A new study has concluded that daytime running lights, or DRLs, can slow pedestrians’ reaction times to turn signals. On 7 February 2011, the European Commission made it a requirement for all cars being put forward for type approval, to have DRLs. However, researchers at the University of Granada have found that such lights can render turn signals ambiguous.
Previous studies have demonstrated the effectiveness of DRLs in reducing the number of road accidents in which vehicles collide with pedestrians. Whilst the new research does not question the validity of these findings, it does suggest that DRLs make a car’s turning signal less clear during daylight hours.
The study, led by Professor Antonio Peña García, investigated whether DRLs could be responsible for masking turn signals. The experiment was conducted outside during daylight hours to mimic the conditions under which DRLs are used. It found that both the colour of a DRL and the angle from which it is perceived, directly affect a pedestrian’s reaction time to turn signals.
Ambiguity over turn signals however, might be the price paid for improved visibility. According to research quoted by the European Commission, road users find it easier to detect vehicles equipped with DRLs, than those using traditional dipped-beam headlights. Even so, as DRLs become the norm on European roads, perhaps more work can be done to ensure that pedestrians do not receive mixed signals.