Two weeks ago, we discovered the report from IIHS about headlamp performance on US-model midsize cars. The results were very surprising to me, and I am working to understand such results, reading and re-reading the report, watching and re-watching the IIHS video. Why are so many headlamps rated “poor” with only one system assessed as “good”?
And why are so many European-brand headlamps assessed as “poor” when the main technologies were unveiled in Europe? I wrote last week, that we partly agree with the idea of testing the headlamps as delivered, without adjusting the aim. Drivers generally don’t know or care about how their headlamps are aimed. And I added, this can’t be the end of the discussion.
After poring over the report, I have three new comments.
1. In the video, we should have received information on how the tested headlamps were aimed.
Why such a difference of aiming between the Toyota Prius and the BMW?. I think the BMW was more than 0.5° lower than Prius, with its cutoff at 80 ft instead of 160 feet (see only the light on the trousers). This low aiming is amplified by the reading done at 10 inches from the ground instead at the level of the ground. Could the VOL beam pattern explain that? Or are the lamps aimed down to avoid glare because of the lack of an automatic levelling device?
2. Also in the video, I have trouble understanding such a big difference between the lighting effect of the two cars.
I often drive the BMW 3 Series with halogen. I do not remember such weak lighting (only because the aiming too low?) mainly on the right side.
Maybe the camera’s spectral response was more sensitive to blue (LEDs) than red (halogen)?
3. We must ask ourselves how and why despite so many innovations in lighting, and such strong efforts we are making in lighting, a test like this leads to the conclusion that most of the cars have poor lights in the US, at the opposite of European report conclusions.
We are continuing our investigations and we will regularly inform you about your feedback and our feedback alike. I am an independent expert, and I commit to do my best to totally understand this report.
I would like to ask you, DVN readers, to give your opinion about the IIHS report.
This week we’ve got an analysis by DVN General Editor Daniel Stern. In the next DVN newsletters, we will summarise and react to your feedback so the discussion is kept running, and we will have more public attention.
And the DVN Workshop in Tokyo next month will surely bring fruitful discussion and interesting anwers to the attendees.
Also this week, check out the DVN report on Geneva auto show, which you can preview with the snippets in this week’s Events news.
Sincerely yours
DVN Editor in Chief 