London Underground Driver testing
Based on the results of this study, TfL designed a colour assessment protocol based exclusively on the CAD test. The new approach to colour assessment ensures that up to a third of people who would have previously been prevented from working as train drivers are now passed fit.
At TfL, the safety critical part of a train driver’s assessment is red/green vision – a number of coloured light signals of well-defined spectral composition are involved. Blue/yellow vision is also important and is part of the assessment to check for eye health.
A detailed description of how the CAD test is used in the TfL environment is given in an article written by John Ballard (Editor, Occupational Health at Work Journal).