[Open Discussion] Pros & Cons of Daytime Running Lights and Aux Lighting on all the time

Dean

Adventurist
Founding Member
Let's face it, the light-bar trend is here to stay. Before light-bars it was big ol' round KC lights. Auxiliary lighting has always been a part of the off-road scene for both functional and aesthetic reasons. Lately the OEM industry has, for better or worse, been required to add Daytime Running Lights to all newer vehicles. That seems to have furthered the habit of people running light-bars (or other aux lighting) during the day "in the name of safety."

Without starting too much of a pissing match, what are the pros and cons with DLR's and other aux-lighting all the time? Are there times when its more detrimental than helpful? Are some lights acceptable for running all the time? Are some lights totally inappropriate all together?

I know there are a lot of opinions, old wive's tales, and bad advice out there. so I'm hoping for a serious discussion backed by some actual experience and even science if possible.
 
Two of the most important factors for me when I select aux lighting are temperature and beam pattern:

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I have found, in my experience, a driving or fog beam with an amber cover has been the best investment I ever made. I run a Rigid High/Low Dually which seems to work great on-road (on low) and off-road (on high). In the three years I've run them I've never been in a situation where I've needed to take the amber covers off. I find they offer great contrast in dust, snow, fog, rain, and even smoke. I also think they increase my visibility in inclement conditions without blinding oncoming drivers.
 
Biggest con is lights that are not designed for on-road driving. I am sure they work great for the user, but are a detriment to others (and often illegal).
This is the real issue.

DRL's have been around for a long time, and work really well IMO. It was my understanding they were not required in the US until relatively recently (I could be very wrong!). But I really like the ones on my 4runner, pretty bright and very orange. Makes it quite visible.

Now the light bars is a whole 'nother issue.... My God does it drive me nuts. And the influx of cheap Chinese bars has not helped. $30 for endless light sprayed everywhere is affordable by most anyone that wants it! Yay! Its absolutely terrible for oncoming traffic, and probably makes your night vision worse with the foreground splattered with high intensity light.... /rant off.
 
Baja Designs has said they are coming out with DOT approved lights for on-road use. Rigid already has them. I have the Rigid DOT approved lights that replaced my fog lights, and they are adjusted so the cutoff is about license plate height on a car. I run them all the time. But my lightbar stays off until I'm offroad AT NIGHT and no one is in front of me. It's just rude and stupid to run that on streets.
 
Baja Designs has said they are coming out with DOT approved lights for on-road use. Rigid already has them. I have the Rigid DOT approved lights that replaced my fog lights, and they are adjusted so the cutoff is about license plate height on a car. I run them all the time. But my lightbar stays off until I'm offroad AT NIGHT and no one is in front of me. It's just rude and stupid to run that on streets.
I too have the Rigid DOT/SAE fogs. Great lights and I use them often when dark as the standard headlights leave a bit to be desired. I got flashed a few times and was concerned that my aiming was bad, to the point that I parked in the street at night and drove towards them in a different vehicle. My theory is that the color difference was significant enough between these and the 25 year old factory headlight design that people just thought the contrast meant I shouldn't have them on. There was zero glare that should upset another driver. I added an amber covers though, partially for stone protection, and haven't had an issue since.

Regarding DRLs, it seems like they are a good idea. The newer interpretation of LED accents serving that function is interesting when the turn signal cancels them out on the turning side. It looks like one of the lights is burned out, but if that helps bring attention to a turning vehicle, that's okay.

Regarding turn signals, that is a significantly underutilized light. :worms

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...concerned that my aiming was bad, to the point that I parked in the street at night and drove towards them in a different vehicle.View attachment 42225

I think it depends on what the "different" vehicle is. I rarely notice oncoming lights when I'm driving my truck, but when I'm in my wife's RAV4, they all bother me. I am not a fan of any extra lighting
 
I think it depends on what the "different" vehicle is. I rarely notice oncoming lights when I'm driving my truck, but when I'm in my wife's RAV4, they all bother me. I am not a fan of any extra lighting
Good point, the lower the driver, the more they will be in-line with a cutoff. These fogs are aimed below the factory headlights and pretty well defined. The few times I was flashed I noted also that I was cresting a hill and it was vehicles coming up, so they were definitely underneath. Would have been the same for factory fogs, of which the Japanese never offered in this model (just lots of switch blanks).
 
I'm trying to avoid the use of the blue 6000K lights and stick to the yellow 4000K. The human eye is more sensitive to yellow/green. It's also why I put a PIAA Plasma Ion Yellow on the motorcycle for the headlight

From: https://www.olympus-lifescience.com/en/microscope-resource/primer/lightandcolor/humanvisionintro/

"In recent years, consideration of human color visual sensitivity has led to changes in the long-standing practice of painting emergency vehicles, such as fire trucks and ambulances, entirely red. Although the color is intended for the vehicles to be easily seen and responded to, the wavelength distribution is not highly visible at low light levels and appears nearly black at night. The human eye is much more sensitive to yellow-green or similar hues, particularly at night, and now most new emergency vehicles are at least partially painted a vivid yellowish green or white, often retaining some red highlights in the interest of tradition.

and

"Human visual perception of primary subtractive colors, such as yellow, can arise in one of two ways. If the red and green cone cells are simultaneously stimulated with monochromatic yellow light having a wavelength of 580 nanometers, the cone cell receptors each respond almost equally because their absorption spectral overlap is approximately the same in this region of the visible light spectrum.​


From: https://visual.ly/blog/the-use-of-yellow-in-data-design/

"The Opponent Process Theory of Color
Here’s how your brain takes the signals of light intensity from the cones and turns it into color information. To see red or green, your brain finds the difference between the levels of excitement in your red and green cones. This is the red-green channel. To get “brightness,” your brain combines the excitement of your red and green cones. This creates the luminance, or black-white, channel. To see yellow or blue, your brain then finds the difference between this luminance signal and the excitement of your blue cones. This is the yellow-blue channel.
image_03.png

From the calculations made in the brain along those three channels, we get four basic colors: blue, green, yellow, and red. Seeing blue is what you experience when short-wavelength/high-frequency light excites the blue cones more than the green and red. Seeing green happens when light excites the green cones more than the red cones. Seeing red happens when only the red cones are excited by long-wavelength/low-frequency light.

Here’s where it gets interesting. Seeing yellow is what happens when BOTH the green AND red cones are highly excited near their peak sensitivity. This is the biggest collective excitement that your cones ever have, aside from seeing pure white. Notice that yellow occurs at peak intensity in the graph below. Further, the lens and cornea of the eye happen to block shorter wavelengths, reducing sensitivity to blue and violet light. This, combined with the neuronal nirvana resulting from the overlapping sensitivity of the red and green cones, is why yellow appears to be the brightest color in the spectrum, making it a unique and useful color.
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I really like DRL's. Safety is paramount especially out on the road. Low visibility conditions and distracted drivers... we need all the help we can get to stand out against the surroundings.

On my Baja Designs LP9's I like to run the yellow fog accents all the time, really makes the vehicle visible in all conditions. Not for bling, but to stand out and be seen.

But I really dislike yahoos running their light bars and other retina searing LED's on the road needlessly. No need for that unless you are WAY out in the forest or desert alone - I like the long distance of the LP9's when watching for jihad deer :D
 
I also run the Rigid fogs and they have been phenomenal with their distinct cut-off and illumination. As tall as my truck is I haven't been flashed by oncoming traffic; perhaps their slightly outboard mounting helps, vice straight ahead.
 
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