Abstract
As part of the discussion on whether daytime running lights (DRL) should be introduced in the Netherlands as a rule of conduct, arguments - pro and con - often relate to visual perception. Vehicles would be more conspicuous as a result of DRL, would be detected sooner and /or be better recognised, the distance to other vehicles could be better estimated, etc. Central to this report is the question of when "positive" and "negative" effects (relevant to visual perception) may be expected with DRL.