anyone ever get a headlight ticket?
Yes, DRLs—legitimate ones, configured appropriately for automatic operation—significantly reduce your risk of being in a crash during the daytime, and are required equipment in Canada, throughout Europe, and in a large and growing number of other countries throughout the world because they are a very cost-effective safety device (i.e., they work). The safety benefit from thoughtfully-done DRLs is real, but some implementations of DRLs introduce safety-negative effects that can cancel or, in extreme cases, reverse the safety benefit.
Most arguments against DRLs, whether or not their exponents realise (or admit) it, are arguments against
the problems caused by particular implementations of DRLs, not against the concept itself. And unfortunately there are a lot of bad kinds of DRL allowed in North America. Example: here's a photo of one of the original factory-installed 9005 high beam bulbs I removed last week from a 2014 car I bought last month (~69k miles). As on many vehicles in Canada + USA, the high beams are operated at 50% rated voltage to provide 10% rated light output for the daytime running light function:
The underdriven bulbs don't get hot enough for the halogen cycle to occur—by which tungsten boilt off the filament is scavenged off the bulb wall and re-plated onto the filament—so unless the full-power high beams are periodically used for long enough to clean up the bulb, the tungsten accumulates on the bulb wall, at first forming a red-brown stain and eventually blackening it. This makes the glass absorb more heat, and by and by it begins to melt and a blister is blown by the bulb's internal pressure of several atmospheres. Meanwhile, output drops enormously because black opaque stuff in the way. But the lamps keep on lighting up (after a fashion…good luck seeing anything; lookit that shadow on my kitchen table!)
More babble on the topic if anyone wants it, but in case not, I shaddup now.
Yes, DRLs—legitimate ones, configured appropriately for automatic operation—significantly reduce your risk of being in a crash during the daytime, and are required equipment in Canada, throughout Europe, and in a large and growing number of other countries throughout the world because they are a very cost-effective safety device (i.e., they work). The safety benefit from thoughtfully-done DRLs is real, but some implementations of DRLs introduce safety-negative effects that can cancel or, in extreme cases, reverse the safety benefit.
Most arguments against DRLs, whether or not their exponents realise (or admit) it, are arguments against
the problems caused by particular implementations of DRLs, not against the concept itself. And unfortunately there are a lot of bad kinds of DRL allowed in North America. Example: here's a photo of one of the original factory-installed 9005 high beam bulbs I removed last week from a 2014 car I bought last month (~69k miles). As on many vehicles in Canada + USA, the high beams are operated at 50% rated voltage to provide 10% rated light output for the daytime running light function:
The underdriven bulbs don't get hot enough for the halogen cycle to occur—by which tungsten boilt off the filament is scavenged off the bulb wall and re-plated onto the filament—so unless the full-power high beams are periodically used for long enough to clean up the bulb, the tungsten accumulates on the bulb wall, at first forming a red-brown stain and eventually blackening it. This makes the glass absorb more heat, and by and by it begins to melt and a blister is blown by the bulb's internal pressure of several atmospheres. Meanwhile, output drops enormously because black opaque stuff in the way. But the lamps keep on lighting up (after a fashion…good luck seeing anything; lookit that shadow on my kitchen table!)
More babble on the topic if anyone wants it, but in case not, I shaddup now.