By on July 14, 2017

Dodge Durango Projector Headlights Aftermarket, Image: OP
TTAC Commenter flipper35 writes:

I thought I would give everyone an update on the lighting situation on the Durango. After considering the advice from both you and Mr. Stern, I decided that after all the expense of the new OEM lights, the better bulbs and the relay harness, I would just go with the more labor-intensive lights and less labor-intensive wiring from The Retrofit Source. I ended up spending a little over my budget but the lights are worlds better. They’re also an engineered solution that doesn’t blind other drivers.

I made an album with several pictures, before and after, with different settings. As you can see, on the new set there is a distinct cutoff on the “dims.” The low beams are currently adjusted a bit low and I haven’t taken the time to fix that yet, but on the road it is a major improvement. Other than a confused look from my wife when I had to bake the headlight buckets to remove the lenses and finding a place for the computer, ballast, and relay, it wasn’t too bad.

It was a little more work than I had planned, but the all-in price wasn’t much more than going the OEM route. It is a very significant improvement. I did get to adjust them a bit, and then followed my brother-in-law to see if they were blinding everyone. He said it was no different than other traffic, so I think I will leave the alignment right there. The beans line up on the door with the dims slightly higher than the other lights, but the old lights were sort of a blob on the top and I used a guess as to where the “cut” line was.

Thanks for all the help. I wanted to do it right and have them be able to align correctly. Even though I didn’t follow your exact advice, you gave me the push in the right direction. It still isn’t a bad looking truck for 190k miles!

Sajeev responds:

I can’t say I agree with your decision…but I’ve seen much worse.  Like mega-glaring aftermarket LED headlights with a non-existent cut line, lighting every rooftop (in urban areas) as they drive by.

My criticism of your retrofit is simple: 99.9% of the population can’t engineer a lighting solution with aftermarket bits never intended to fit behind your Durango’s lenses. From the photos I didn’t add (i.e. license plate), it seems you live in a more rural area, so that massively thick new hot spot certainly keeps you illuminated on a dark road in bad weather.

And the odds of anyone being bothered by that low-beam cut off is low. But is this retrofit in the spirit AND the letter of the law (so to speak)? 

The candlepower forums’ moderator brought up valid concerns in this thread. And since I got it last time, let’s bring in the wisest man on this subject, Mr. Daniel Stern to wrap this up.

Daniel Stern concludes:

Often, what we feel like we’re seeing isn’t what we’re actually seeing. The human visual system is a lousy judge of how well it’s doing. “I know what I can see!” seems reasonable, but it doesn’t square up with reality because we humans are just not well equipped to accurately evaluate how well or poorly we can see (or how well a headlamp works).

Our subjective impressions tend to be very far out of line with objective, real measurements of how well we can — or can’t — see. The primary factor that drives subjective ratings of headlamps is foreground light, which is light on the road surface close to the vehicle… and which is almost irrelevant. It barely even makes it onto the bottom of the list of factors that determine a headlamp’s actual safety performance. A moderate amount of foreground light is necessary so we can use our peripheral vision to keep track of the lane lines and keep our focus up the road where it should be, but too much foreground light works against us: it draws our gaze downward even if we consciously try to keep looking far ahead, and the bright pool of light causes our pupils to constrict, which destroys our distance vision. All of this while creating the feeling that we’ve got good lights.  It’s not because we’re lying to ourselves or fooling ourselves or anything like that, it’s because our visual systems just don’t work the way we feel that they work.

For that reason, the world’s headlamp technical standards and regulations for headlamps control foreground light as a proportion of the maximum intensity in the beam (the distance-vision “hot spot”). Many untested or fraudulently tested headlamps and components — at any price point — produce way too much foreground light: a strong wash of light close to the vehicle, but no (or not enough) concentrated hot spot to throw light down the road where you need it, so you get severely deficient seeing distance unless you aim the lamps up in the air… and then they blind everyone on the road, some of whom will write you tickets for it. Tip them down so you’re not glaring anyone, which you’re judging by the cutoff falling below other cars’ rearview mirrors? OK, but now the foreground’s even brighter while your seeing distance is sharply geometrically limited. Let’s do some math!

Regardless of the amount and distribution of light within the beam, by trigonometry the cutoff of a low beam mounted at a typical 2 feet above the road surface will intersect the road surface at:

282 feet ahead if aimed 0.7 percent down (the nominal U.S. spec)
197 feet ahead if aimed 1 percent down (the nominal European spec)
151 feet in front of the car if aimed 1.3 percent down
131 feet in front of the car if aimed 1.5 percent down
98 feet in front of the car if aimed 2 percent down
72 feet ahead if aimed 2.75 percent down

We can readily calculate our maximum safe speed if an obstacle appears at the end of our seeing range, assuming a realistic coefficient of kinetic friction of 0.6 between (decent) tires and (dry) road, and including the well accepted 2-second recognition and reaction time of a fully alert driver:

17 mph with lamps aimed 2.75 percent down
23 mph with lamps aimed 2 percent down
29 mph with lamps aimed 1.5 percent down
32 mph with lamps aimed 1.3 percent down
39 mph with lamps aimed 1 percent down (the nominal European spec)
51 mph with lamps aimed 0.7 percent down (the nominal U.S. spec).

What does this mean? Well, look at those low safe speeds even with lamps aimed at nominal specs. This is why so many of us gripe about our low beams not being adequate: they’re not! Their reach is limited by geometry, no matter the brightness. Most of us “overdrive” our low beams on a regular basis: we drive at speeds that require a longer view than our low beams can possibly give us. And remember, those figures are for a fully alert driver primed to encounter an obstacle at any moment. Most of us don’t maintain that kind of hypervigilance when we’re driving, so our reaction time is longer and our safe speeds are even lower.

The implications of all this:

Lamp aim is by far the main thing that determines how well you can (or can’t) see at night — it’s far more important than what kind of bulbs your headlamps have, whether they’re projector or reflector, European or U.S. type, etc — so see to it that the lamps are aimed carefully and correctly, not just by guess and by gosh.

By all means optimize your headlamps, but take the time to learn and understand what is and isn’t actually optimal.

Our eyes don’t inform us accurately how well our headlamps work, so most internet “reviews” are useless — and that would be the case even if we ignore the bogus criteria people often use when “reviewing” headlamps: sharp cutoff on low beam (very low on the list of factors that determine a headlamp’s actual safety performance, but it looks nifty on the garage wall), “E-code” (irrelevant; both the U.S. and the UN/”E-code” headlamp standards have lots of room for a huge range of headlamp performance), “high color temperature” (irrelevant at best)…and so on.

[Images: flipper35]

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16 Comments on “Piston Slap: A Stern Talkin’ to About OEM Headlamps (Part II)...”


  • avatar
    JimZ

    unfortunately, you try to explain to these “I know what I can see!” 20-year-old jagoffs that just because their OMG LOL blue HIDs aren’t helping them see better just because road signs are now dazzling, and all they do is natter “I’m not blinding anyone no ones flashed their brights at me cutoff, cutoff, cutoff.”

    sometimes I wish police would make more use of the non-vacatable improper equipment citation and start ticketing these people. *Especially* the people I see running those stupid “halo” lights in colors like red (illegal) or better yet, the one I saw where they were cycling through every color of the rainbow.

    I just wish I could find something to improve my 2011 Ranger’s terrible headlights. Bulbs ain’t the problem and what “retrofit” stuff exists out there looks like it’s all junk.

    • 0 avatar

      Re Ranger: I put GE Nighthawk bulbs (another Stern recommendation) in my stock lights and it made a big difference. The beam is wider and stronger, so I highly recommend, especially since they often go for cheap on eBay. ($20)

  • avatar
    rocketrodeo

    I worked for several years at a highway safety research institute, where my unit was concerned with night vision acuity and perception studies. I set up and maintained the testing platforms, which were SUVs with the stock lighting removed and some high-end Hella HID projectors installed on base plates that allowed us to test headlamps from a huge variety of manufacturers as well as a few aftermarket providers. Test vehicles were identically prepared, tire pressure and fuel load always the same, with headlamp aim laser aligned for each vehicle, each session. Measurement instruments used were the best available at any price.

    Without going into a long digression that would risk my confidentiality agreements, i’ll say that flipper35 is on the right track here *as long as he gets the headlamps aligned correctly.* Any shop with a Hoppy laser alignment system can do the job for any custom installation. If the projector module he is using is sub-par, the Hoppy will let him know. Well engineered projector modules vastly outperform all but a few reflector/refractor OEM lamps. A lot of that is because of outdated DOT specs that call for a certain amount of uplight for overhead reflector signs, which is a departure from the ECE standards that govern OEM-quality projector lamp design.

    I’ll also say that Mr. Stern’s work and reputation were not unremarked upon at said research facility, by a number of his peers, who can safely be regarded as the world’s foremost experts in vehicle lighting. It’s useful to remember that his missives support his sales efforts, not necessarily the state of the art. It is completely possible to safely engineer a vastly more efficacious and safer (for both the driver and oncoming traffic) lighting solution for nearly any vehicle, PROVIDED A CAREFUL AIM is part of the solution.

    • 0 avatar
      JimZ

      “It is completely possible to safely engineer a vastly more efficacious and safer (for both the driver and oncoming traffic) lighting solution for nearly any vehicle, PROVIDED A CAREFUL AIM is part of the solution.”

      except the numpties buying junk lighting products online aren’t “safely engineering” anything.

      • 0 avatar
        rocketrodeo

        Using the same modules the OEMs do is a good place to start. If you want better than that, I haven’t found many better than the Hella 90mm modules.

        My Y2K Ranger’s headlamps are actually adequate. I replaced them with OEM units few years ago when they started to degrade. Changing the bulbs every couple of years helps, too. Halogen capsules lose as much as 30 percent of their luminous flux in just two years, and much of that in the first six months.

  • avatar
    SkookumFord

    Looks good to me. More light up high and to the sides, but still below a cutoff that will glare other drivers. Good job. I for one encourage anyone who goes thru the effort to retrofit a good set of projectors rather than slap a set of HIDs in stock housings. Aim them right, and enjoy your hard work!

  • avatar
    PrincipalDan

    On the subject of headlights, I finally found a cleaning/de-hazing/defogging kit that I like.

    Wipe New Headlight Restore – it was pretty inexpensive, the name is cheesy, but it worked really well and only took me about a 1/2 hour.

    My headlights were the only part of my 2010 Highlander that looked “old” and it was driving me nuts.

    • 0 avatar
      rocketrodeo

      By the time the outer plastic lens has visibly oxidized, the internal reflectors are getting hazed as well. While it’s possible to clean them, really it’s better to just replace them. They aren’t terribly expensive.

  • avatar
    -Nate

    I too dislike the common pool on light right in front of the vehicle when what’s more important is what’s further ahead on dark roads .

    -Nate

  • avatar
    sportyaccordy

    I’m glad the OP took my suggestion!

    I’ve done a few retrofits and agree that as long as the aim is good you should be good. The only slippery thing is OEM HID setups have auto leveling systems that retrofits obviously don’t. In my Civic, the combination of my stiffer coilovers with the sharp cutoff make for a slightly annoying flicker. Shouldn’t be an issue with the Durango.

  • avatar
    Flipper35

    I know it is hard to see on the door, but I did tape off and measure the lights on low beam. I also parked on the road by the house to make sure they still shine far enough down the road. Now that Mr. Stern has given the specs I will go through the math to double check but I suspect they are pretty close given how they light the road compared to our newer vehicles.

    I should add, these did not get installed in the OEM diffused lenses, they are clear lenses on the buckets as you can see in the picture above.

    You may not be able to engineer a perfect solution with a retrofit but with projectors you can do a much better job than any other type of retrofit. In regards to the cutoff, and I know Mr. Stern knows how they work but some of you may not, there is no high/low beam. It is a single bulb with a shield that moves to cover the top. It makes a distinct cutoff which is good for glare for others on the road, but as noted not so good for overhead signs.

    By the way, those are 4500k color bulbs even though they look higher than that in the pictures. It wasn’t as dark when I took the after pictures and I think the auto white balance was off. On the road they look the same color as the 2014 Avenger lights.

    I knew that going this way would be controversial but for a similar price as OEM I still think these are a much better solution, even though it was more work. The only thing I got from eBay was the clear lenses for the buckets.

    I also need to add, I do respect Mr. Sterns opinion and did not take his advice lightly (no pun intended), nor Mr. Mehta’s advice.

    I had seen that post in the CP forum before and was part of the reason I was hesitant to go this way. There are a couple points there that are incorrect, but that is another post for another day.

    Now, on to those Bilstein shocks!

  • avatar
    Flipper35

    I should add, I was only using the rearview mirror test to verify I was not glaring in the mirror, not to set the alignment. The original alignment was set with a tape measure compared to the old. With the new math from Mr. Stern I can do it on the road by our house to be considerably more accurate.

  • avatar
    30-mile fetch

    Sajeev, thanks for posting this type of article. Very informative and so is rocketrodeo’s comment.

    This makes me grateful that I do very little driving at night outside of urban/suburban areas with lit streets. I can tell the stock headlights in both of our cars are nowhere near exceptional and correcting it appears to be complicated.

  • avatar
    hamish42

    My daughter bought a 2017 Nissan Micra, which is available here in Canada but not the US. She got the all singing all dancing one for 17.4K CDN (10.2K US) It isn’t’ bad – fits her needs pretty well but the headlights are totally unsafe. She had me drive it to be sure. What I have to find now is some after-market lights which are legal to use in Ontario. Most are too bright, but we’ll keep looking. This is a real flaw.

  • avatar
    seabrjim

    I have given up flashing my high beams at these idiots. When driving down 295 its amazing how many imbeciles “took the plunge” and “upgraded” to the blue OMG my chic digs em headlights.

  • avatar
    mcbacon

    When performed properly, I’m a huge proponent of HID/LED upgrades. I can’t stand PnP HID/LED kits simply for the dazzle factor. The ricer/ghetto blue headlight color temp actually REDUCES vision. Not only do the bulbs generally require a blue filter to produce that high-kelvin color (which reduces light output), blue is the harshest color for our eyes to process, and the extra blue glare makes it 10x harder on other drivers. I personally don’t care if someone retrofits their headlamps, but please do it properly!

    Purely anecdotal, take the Mk4 Jetta (Bora)/Golf. While their halogen lights are worlds better than the terrible DOT only domestic setups of the time, they still leave a lot to be desired. When replaced with a proper HID bi-xenon projector and properly aligned, even the pitch black rural roads on which I used to live became better.

    Personally, I prefer a slightly higher color temperature. Sure, you get a bit more light from 4300k, but 5000-5500k is easier on my eyes. UNlike some, I also don’t like a super-sharp cutoff. Using a fresnel lens instead of a clear lens gives a more diffuse cutoff which I find to be easier on my eyes, too. Sure, you lose the hella cool wall shot and the pretty color flicker, but I don’t care about that.

    OEM headlamp efficacy has definitely improved in recent years, but they still frequently leave a lot of performance on the table because most OEMs are concerned with meeting standards at a low price and not outright performance.


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