Hugo Bruggeman 3M Company St. Paul Transportation Safety Division Laboratory
History of Vehicle Headlamps in Europe (ECE) Halogen H4 Diffuser Lens 1000 Lumen
LED Projector Lens 2000 Lumen
© 193M April 2022 . All Rights Reserved.
Halogen H7 Reflector Type 1500 Lumen
HID (Xenon) Projector Lens 3200 Lumen
History of Vehicle Headlamps in Europe (ECE)
Typical ECE passing beam light distribution / HID Projector Lens / Model Year 2015 © 193M April 2022 . All Rights Reserved.
History of Vehicle Headlamps in the US
‚Visually Optically Aligned‘ VOA headlamp with sharp ‚cut-off‘ line, similar to ECE headlamp > Significantly less illumination for traffic signs © 193M April 2022 . All Rights Reserved.
Vehicle Trends in Germany and US SUVs • In 2021, 25% of new vehicle registrations in Germany are SUV • 56% of US Vehicles are Trucks / SUV
© 193M April 2022 . All Rights Reserved.
LEDs • In 2021, 8 of 11 of Germany’s best selling vehicles come standard with LED Headlamp (Source: Kraftfahrtbundesamt) Rank
Model
Headlamp (standard)
Type
1
VW Golf
LED
Car
2
VW T-Roc
LED
SUV
3
VW Tiguan
LED
SUV
4
Opel Corsa
Halogen
Car
5
VW Up
Halogen
Car
6
VW Passat
LED
Car
7
Mini
LED
Car
8
BMW 3 Series
LED
Car
9
Skoda Octavia
LED
Car
10
Fiat 500
Halogen
Car
11
Tesla Model 3
LED
Car
Legibility of Retroreflective Traffic Signs
© 193M April 2022 . All Rights Reserved.
Change in Headlamp Light Distribution • Passing Beam > 2019 LED lamps illuminate the roadway at higher levels than 2011 lamps • LEDs reduce illumination of typical sign positions while minimizing glare to other users on the roadway 2011
© 193M April 2022 . All Rights Reserved.
2019 -LED
Contour plots of Log2 transformed luminous intensity distributions (log2*cd)
Impact of LED Headlamps on Sign Legibility • How much have sign illumination levels changed over the past decade?
• Is the change different for the 2019 LED lamps vs compared to the 2019 Halogen lamps? • To analyze this, we ran simulations for UMTRI 2011 and 2019 matrices (25%tile) with prismatic retroreflective sheeting conforming to ASTM D4956 Type XI standard UMTRI Report: https://deepblue.lib.umich.edu/bitstream/handle/2027 .42/154777/UMTRI-2019-5.pdf © 193M April 2022 . All Rights Reserved.
3M Research Synopsis: https://multimedia.3m.com/mws/media/1775333O/lo w-beam-headlight-study-summary.pdf
Change in Headlamp Light Distribution Circles mark the location where signs are positioned • Overhead • Left shoulder • Right shoulder
© 193M April 2022 . All Rights Reserved.
2011
Change in Headlamp Light Distribution Circles mark the location where signs are positioned • Overhead • Left shoulder • Right shoulder
© 193M April 2022 . All Rights Reserved.
2019 LED
Traffic Sign Illumination US Beams 2011
• Similar illuminance curves for different vehicle types • Sign illumination levels increase during approach • High illumination levels for right shoulder sign • Low illumination levels for overhead sign
© 193M April 2022 . All Rights Reserved.
Distance: 180m
150m
120m
90m
Reduced Illumination Levels for 2019 headlamps
…especially for Halogen lamps
Distance: 180m 150m 120m 90m © 193M April 2022 . All Rights Reserved.
180m 150m 120m 90m
180m 150m 120m 90m
Retroreflection and Vehicles VW Tiguan II vs. VW Golf VIII
• more intensity in the center of the cone • larger vehicles receive less light • SUV and Truck Drivers in a disadvantaged position
© 193M April 2022 . All Rights Reserved.
Traffic Sign Luminance Curves for 2011 A driver of a sedan or light truck benefits from increasing luminance levels A driver of a heavy truck may suffer from decreasing luminance levels Luminance curves for a heavy truck are decreasing because its driver is seated further above the headlights which is a disadvantaged position (larger observation angle).
© 193M April 2022 . All Rights Reserved.
Distance: 180m
150m
120m
90m
Lower Luminance Curves for 2019
…even worse for Halogen lamps
Distance: 180m 150m 120m 90m © 193M April 2022 . All Rights Reserved.
180m 150m 120m 90m
180m 150m 120m 90m
Traffic Sign Legibility - 2011 vs 2019 Lamps • People differ in their luminance "needs" or demands. • People who benefited from the increasing luminance levels under 2011 lamp illumination may find it more difficult to read signs under 2019 lamp illumination. • In some cases, the change to lower luminance levels may mean that a driver is no longer able to read a sign under 2019 lamp illumination.
© 193M April 2022 . All Rights Reserved.
Conclusions • Lower levels of traffic sign-illumination for 2019 headlamps compared to 2011 headlamps • Reduction may adversely impact drivers who have higher luminance needs, including some of the elderly drivers • Reduction is somewhat less for LED lamps than for Halogene lamps
© 193M April 2022 . All Rights Reserved.
Conclusions Road administrations may consider upgrading to Class 3 retroreflective traffic sign sheeting in Full-cube technology The higher levels of retroreflection combined with the wider cone of retroreflection of full cube sheeting may mitigate the impact of the reduction in sign illumination with LED lamps 2011
© 193M April 2022 . All Rights Reserved.
2019 -LED
Thank You Visit us at Intertraffic Amsterdam 29 MAR – 1 APR 2022, Hall 1, booth 01.253