Unless you have a 10+ year-old car of the type that causes you to cheer when it actually starts in the morning. Then you don't want to risk it at every red light. ;)

Ah, but think of all the money you'd save if you traded that in for something more reliable!

30 per gallon or per tank?

Just wondering. Wouldn't that cause extra wear on starter and flywheel? Driving the speed limit will save a lot more gas, instead of 10 miles over like we do here in Georgia.

When I tried it the first time, I was amazed to see that I had gotten nearly 30 more miles on that tank than usual.

Answered it myself by reading :p

The original article claimed 30 more miles on a tank of gas on a car that apparently averages around 30 mpg (since the writer equated 30 miles with an extra gallon of gas).
I would also recommend that one pay attention to light timing to make sure one can have the engine started slightly before the light turns back to green if one is at a stoplight. If you delay traffic and make lots of people miss the next light (assuming they're timed well), then it's quite counterproductive since the best thing for a car's mileage is to not have to slow down.
Also of note is that BMW is in the process of introducing a system that automatically stops the engine when it is not in use, much like most hybrids, but on regular cars (starting with the 1series and 7 series I believe). This will become a common feature in the next few years on many brands of cars.

That's 30 more miles per tank, not per gallon. Headline is wrong. Had me all giddy for a second.

That's thirty more miles per TANK, not per gallon.

Read the article carefully. I still might think about shutting off the engine in some situations, but I'm not going to do it at every red light just to save that small amount.

If you have a fifteen gallon tank and get 25mpg, then you'll get 27mpg this way. Up to you.

If someone tried to do this in front of me at a redlight, they'd have a much bigger problem than trying to save gas.

"Unless you have a 10+ year-old car of the type that causes you to cheer when it actually starts in the morning. Then you don't want to risk it at every red light. ;)"

My car is only 6 years old and I cheer when it actually starts! (It's a Ford. 86k miles and already on it's second engine.)

Personally I'd rather use a little more gas, and save the wear & tear on my car (and not piss off the jerk behind me at the red light). The only time I shut it off instead of idling is if I'm going to be stopped for a few minutes (for example at railroad crossings).

My car is 20 yrs old and solid as a tank. It is not fuel injection. I let it idle in the winter while I shop as its normally butt ass cold. However, I think with new cars, this idea could work. But like shekondar says, I am not crazy about the wear and tear on my starter. Starters are a pain to replace.

Destroy your engine to save 2 dollars. Great.

Starting your car is horrible for it. Sounds like it could be more costly in the long run.

If someone tried to do this in front of me at a redlight, they'd have a much bigger problem than trying to save gas.

Would they really? What problem might that be?

Y@permissionmag: I think you may be right on this one.

As near as I can tell the source of the "Idling saves fuel" fact comes from Natural Resources Canada (Office of Energy and Efficiency?) Anywho they give no public stats online as to how much petrol turning off your car after 10 seconds actually saves, just that turning it off after 10 seconds is the point when at which it takes less fuel for your car to start up versus leaving your car running.

So how much mpg would you save?

It would be irresponsible to say. Why? Because when your car is idling you're getting 0.0 miles per gallon. Since you're not moving anywhere you're just eating fuel while you're idling and I think that's the overall point that Natural Resources Canada is trying to make.

Someone needs to get Myth Busters involved in this - I'm with most on here who say that more harm will come to the motor and all the accessories attached to it, such as the starter, from practicing these methods.

I am also going to have to agree this is not the best idea. Although yes, you will save gas, starting a car is not good for the engine. It is mildly rough on the starter, rough on the battery, hard on the transmission, and very rough on the engine due to the time it takes to build oil pressure critical to protecting the engine.

I have always thought the best way to save gas is to keep the car well tuned by following your maintenance schedule, and changing driving habits. Driving habits being the big one here. . . stop hot-rodding!

Couldn't you just throw the car into neutral and achieve most of the same effect without starting your car at every red light?

My car already does this! (toyota prius) its one of the many things it does to maintain fuel efficiency. In my case, the engine doesn't actually spin again until about 8mph, and the electric motor covers any delay there would be in responsiveness.

Of course theres one situation that this doesn't account for... winter! even the prius refuses to shut off the engine at a light if I have the heat switched on. I guess if you are sweedish, you just have to pack an extra scarf when driving?

Other neat prius fact: it stores 3L of "coolant" in a thermos style container in the engine. a minute after the car is powered off, it pumps the warm fluid into the container. On start, it re-injects it to pre-warm the engine. this gives the fuel benefits of a warm-start, even the next day! every little bit helps

@Musician78: Absolutely correct! The one of the most damaging things you can do to your engine is start it cold. Starting it warm with no oil pressure isn't much better. You cause additional wear on your starter flywheel gear teeth, battery, alternator, and en engine internals not to mention if you did this in stop and go traffic you could potentially overheat your car and yourself in the summer.

This is one tip thats definitely NOT worth it.

instead of spending time and wasting effort on affixing band-aids to the problem, why not focus on the truth:
the GAS engine is outmoded. When we start to try and piece together measly savings by turning the car off at stop lights, don't you think we have hit a wall?

Starting your car from cold is damaging, but if it is already warm it isn't and it will also start easier. Just wait until it's warm.

Arrgh, it's just a Canadian-backed study to substantiate a no-idle ordinance one Toronto community enacted.

I remember reading about this last summer while working in Ontario

Another thing to consider, it might be illegal, depending on where you are, to turn off your car in the middle of traffic.
If your car is new, works well, and is warmed up, this probably isn't very bad for your car. I'd say if it seems to start instantaneously once warmed up, it's fairly safe to do this. If you car springs back to life a little slower, that might be a little more unpleasantness than your engine needs too deal with.
If I weren't so lazy, I'd ask my old man, he's been a powertrain engineer for 30-some years. He's driven cars that do the engine shut off automatically when the brakes is applied and the car is stopped, and they have some other things in them tweaked to make starting so fast that he couldn't get his foot off the brake and on the gas before the engine restarted.

"The Swiss like this method and it's the law in several of their cities to turn off your car at stoplights."

It's amazing that people are OK with a LAW that says you have to do this. Move along sheeple.

Saving a couple of gallons per tank may not be the most exciting thing, but I like the idea at long lights to just prevent my car from spewing all that crap in the air. A couple of lights near me take forever - I think I'm going to try it (and hope I'm not in front of bambino!

This is at least the second thing I've seen referenced here (the other being changing your boarding pass) that I think it incredibly misdirected.

I tried this last fall for about two days. It ended badly, with me not being able to start my car at a busy intersection, in the left turn lane, during rush hour, in the cold rain, in northern Virginia. I was wet, frustrated, embarrassed, and had a lot of angry drivers behind me.

As it turns out my four year old car had just about run through its original battery. The time between stop lights wasn't enough for the alternator to put any charge into the battery. I drained it and then couldn't start the car again. Luckily for me there was a car dealership at the corner that loaned me one of those portable quick-jump-start battery units. I still ended up blocking traffic for about a half an hour.

I wouldn't recommend this to anyone. Is the wear on your battery, starter, flywheel and other components, and the risk of being stranded really worth an extra 1-2 gallons of gas saved for every 250-300 miles driven?

Would Donna in the red camaro please ask Car Talk for us? (Can anyone imagine doing this repeatedly in a city like Boston or NY? I think the courts would rule justifiable road rage for whatever the result might be)

@shekondar:

It's a Ford what?

This seems silly.

Although, I wish there were more drive-thru lanes that were on a downward slope. There were a couple in the Bay Area, that presumably, some virtuous person planned. Sweet sweet goodness, being able to coast your way through the line, engine off, until you could grab your vittles and run. No breathing fumes, either.

Trai_dep: that is the coolest thing I've seen in this thread. That's a great idea.

@tcabeen: Thats the first thing I thought when I read this. My family celebrates when the car starts in the morning... there is NO WAY IN HELL I would ever do this at a red light...

Coasting... reminds me of this article of a guy taking it way too far......

http://www.motherjones.com/news/feature/2007/01/king_of_th...

30 more miles per gallon, he says? No way. He must be smoking too much of whatever is coming out of that tailpipe in your photo.

Wow. Every "gas saving" tip I've read lately has been incredibly stupid. As everyone else has indicated, all the wear and tear you incur just isn't worth the extra 1 or 2 gallons you're going to supposedly save. If you want to save gas, drive less.

@trai_dep: wow what a great idea! I do agree, I like the coasting thing.

@pe_tor: It is definitely *not* illegal anywhere to turn your motor off while at a stoplight. Not starting it back up again and sitting there? That could conceivably result in a fine, but even that's unlikely.

The Germans do this in many places and even have countdown timers on many longer stoplights so that you know when you should turn your car off (along with a sign reminding you to do so). Germans are fricking obsessed with taking good care of their cars (even the non-high end ones, they don't all drive Mercedes or Beamers), so I find it highly unlikely that turning your engine off at a light and then re-starting it (assuming it's warm) is damaging. If it was, they really really wouldn't do it...

Seriously, don't get between a German and his car-- right now there is some hardcore backlash against some lawmakers there who suggested putting a speedlimit on the autobahn to be more environmentally responsible.

Hmmm....interesting. I've always been told that unless you were going to be in idle for a long period of time (over 10min)..It's best just to keep your car running. I was under the impression that starting your car eats up more gas than idling for a few minutes...

Now obviously I don't know jack about cars...After looking over the comments here it looks like shutting down your car does save gas, it just isn't good for it?

Just a thought, wouldn't doing this often, even if your car has fuel injector, starting up the car would wear out the starter sooner. I mean yes we start up our car every single day but imagine if your starter fails right when the light turns green.

I think as another commenter mentioned this topic is good fodder for the Mythbusters. So many "tips" or common practices for cars harken back to the days before you had fuel-injected engines and other modernizations. Could it wear out your starter faster? Possible, but we don't know. Just saying it's "bad for the engine" is a non-starter (ha!)-- no one has the research to back it up.

@grouse: Multiple expletives flying from multiple drivers having to pull into oncoming traffic trying to get around their retarded ass because they wanted to save a few pennies. Maybe even a flying smoothie.

My vehicle is not fuel injected, so I won't be doing this. Then again, it gets 63/mpg.

Right. Let's do some math here.

Let's assume you own your car over 100,000mi.
Let's also assume you get 20mpg.

100000mi/20mpg = 5000gal of gas over the life of the car.

Now, let's assume a 15gal gas tank. Seems average.

5000gal/15gal.per.tank = 333.33tanks.

At 20mpg, your 30mi extra of is 1.5gal/fillup.
Let's also assume gas is $2.75/gal.

333.33tanks * 1.5gal/tank = 500gal.
500gal*2.75/gal = $1375.

So, you theoretically save $1375 doing this. That's a pretty big chunk of change, but it assumes that this will do no additional damage to your engine. Knowning what I know about engines and oiling systems, unless you install a preoiler, you're going to do more damage to the valvetrain and the bearings doing this. How much is really dependant on too many things to call safely, but I think we can assume that a large percentage of engines might have to be rebuilt or replaced doing this when they maybe wouldn't have had to be. Also, you'll definitely go through at least twice as many starters and batteries this way and those are neither cheap nor easy to replace in many cases. Thus, I call it a gamble. I'll leave it up to you, but I for one am leaving my engine running.

Sounds like too much stress and strain on the car to be worth it in the end.

I'll never forget what I saw while on a business trip to Barcellona.

When a cab picked-up a passenger in the taxi line at my hotel (Ritz-Carlton), the drivers did not start their engines and pull-forward a spot; they simply PUSHED their cars ahead!

I cannot imagine any US cabbie doing that....

Jamie & Adam? Are you listening? This would be a good one.

I do turn off my gas-guzzler when I stop but only when I'm waiting for a train. They average 5-10 minutes here. I've considered knocking on windows to tell others about this idea but figured I might get "a flying smoothie" as bambino mentioned.

@grouse:

Probably a severe beating. Some hospital bills, perhaps a smashed out window. Maybe worse. It happens. And you never know, he could be the dude that commits acts like that.

Although sometimes I feel that road rage should be allowed in extreme cases. Like when some asshole doesn't want to do the speed limit, and doesn't want to pull over for the line of cars behind him that wants to do the speed limit.

Or people who do not merge as they pull onto the highway. They just get on and don't even look.

Or people who tailgate the crap out of you when you can't help going to slow because the asshole in front of you is preventing any increase in your speed. You are therefore forced to tailgate him in hopes of him pulling over.

Actually, come to think of it, I can think of lots of reasons to legalize road rage...

Stopping your car at stop lights, at least with standard cars seems to be a really stupid idea (from comments)

However, if you're like me, stopping it while you're stuck in a drive-through for 5 minutes is a good idea.

Although I must say, the idea of adding countdowns to traffic lights would be a very wise decision. It makes the red-light runners a little less common (since there's no "guess" to if you can make it or not) and such, and you can tell if you're going to hit a red light earlier.

Sounds like a good idea, but it's apparent from the number of people still without fuel-injection cars that idea is better in theory than practice. Actually, it sounds sort of gimmicky (and this coming from someone who used to try to reduce brakewear by slowly drifting his 1985 Buick LeSabre before every stoplight), and I think what will happen first is improved technology that provides some sort of automatic shut-off when idling--similar to what pe_tor said above. The clear advantage here is that drivers wouldn't have to think about it, like a refrigerator light going off when you shut the door (silly analogy, I know).