefit of schemes to individuals.