A recent study conducted by the Monash University Accident Research Centre in Melbourne, Australia, found that vehicles fitted with automatic daytime running lights (DRLs) are statistically more likely to avoid a visibility-based crash than those without.
The study, published in the Journal of Safety Research, used police data from New South Wales, Victoria, Queensland, and Western Australia to estimate how much DRLs reduce the risk of being involved in a non-nighttime multi-car impact where visibility is a factor.
The study found that there was a "statistically significant" 8.8 percent reduction in risk associated with DRLs, with greater reductions seen at higher speeds and during dawn and dusk compared to bright daylight.
The data used in the study were police-reported casualty crash data for incidents that occurred from 2010 to 2017 (published online on February 8, 2023), with vehicle information obtained separately, including the VIN. This allowed the authors to determine which cars had DRLs using spec data, and cases where DRLs were offered as an option were removed.
In daylight conditions, the study found a reduction in crash risk of 7.6 percent associated with DRL fitment, whereas, at dawn or dusk, there was a reduction in crash risk of 20.3 percent.
Overall, DRL fitment was associated with a highly statistically significant decrease in crash risk of 8.8 percent, with the largest estimated relative risk reduction associated with DRL fitment being 23.8 percent for crashes at dawn or dusk in zones with posted speed limits above 47 miles per hour.
The study concluded that the results provide clear evidence that DRLs should be considered a mandate on all new vehicles. However, the authors noted that the magnitude of the potential reduction is likely to be smaller on average than the effect of some of the latest primary vehicle safety technologies currently available. There could be issues with timeliness, as well, seeing that the latest data was from over five years ago.
DRLs are already mandatory in many parts of the world, and there have been various studies proving their effectiveness in Europe and the US.