A literature review was made to study whether the ability to distinguish between colours was important for the occupational functioning of a driver in urban public transport. The study was required for the public transport company in the hague, because there were rules for recognising colours for tramway-drivers, but not for bus-drivers. There is a difference, which can not be explained sufficiently, between the results from experimental studies (increased risk) and from accident studies (no increased accident figures). These studies are each critically discussed. There is no homogeneity in the international requirements. In a number of restrictive conditions it seems to be the case that tram or bus-drivers with an impairment in distinguishing colours can do their job if (1) the driver knows his impairment (2) there are good traffic psychological tests (3) a successful test is carried out in practice and (4) the light signals fulfil the international CIE specifications.
Abstract