On Sun, 29 Sep 2019 13:59:17 -0600, rbowman
wrote:

On 09/29/2019 01:03 PM, wrote:
I wondered that also.
All our friends & family's cars & trucks, since ~ early 1990's
have had them - with no problems .

DRL's are more common in the US but I was once stopped by a cop who
noticed the headlights were on but no taillights. He assumed I had
defective taillights. I'd also had regular people tell me the taillights
weren't working.

I don't know if it was state or federal laws but since the '80s
motorcycles have has always on headlights. These aren't reduced output
DRL's, just the normal headlights. The effectiveness of the increased
visibility in reducing accidents was studied extensively.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4771245/

I do not know if there ware follow up studies after mandatory DRLs were
introduced in Canada and other countries. My current Toyota does not
have them but my previous 2007 version of the same model did. That's
surprising since car makers have tended to include anything that is
required anywhere in the world and submit the bill to the purchaser.
There is no "bill". It's a few lines of computer code today.