Philips LED DRLs. Legal? Any good?

I came across these, and they look good. Philips is one of the big reputable lighting companies, and they even show them photoshopped on to a BMW! Kidding aside, they indicate that they are DOT compliant rather than "certified". What are the complications associated with adding DRLs to a vehicle?

"Compliant" is a perfectly fine word here, meaning the same as "certified" in every respect. Though if you didn't know that it's wise to question it since some words ("approved") are really not applicable. The Philips aftermarket DRLs are nice pieces, meeting both the US and European technical standards. Some models of them have dual intensity (dim for parking lamp mode, bright for DRL mode). I can't think of anything bad to say about them, and they are legal. The biggest/only complication is how and where to mount them on your particular car. They need to face front (obviously) and they should be as far apart from each other as possible.

electromage said:

they indicate that they are DOT compliant rather than "certified". What are the complications associated with adding DRLs to a vehicle?

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Scheinwerfermann said:

"Compliant" is a perfectly fine word here, meaning the same as "certified" in every respect.

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It's the same in the computing world. A card can be PCI 2.2 "compatible", but if it's not PCI 2.2 compliant, it can cause problems (and ones that can be hard to track down).

DOT doesn't approve automotive lighting fixtures, it just writes regulations and certifies manufacturers that are capable of building compliant lighting fixtures. So the question is, are the lights actually in compliance with DOT regulations? If so, great. If not, you'll probably never get caught, but please don't use them unless you can be sure the lights are actually better than DOT regulations require (e.g. European headlights, which don't comply with DOT beam patterns but are actually quite a bit better). It's not just about your safety, it's also about the safety of the people you'll blind on dark roads.

That being said, DRLs are for location-marking only, and provide no meaningful beam-projection, so glare is basically a non-issue day or night. They simply aren't bright enough to blind anyone, much like taillights or side markers, so even though they're built into the headlamp, it's entirely possible that DOT might not have any regulations at all for DRLs.

fyrstormer said:

DOT doesn't approve automotive lighting fixtures

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Correct.

it just writes regulations and certifies manufacturers that are capable of building compliant lighting fixtures.

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Not correct. DOT does not certify manufacturers. In the US regulation system, the manufacturer or importer of a vehicle or piece of vehicle equipment self-certifies that the vehicle or equipment complies with applicable provisions of applicable regulations.

So the question is, are the lights actually in compliance with DOT regulations?

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Already answered: Yes.

lights are actually better than DOT regulations require (e.g. European headlights, which don't comply with DOT beam patterns but are actually quite a bit better)

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Not correct. There is ample (I would say excessive) room in the US and the EU lighting regulations alike for poor lights. There are good DOT lights and bad ones, and there are good EU lights and bad ones. The idea is common but false that a vehicle light built to comply with EU regulations is necessarily better than one built to comply with US regulations. Extensive discussion (and quarrelling) on the subject can be found starting at post #13 in this thread among others.

DRLs are for location-marking only, and provide no meaningful beam-projection, so glare is basically a non-issue day or night. They simply aren't bright enough to blind anyone

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This is also not correct as stated. US and Canadian regulations allow DRLs to emit up to 7000 candela when tested at the specified system input voltage of 12.8 volts. 7000 candela is quite glaring, and operating voltage is usually quite a bit higher than the test voltage; it is common to see system voltage of 14.2 to 14.5. An operating voltage of 14.2 volts makes incandescent DRLs over 42% brighter than their intensity at 12.8v, that is nearly 10,000 candela -- definitely glaring. Thousands of complaints have been filed with NHTSA about DRL glare, and while many of them are pretty incoherent and ignorant in their content, the basis of the complaint is valid.

EU regulations cap DRL intensity at 1200 candela, a figure which can only cause glare under very unusual circumstances. The allowable axial intensity range for the US is 500 to 7000 candela, and the allowable range for the EU is 400 to 1200 candela, so most DRLs compliant with ECE Regulation 87 are also compliant with the US regulations.

even though they're built into the headlamp, it's entirely possible that DOT might not have any regulations at all for DRLs.

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That is also not correct. DRL regulations in the US and Canada are considerably more permissive than EU DRL regulations, but the North American regulations definitely exist, and while DRLs are not mandatory in the US, if they are installed they must comply.