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Discussion Starter · #1 ·
The standard halogen projector headlights on the Impala rely on a single light source with a shutter to control switching between high beam and low beam -- a method more normally reserved for HID installations. The problem with the system is not so much the intensity of the light produced (which is not great, marginal in rainy conditions), but its beam distribution. On both high and low beams very little light is dispersed to the front sides of the vehicle and on high beam the long distance component of the light is very narrow -- approaching a pencil like distribution with limited scatter to the sides. This means that sharp right turns are very tricky (you cannot see the side of the road to the right as you make the turn) and any pedestrians to the side of the vehicle at an intersection are in near darkness, making night driving an unnerving experience.

I believe this represents a serious safety concern, and have registered an entry on the NHTSA Vehicle Safety site in the hope that this receives attention (ODI number 10651739). The dealership has checked the lights twice and tells me that they are performing as designed.

A fix may be as simple as redesigning the projector lens to throw more light to the sides of the vehicle or installing supplemental cornering lights, but ideally the system should have a stronger light source too. The status quo is not satisfactory and potentially unsafe. With so much riding on an otherwise excellent and modern vehicle, I hope GM is responsive in addressing this issue with a design change and a speedy recall to fix the existing fleet.
 

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Fog lights?

Hate to tell you but the lights likely preformed well and passed the lighting tests.

Have you tried adjusting the passenger light a little bit to the right? Projector lenses are much better than the regular at focusing light. A tip is if the road is marked is to just follow the divider line instead of trying to see the curb. Easier to see regardless.
 

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Discussion Starter · #3 · (Edited)
Thanks for the reply. My baselines for comparison are my wife's 2003 Malibu and a recent 2014 Impala rental (actually the previous Impala design continued for 2014 as a fleet-only model). The halogen lights on both of these perform much better -- stronger light, better light dispersal. I raise this as a safety issue after finding other posts identifying similar concerns. Here's one relevant link -- see items under "Exterior Lighting":

http://www.arfc.org/complaints/2014/chevrolet/impala/

Perhaps the design does meet the letter of the regulations. I'm not in a position to comment on that but do have concerns about the real-world performance of the units. Tests are not infallible and may fail to identify issues that are very apparent in a few minutes of night driving on twisty roads or at dark intersections.

Thanks for your suggestions. Integrating fog lights into the clean front end design would be tricky. For some reason integrated fogs are not a factory option. I am, however loathe to make aiming changes that would ruin the straight ahead performance and take the headlights out of design spec. If there is a design issue isn't it better that it is addressed by the manufacturer?

I think the Impala is a great car and want it to succeed. I hope that GM steps up to the plate on this.
 

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In its automobile road tests, Consumer Reports evaluates headlamp performance for all vehicles. Here are notes for a couple recent General Motors vehicles:


  • 2014 Impala LTZ with bi-xenon (HID) headlamps: "The low- and high-beam HID (high-intensity discharge) lamps provide good levels of forward and sideward visibility, but they don't have the very bright, white light you might expect from HIDs. That may be good for the drivers of oncoming vehicles, as they may not be annoyed by glare. But it could be disappointing to a driver who expects them to be brighter. The HIDs are standard on the LTZ trims, and include a decorative strip of LED lights as daytime-running lamps. Lower trim levels have standard halogen bulbs."
  • 2014 Buick Regal Premium I with bi-functional halogen headlamps: "Low beams not only lack intensity but what light they provide does not illuminate a sufficient distance ahead to allow the driver time to see and react to anything ahead in the road. High beams also lack the seeing distance compared to most vehicles. To make matters a bit worse, the beams' pattern is also a bit streaky, with each beam separately visible in what should be a fairly uniform pattern of light. HIDs are standard on the higher Premium II and GS trims. If you drive frequently at night, the HIDs might be worth considering as they provide much brighter light and better overall visibility."

The bi-functional halogen headlamps on the Regal, using HIR2 bulbs, are very similar to those found on MY 2014+ Impala LS and LT models. It seems the optics for these bi-functional halogen units are not designed optimally. You did the right thing in submitting your complaint to NHTSA.
 

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This means that sharp right turns are very tricky (you cannot see the side of the road to the right as you make the turn) and any pedestrians to the side of the vehicle at an intersection are in near darkness, making night driving an unnerving experience.
What ever happened to turning lights that would turn on with the turn signal? Cadillac had them and we even had them on our Catera.
 

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Discussion Starter · #8 · (Edited)
Why have bi-functional halogens? Surely the extra cost of double-filiament lightbulb (like a 9003 or an H4) is essentially zero compared to the shutter...
Perhaps GM thought it could go with the same streamlined housing for both halogen and HID applications to allow a consistent front end appearance, shared components and reduced cost. Whatever the thinking, it's not working in practice. Don't the specialists at GM do extensive real world testing in addition to performing static tests?
 

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Discussion Starter · #10 ·
As lighting is one of the most important safety features on a car, I'd rather retain my faith in human nature and not subscribe to that view. I think its a case of poor design, inadequate testing, an "it's good enough" mindset, and negligent managerial oversight.

In the age of global competition, where companies like BMW sweat every detail, "just good enough" just isn't good enough.
 

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maybe the idea is to make the standard lights as terrible as legally possible so that people will spring for the HID option

kind of like how any car with hubcaps, the hubcap is a terribly ugly and unappealing design so people buy the mags...
I previously owned a 2012 Impala LTZ and now own a 2014 Impala 2LTZ with the HID headlights.

The 2012 Impala had good headlight illumination - especially the hi-beams.

The HID headlights on the 2014 Impala are not as bright as I thought they would be and have a very distinct "cut off" for the range of the lights. At night, every little bump in the road (I live in the Midwest with terrible roads) causes the light "cut off" to bounce up and down. I am still not used to the new HID lights and do not feel they are much of an improvement over the 2012 model.
 

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Discussion Starter · #13 · (Edited)
I previously owned a 2012 Impala LTZ and now own a 2014 Impala 2LTZ with the HID headlights.

The 2012 Impala had good headlight illumination - especially the hi-beams.

The HID headlights on the 2014 Impala are not as bright as I thought they would be and have a very distinct "cut off" for the range of the lights. At night, every little bump in the road (I live in the Midwest with terrible roads) causes the light "cut off" to bounce up and down. I am still not used to the new HID lights and do not feel they are much of an improvement over the 2012 model.
Yes, I recently rented a 2014 Impala Limited (that is to say, the old model). The halogens on that were pretty strong as you say.

According to a post higher up, CR thought the HIDs on the 2014 were acceptable but weak compared to other applications. I had adaptive HIDs (self leveling, steer with the car) on my 2006 BMW 325i, which also had halogen fogs that were programmed to stay illuminated on either low or high beam. The cut-off on the HIDs' low beam is sharper, for sure, but the high beams on a country road would throw an arc of brilliant light down the road and at the surrounding scenery, and that arc would turn with the steering wheel. The thing to remember is that the high beams are the main beams and should be used whenever there is no opposing traffic or fog present. I see a lot of people driving on low beams when they are not following anyone and there is no opposing traffic.
 

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Discussion Starter · #14 · (Edited)
Update. After 31/2 years and nearly leaving the road last rainy Thanksgiving night (I just couldn't see the road) I traded the Impala for a Honda Accord, which has an excellent standard (halogen) lighting system. The Impala was a great car compromised by a major fault that GM did not see fit to address (see the other complaints online for the same model year and later). So much for the new GM.

https://www.carcomplaints.com/Chevrolet/Impala/2014/lights/exterior_lighting.shtml
 
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