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Interesting Link:
http://mb-soft.com/public/headlite.html


Gary C

Some people have gone so far as to remove the fuse in their hybrids to turn of daytime running lights. Every little bit helps, but I personaly would use it as a last resort.

Interesting post. Also interesting - the Corvette has had an iFCD since 1992?! Why the hell don't other cars have this technology in them if it is 15+ years old?!

I've always wondered about the actual visibility improvement of headlights on. I don't actually think there is that much, if any. If you want improved visibility get (or get your car painted) a lighter color or red. I think visually the easiest color to see is yellow. I think light green might be good as it has such a lot of yellow in it. But a silver or white (except in a fog)--when you have your lights on anyway-- is perfectly visible. The color shows up way way way before the lights do during the day. I have done an experiment (ableit not scientific) of when I see a car from the other lane and really a light car shows up first. Some colors like electric blue might work really well too.

I think this started back in the Kennedy administration, kind of gets me up there. And there was some increased interest in highway safety. But I really doubt this one. Sounds like it might have been to quiet the critics who wanted lower mph on the highway, which, imo, was still a good idea and one that REALLY decreased deaths.

--des

This one gets my dander up. I'm a big believer in visibility, and my family has driven with headlights on since the 1970s -- back in those days people would point at your car and yell "your headlights are on!" if you had them on during the day. Not because of fuel economy -- most people aren't aware of any connection -- but just because it was unusual, and most cars didn't have headlight alerts to remind you that you left them on when you got out. Nowadays here in the Pacific NW about half of all driver use their headlights during the day, even in the summer when it hardly ever rains.

I've stopped driving with lights on during the day since I started hypermiling, but it does bother me not to be doing it. I plan to replace my parking and tail lights -- specifically, those that aren't operated by turn signal blinkers -- with the brightest LEDs I can find so that I can once again have running lights during the day.

I believe there's a substantial safety benefit to having SOME kind of lights while your vehicle is in operation. In the busy urban environments where I do much of my driving, the streets are lined with parked cars. The more clearly that operating vehicles distinguish themselves from parked cars, the better. Don't forget that even on sunny summer days there are numerous situations where visibility is limited: shaded or filtered light environments, evening situations where drivers may be partly blinded by sunlight (and on our hills, this can happen starting 2 hrs before sunset), and parking garages. Even parking lights can do a lot to alert others that you're coming.

FWIW, even in the summer I also bike to work with automotive running lights blazing (2 pair of amber LEDs in front, 2 pair red in back). Only consumes 2W, or 4W when the kid trailer is also plugged in. I don't think there is a single person here who would tell me there's no benefit in that. Don't forget that motorcycle headlights automatically turn on when the engine is running. So why shouldn't cars do the same?

OK, back to this guy's assertion. I don't doubt that headlights cost a fraction of a mile per gallon, and I don't doubt that automotive alternators are inefficient, and I don't doubt that his 'Vette's pop-up headlights cause a lot of aero drag, but 2 extra hp disappearing into the alt when you kick the lights on?

No freakin' way. That puts it at 1/4 to 1/2 of the impact of turning on the A/C. If it were that much, you'd feel it big-time when you turn the lights on or off while you're driving at a steady speed. Afterall, turning the A/C on or off is HUGE, easily felt by the passengers as well as myself, at least on any car I've owned. Yet I've never felt a even a slight difference in any car I've owned when I turned the lights on or off.

Again, half a mpg -- maybe -- I'd believe. But any more than that seems like BS urban legend to me.

Somewhat interesting. The amount of numbers thrown in there are highly suggestive of a BBB (B--ls--t Baffles Brains) article.

What is conviniently left out is that the alternator will turn REGARDLESS of whether the lights are on or off. The alternator produces juice to charge the battery. If the juice is not needed, it's wasted. I'd rather use my headlights and make productive use of what the alternator produces rather than just waste it.

It might matter where you live re: headlights on, but I don't see it in a place that has 320 days of sun shine (or so they tell us :-)). On a sunny day, you can't really tell if the lights are on til you get right up to them, because the sun reflects part of the lamp whether the light is on or not. But if you have a lot of cloud cover maybe it would matter. I still say I can see the lighter colored cars first, whether or not the lights or on but again I speak from someone in a sunny state.

I would never yell at a driver for lights.
If you had scan gauge you could test out the mileage thing with real data, as to whether it hurts mpg. I would guess anything extra including a radio or CD player might effect it in minimal ways-- not necessarily detectible.


--des

I make it a point to drive with my lights on in my current environment. A lot of these roads are two lanes limited at 55mph (which means people are usually doing 60+) with passing zones that are used frequently. The last thing I want is to get hit head-on by someone who didn't see me and decided to pull out. You guys probably wouldn't hear from me for a while, if ever again depending on what hit me.

Somewhat interesting. The amount of numbers thrown in there are highly suggestive of a BBB (B--ls--t Baffles Brains) article.

What is conviniently left out is that the alternator will turn REGARDLESS of whether the lights are on or off. The alternator produces juice to charge the battery. If the juice is not needed, it's wasted. I'd rather use my headlights and make productive use of what the alternator produces rather than just waste it.

Sorry - not the case.
True that the alternator spins with the engine. However the mechanical load that the alternator presents to the engine varies with the amps that are being demanded of the alternator at the time.

In other words, if only the vehicle computer and pumps and injectors are running the alt is not being asked for much output. So it does not present much of a load to the engine.

If you turn on the cabin fan and the high beams and fog lights and stereo and... you get the idea, then the engine has to work a lot harder to turn the alternator - because it needs to produce all that electricity. So the hp that is "lost" to the alternator depends on how much electrical stuff is running.

... On a sunny day, you can't really tell if the lights are on til you get right up to them, because the sun reflects part of the lamp whether the light is on or not. But if you have a lot of cloud cover maybe it would matter.... --des

I read that the first major study on this was in Sweden where they have long dawn and dusk periods, with the sun never getting very high in the sky at any time of the year. They found statistically lower accident rates with headlights on and worked to promote daytime running lights.

I believe Canada was one of the next countries to promote daytime driving lights, again a country in relatively northern latitudes.

We here in the US have lots of sun, and the conditions are different from those where the first studies were done. So as usual, ymmv.

Back in my motorcycle days, they said using headlights during the day reduced the risk of a collision by 15%.

A few weeks ago, I set a personal best (80.3 mpg) when I went into work an hour later than usual and didn't have to use the headlights. I've close to 80 since, but never have exceeded it yet.

Overall the most efficient and safe system would be to have all cars with only an 'Auto' setting for the lights. They come on when it gets dark, tunnels tec.

I can definitely see it in such an environment. The lighting even during the day (perhaps not in the summer) might even be less bright.

NM, otoh, is quite bright most of the time (gosh this year has been strange), but putting lights to makes no sense. You can't really see lights anyway with the sun so bright.

It would be interesting to see if this was true or not in various environments and road conditions.

The two lane driving at high speeds is another thing I don't see here. Anything under 4 lanes is quite the exception.
But I'd do it if I thought it would be safer and not really worry about a miniscule amt. lost per gallon.

--des

I read that the first major study on this was in Sweden where they have long dawn and dusk periods, with the sun never getting very high in the sky at any time of the year. They found statistically lower accident rates with headlights on and worked to promote daytime running lights.

I believe Canada was one of the next countries to promote daytime driving lights, again a country in relatively northern latitudes.

We here in the US have lots of sun, and the conditions are different from those where the first studies were done. So as usual, ymmv.

I've been at the drag strip, just about all the cars have one tail light/ one head-fog light on going down the track. would be a neat idea to have on all cars- maybe make them bright magnified LED lights.

Interesting that we've got people from SW states saying headlights aren't noticeable in sunlight. Maybe the sun really is that much brighter there, but it's not like it's dim here. And it's dry and sunny all summer here too. I guess one big difference is tree cover. On almost all side streets and most arterials you're ducking in and out of shadows a lot of the time. If I don't take the freeway to work I probably spend 20% of my time in the shade even on the hottest, sunniest day. If I'm driving on the residential streets in my neighborhood (where IMO visibility is critical) it's more like 50%. You'd better believe headlights make you a lot more visible in that situation.

Also, even on open 2 lane rural highways, I'd sure rather that oncoming traffic know 1-2 miles out (or even further) that I'm coming. One thing I've learned from years of bicycling is that even if you are plainly visible to someone reasonably close to you, you are far safer if you are visible at a distance, giving other drivers have to prepare for their interaction with you. I've spent enough hours on desert highways to know that you see oncoming cars minutes earlier if they have headlights than if they don't, even when the sun is out. I consider that a safety benefit regardless of whether it's statically proven. ABS isn't statistically proven to be beneficial either, but I'm glad I have it.

I drive with my lights on as conditions warrant - although I happen to think my car looks killer with the headlights and fogs on.

I hate DRL's though. If I wanted my headlights to be on whenever the car's on, I'd turn them on. I would definitly do a DRL delete if I had DRL's.

Sorry, but not buying it.

But if you all are buying it.

I drive with DRL and "pahkin lites" until it's dahk. Then I drive with headlights and "pahkin lites."

For an EV, lights are a problem. Hybrid or ICE - noise. Inflate your tires 0.005 psi more.


-mr. bill

Interesting that we've got people from SW states saying headlights aren't noticeable in sunlight. Maybe the sun really is that much brighter there, but it's not like it's dim here. And it's dry and sunny all summer here too. I guess one big difference is tree cover. On almost all side streets and most arterials you're ducking in and out of shadows a lot of the time. If I don't take the freeway to work I probably spend 20% of my time in the shade even on the hottest, sunniest day. If I'm driving on the residential streets in my neighborhood (where IMO visibility is critical) it's more like 50%. You'd better believe headlights make you a lot more visible in that situation.

Also, even on open 2 lane rural highways, I'd sure rather that oncoming traffic know 1-2 miles out (or even further) that I'm coming. One thing I've learned from years of bicycling is that even if you are plainly visible to someone reasonably close to you, you are far safer if you are visible at a distance, giving other drivers have to prepare for their interaction with you. I've spent enough hours on desert highways to know that you see oncoming cars minutes earlier if they have headlights than if they don't, even when the sun is out. I consider that a safety benefit regardless of whether it's statically proven. ABS isn't statistically proven to be beneficial either, but I'm glad I have it.

A short statistical discussion of DRL's benefits is presented here: http://www.iihs.org/research/qanda/drl.html

I didn't read the cited papers, but the figure I've heard bandied about is an approximately 10% reduction in accidents that was observed in a taxicab fleet in the mid 80's. I'm sure they help people who are over-medicated see you. I don't recall any good studies that compared how good they are in sunny vs. cloudy conditions.

I remember a study of ABS that concluded that some skilled drivers (IIRC highway patrolmen) were statistically worse with ABS than without. As I recall the study thought ABS made the drivers over-confident and called for additional training on the proper use of ABS.

I encourage our 17 year old to drive our one car that has ABS, but personally mostly only drive ABS at work. I don't remember the last time it kicked in. If I don't have DRL's I try to remember to turn on the headlights on cloudy days or anytime there is snow cover when I am driving a white vehicle.

I'm surprised nobody has mentioned the fact that the author of the article is no fan of hybrids. Here's his final paragraph:

"A friend recently pointed out to me that the effect of the electrical load of the headlights is probably far greater (by percentage) for hybrid cars! He mentioned a fact that most people are probably unaware of, that when the A/C is running, hybrids cannot get over around 30 mpg! Since most people use their A/C most of the time, that pretty much defeats the whole purpose of a hybrid having the capability of having higher gas mileage. He said that a lot of people who buy hybrids soon sell them again when they discover the much lower mileage they were getting because they used their A/C. (I have separate and different gripes regarding hybrids, discussed in one of the pages linked below.)."

That caught my eye. So I went to his article about battery powered and hydrogen cars in which he slams hybrids. I'd encourage everyone to read it. http://mb-soft.com/public/cars00.html
To give you a quick idea, below is a short exerpt from that article. (BTW this gentleman refers to himself as "C Johnson, Physicist, Physics Degree from Univ of Chicago" I can't help but wonder what kind of grades he got)

"The advertising presentation of the popular Hybrid cars is rather misleading. Their performance is not what American drivers have come to expect from all the hype, and their consumption of electricity (and therefore increases in electric bills) comes as a great surprise to owners. Fortunately, they can still just buy gasoline, and drive an under-powered car, to avoid looking like having gotten "took!" Not even counting the fact that automotive batteries tend to only last a few years, so owners have THAT cost to look forward to as well."

For some reason he seems to think that all hybrids plug in, and has never heard of regenerative braking. There's an email address provided, so maybe someone can write to him and clue him in...

Low beams = about 0.15 horsepower (less for HID). I would use them on undivided highways, for the 'oncoming passers' reason mentioned earlier. In some states the law is lights on during rain. Is that the case in most states?

DAS

I'm surprised nobody has mentioned the fact that the author of the article is no fan of hybrids.
....
To give you a quick idea, below is a short exerpt from that article. (BTW this gentleman refers to himself as "C Johnson, Physicist, Physics Degree from Univ of Chicago" I can't help but wonder what kind of grades he got)

.....

For some reason he seems to think that all hybrids plug in, and has never heard of regenerative braking. There's an email address provided, so maybe someone can write to him and clue him in...

His website also has a lengthy essay about how the Twins paradox in relativity theory is "wrong". Call me a cynic, but I doubt that a guy who thinks he understands relativity better than Einstein did will be swayed by normal arguments.

File under "crank, internet website."

I might be the only one in a SW state posting and saying this. So it is just my mileage varying, I don't think we have anything like that many people posting. But I think there is a difference because we are talking about the *desert* SW. Not just say, CA or something.We don't have that many trees. So ducking in and out of shade is not so much of an issue.I don't think the sun really is brighter here, though to have all that open sky sometimes makes it feel that way. BTW, maybe this is nitpicking. I didn't mean to imply you can't *see* them, but that a lot of times you can't tell they are on til the car gets fairly close as there is all this light bouncing off them, on or off. I really notice the color car first. But maybe that is just me.

I don't drive a lot on the kind of 2 lane rural highways you mention. Once in a very great while maybe, but I live in the city.


BTW, I think we could disregard the author of that study if he is using the twin thought experiment to prove his points!!

--des

Interesting that we've got people from SW states saying headlights aren't noticeable in sunlight. Maybe the sun really is that much brighter there, but it's not like it's dim here. And it's dry and sunny all summer here too. I guess one big difference is tree cover. On almost all side streets and most arterials you're ducking in and out of shadows a lot of the time. If I don't take the freeway to work I probably spend 20% of my time in the shade even on the hottest, sunniest day. If I'm driving on the residential streets in my neighborhood (where IMO visibility is critical) it's more like 50%. You'd better believe headlights make you a lot more visible in that situation.

Also, even on open 2 lane rural highways, I'd sure rather that oncoming traffic know 1-2 miles out (or even further) that I'm coming. One thing I've learned from years of bicycling is that even if you are plainly visible to someone reasonably close to you, you are far safer if you are visible at a distance, giving other drivers have to prepare for their interaction with you. I've spent enough hours on desert highways to know that you see oncoming cars minutes earlier if they have headlights than if they don't, even when the sun is out. I consider that a safety benefit regardless of whether it's statically proven. ABS isn't statistically proven to be beneficial either, but I'm glad I have it.

Put your lights ON!!!!
http://www.youtube.com/watch?v=q5a0OAtzrXE&mode=related&search=

And be smooth about it.
http://www.youtube.com/watch?v=gpX97eg-W-k&mode=related&search=

What Happen? Where the hell did I die. It must have been a dream. OOOO cleanmpg.....LMAO

Hi All:

___In the article entitled “Ford Escape Hybrid Fuel Economy Experience and Ford HEV Employees Passion (http://www.cleanmpg.com/forums/articles/t-ford-escape-hybrid-fuel-economy-experience-and-ford-hev-employees-passion-125.html)”, the engineer presenting had an interesting and to the point slide that fits this thread nicely. The following was measured from an 05 FEH if that helps … The smaller the ICE, the more FE hit there will be with lights on.

4. Accessory FE hit includes the Radio at .1 MPG, Rear Defrost at .8
MPG, Headlights at .9 MPG and Fan on High at 1.3 MPG.

___I am pretty sure these numbers were referenced from the FTP75 and HWFET (EPA City/Highway tests) in place for the 07 and prior year vehicles. I should have asked :(

___Good Luck

___Wayne

One flaw in the article:

If a LARGE car or SUV is constantly traveling at 70 mph on Interstate Highways, yes, I see potential safety value in having the headlights on during the daytime, without seriously affecting fuel mileage. But for smaller vehicles, and those traveling at speeds below around 50 mph, there is certainly a considerable added cost for additional gasoline used!

The cost of energy consumed from the headlights is the power consumption of the headlights multiplied by the time they are used, multiplied by the unit cost of gasoline and divided by the ICE/alternator system's efficiency of energy conversion from gasoline to electricity.

None of these variables has much to do with whether you drive a car or SUV. There may be a slight difference in energy conversion efficiency between the two, but probably not enough that you'd notice a difference at the pump. The main reason that you notice the difference in a small car's MPG is that the energy consumed represents a much larger fraction of the fuel consumed, because less fuel is consumed per unit of time in a smaller car than an SUV. The fuel consumption in l/100km for a constant speed between the two should be roughly the same, as would the cost of additional gasoline used.

He is correct that the headlights will consume more energy at 50 MPH than at 70 MPH, simply because they're on 7/5 as much time, or 40% longer. This means that they alone will consume 40% more fuel. However, as we all know, the aerodynamic differences in energy consumption far overwhelm the increase in energy consumption from the headlights, so you still come out way ahead at 50 MPH in the dark.

A better way to figure out estimate how much fuel is being used by the DRLs in any car would be to take the FEH's estimate and convert it to volume of gas per unit time (e.g. tsp/hr); this would be more consistent from car to car. This would require knowledge of the test conditions used to get the .9 MPG estimate, specifically the average speed and average fuel economy of the test.

I had not been aware that the ventilation fan power consumption exceeded that of the headlamps; I'll need to keep this in mind in the future and keep my fan speed only as high as necessary to accomplish the needed task. I sometimes use the heater (mainly on slow, steep uphill grades) to circumvent use of the radiator fans, whose power draw can be fairly substantial.

Well, this has certainly got me wondering. Obviously some energy is used in running the lights. I will do some controlled experiments on the road and see if I can detect a change. Again, I can't physically feel a difference (unlike with A/C) but it may still be detectable.

Although I can't directly measure the MPG impact without road testing, with the ScanGauge's voltage display (while the engine is off) I am able tell that turning the headlights is roughly comparable to turning the fan on HIGH (something I've already learned to avoid while FASing). But both of these combined use less juice than simply having the key in the RUN position. Simply running the ignition, engine computer, sensors and whatever other electrical stuff sucks down more power than accessories do.

Haven't tested the damage done by my "80W" (claimed) stereo. Which would be the best test song? Led Zeppelin's "Dazed and Confused"? Dread Zeppelin's "Immigrant Song"? Or Lez Zeppelin's take on "Rock and Roll"? Who rocks harder, the original or the killer tribute bands? Only the ScanGauge knows for sure.

Immigrant Song. Definitely.

I'm surprised nobody has mentioned the fact that the author of the article is no fan of hybrids. Here's his final paragraph:


He mentioned a fact that most people are probably unaware of, that when the A/C is running, hybrids cannot get over around 30 mpg! Since most people use their A/C most of the time, that pretty much defeats the whole purpose of a hybrid having the capability of having higher gas mileage. He said that a lot of people who buy hybrids soon sell them again when they discover the much lower mileage they were getting because they used their A/C.


For some reason he seems to think that all hybrids plug in, and has never heard of regenerative braking. There's an email address provided, so maybe someone can write to him and clue him in...

ROFLMAO...........i've gotten over 50 on the highway going 60. maybe he needs to actually get CLOSE to one before he makes such ignorant blanket statements.

i'm thinking i need to make a visit to his site :)
;)

Overall the most efficient and safe system would be to have all cars with only an 'Auto' setting for the lights. They come on when it gets dark, tunnels tec.

i really think this would be good. i frequently drive home at dusk, and i am surprised how many drivers don't feel the need to have their lights on, though the state requirement is 1/2 hour before sunset. a mid colored car, say grey or black, doesn't show up very quickly when it's about the same color as the pavement.

He said you can't get over 30mpg in a hybrid with the a/c on........I think there may be something very wrong with my prius..........I just checked and I'm still getting just under 60mpg with my a/c on 78degree auto setting and my lights on low beam.....should I take it in to make sure something is not broken?

Immigrant Song. Definitely.You're right. This is pretty hard to beat: http://www.youtube.com/watch?v=3CO7FPU7a2g

But these chicks know how to do Zeppelin up right too: http://www.youtube.com/watch?v=_J2wDZ8HXzg.

Then again, the bar was set pretty high to begin with: http://www.youtube.com/watch?v=5ssI83i_ApI&NR=1

I've always wondered about the actual visibility improvement of headlights on. I don't actually think there is that much, if any. If you want improved visibility get (or get your car painted) a lighter color or red. I think visually the easiest color to see is yellow. I think light green might be good as it has such a lot of yellow in it. But a silver or white (except in a fog)--when you have your lights on anyway-- is perfectly visible. The color shows up way way way before the lights do during the day. I have done an experiment (ableit not scientific) of when I see a car from the other lane and really a light car shows up first. Some colors like electric blue might work really well too.

I think this started back in the Kennedy administration, kind of gets me up there. And there was some increased interest in highway safety. But I really doubt this one. Sounds like it might have been to quiet the critics who wanted lower mph on the highway, which, imo, was still a good idea and one that REALLY decreased deaths.

--des


YELLOW trucking company did just that. Here is a more complete explanation from the yellow racing site:

In the 1930s, A.J. Harrell, President of Yellow Transit Company, realized that the streets were becoming crowded with vehicles. Concerned for the safety of his drivers and passing motorists, he ordered that the entire fleet be repainted. Harrell said, "We need to find the safest color on the road."

Harrell collaborated with the fine folks at DuPont to develop the safest, most visible color. A color that belonged to only Yellow. They experimented. They tested hundreds of colors. They worked day and night. Until one day, they created the perfect color. It was unequaled in its vividness and its ability to be seen at great distances. They named it after a wild berry that grew in the South, "Swamp Holly Orange."

Mr. Harrell was thrilled. The employees were surprised. The customers were confused.

Although I will not repaint my vehicle, I would not disable drl or avoid using head/parking lights when necessary.

Safety first.... gas Savings not first.

He said you can't get over 30mpg in a hybrid with the a/c on........I think there may be something very wrong with my prius..........I just checked and I'm still getting just under 60mpg with my a/c on 78degree auto setting and my lights on low beam.....should I take it in to make sure something is not broken?

Uh, oh. I think mine's broken too! :eek:

In the 1930s, A.J. Harrell, President of Yellow Transit Company, realized that the streets were becoming crowded with vehicles. Concerned for the safety of his drivers and passing motorists, he ordered that the entire fleet be repainted. Harrell said, "We need to find the safest color on the road."......one day, they created the perfect color. It was unequaled in its vividness and its ability to be seen at great distances. They named it after a wild berry that grew in the South, "Swamp Holly Orange."


Ah HA!! I always wondered why all those orange trucks had the word Yellow on the side of them. I just thought the owner was color blind and nobody had the heart to tell him his trucks weren't really yellow.

:Banane06:

Hi SpartyBrutus:

___Thank you for the history lesson! I see the Yellow guys on the road every day and you are right, there trucks can be spotted a mile away due to that orange color! To bad most are traveling 10 – 12 over however :(

___Good Luck

___Wayne

You know I'd like one of those Yellow H2s because Priuses don't come in yellow! ;-P

--des

You know I'd like one of those Yellow H2s because Priuses don't come in yellow! ;-P

--des

No Hummer for me........but the wife and I are already talking about corvette millinium yellow for our prius when it gets enough scratches and such:Banane09:

The Mileage impact IMO is not worth discussing, the safety is probably improved, however IMO the light should not be so **** bright as to be an irritant, which some are. Personally I never allow them to remain on any vehicle i have owned as I just don't like them.:flag: