Impact of modern vehicle headlights on traffic signs.
Our vehicles have evolved – especially headlights.
Modern vehicle headlights are a world away from what they used to be.
Even in the last ten years, headlight performance has changed. This has impacted drivers’ visibility of street signs.
The University of Michigan Transportation Research Institute: headlight luminosity study.
A study conducted in 2019 by the University of Michigan Transportation Research Institute (UMTRI) gathered headlight luminosity data from headlights in 2019 model year vehicles. The findings were then compared it to a similar study conducted in 2011.
The research analysed how much light a variety of average light-emitting diode (LED) and tungsten-halogen (TH) vehicle headlights emitted. What researchers found was that low-beam headlights have evolved to produce less glare and deliver more light onto the roadway. Consequently, less light is angled towards street signs, affecting its visibility.
Key findings from the study: up to 20% lower sign illumination than vehicle headlights in 2011.
- Compared to 2011 TH low-beam headlights, 2019 models provide lower levels of illumination to typical roadway signs.
- 2019 median TH headlights, on average, result in 20% lower sign illumination than their 2011 counterparts.
- 2019 median LED headlights are about 14% lower than their 2011 counterparts.
- The reduction is more amplified for the 2019 lower quartile headlights. On average, 2019 headlights are 24% lower than their 2011 counterparts.
These findings mean that sign retroreflectivity may need to be increased to provide drivers with the same service level as in 2011.
A solution to increase roadway sign retroreflectivity.
Using a high-reflective prismatic sheeting in traffic signs can compensate for the evolution of low-beam headlights. The 3M™ Diamond Grade™ DG³ Reflective Sheeting Type XI offers reflectivity at short and long distances. It is our best solution for traffic signs that will serve the rapidly growing group of drivers of new cars.
Learn more about the 3M™ Diamond Grade™ DG³ Reflective Sheeting by contacting a 3M representative here.