Driving Ecologically [Update]

Since mid-summer, I’ve been the proud owner of a Peugeot 306 (as seen here). It was a used car (1994) and an affordable buy. Like all older cars, the fuel economy is not up to par with recent cars, but it’s not terrible either.

Since I only got my drivers license some three months prior to getting the car, I’ve been trying to learn to drive ecologically / economically. I do not drive much, I only use the car for longer trips (parents, weekend getaways, IKEA). In the process I have picked up a few tricks which I’d like to bounce off of you, esteemed reader and/or more experienced driver than me.

  • Drive in high gears
  • Switch to 4th a little earlier than you normally would.

  • Sometimes, skip a gear
  • Switch from 2nd to 4th, or in better cars than mine, from 1st to 3rd. But be careful and skip to a gear that makes sense for specific type of situation.

  • Freewheel whenever you can
    If you see a red light ahead, if you’re going downhill, if you’re stuck in traffic, freewheel as much as possible.

    Don’t freewheel, I’m told it’s a bad idea for both safety reasons and fuel economy reasons.

  • When driving on the highway/autobahn/motorway, remember that your most efficient speed is often below the speed limit (I believe the average value for most efficient speed is 55MPH in the highest gear). (Thanks Jonathan)
  • Don’t carry superfluous weight. (Thanks Jonathan)
  • Don’t use an unloaded roof-rack or anything else that will introduce unnecessary drag. (Thanks Jonathan)
  • If your car has air-conditioning, only use it when you absolutely must. (Thanks Jonathan)
  • Learn the road and the stoplights

Know when to accelerate and know when not to, so you don’t have to break / accelerate all the time.

What did I miss? Which of these would annoy you, were you driving behind me? Which of these would be dangerous?

[Update]: See comments for more tips / corrections. Special thanks to Jan and Jonathan.

13 thoughts on “Driving Ecologically [Update]”

  1. J?n Varhol says:

    Freewheel isn’t good in “modern cars” like your Peugeot (I’m still driving Lada – it’s Russian car).

    If you got really old car (Lada etc.) fuel injecting is not controlled by electronics. It depends on how much pressure is on the pedal. So if you freewheel on that types of cars it really IS saving you fuel.

    Newer one (as yours) has electronics controlled injecting, and if you aren’t pressing the pedal, then delivery of the fuel is decreased or stopped. So you won’t need to freewheel. BUT, if you do, there is more consumption on fuel.

    Yes, that sounds crazy, but ask any motor mechanic.

    Next: skipping some gears can damage gearbox. If you want to save fuel in this way. Count your savings if it is bigger than cost of brand new gearbox.

    Next: if you go on 3rd gear with pedal half pressed at immovable speed, you spend less fuel, than on 4th trying to speed up a litlle pressing predal.

    It is only my opinion based on prax and others thoughts.

  2. Joen says:

    Newer one (as yours) has electronics controlled injecting, and if you aren?t pressing the pedal, then delivery of the fuel is decreased or stopped. So you won?t need to freewheel. BUT, if you do, there is more consumption on fuel.

    I ask because I want to learn. I know the fuel injection is decreased, but unless I actually freewheel (car not being in any gear), the motor brake automatically decreases the speed of the car. So, unless I’m mistaken here which is entirely possible, would you not save more fuel by freewheeling? If I’m wrong then I’d better update this post!

    Next: skipping some gears can damage gearbox. If you want to save fuel in this way. Count your savings if it is bigger than cost of brand new gearbox.

    Of course, one shouldn’t drive in a too high gear, isn’t that what could harm the gearbox? Or is it simply the act of skipping a gear?

    Next: if you go on 3rd gear with pedal half pressed at immovable speed, you spend less fuel, than on 4th trying to speed up a litlle pressing predal.

    I’ll add that, thanks.

  3. J?n Varhol says:

    Yes, freewheeling get the motor brake working, but what is important, while you are useing motor brake, deluvery of fuel is closed. It is closed far more than when fou freewheeling. Thats true.

    All this is true only if you are not pressing pedal while motor brake at all.

  4. Joen,

    I would avoid freewheeling completely. Not for fuel economy purposes either. When you are freewheeling the vehicle is much more difficult to control, you should have drive to the wheels at all times. This is the only way to be safe (I presume your personal mortality is more important to you than saving a few bucks on fuel).

    You should get in as high a gear as you can, as early as you can. But make sure that the gear you choose is suitable for any gradient you are driving on. If your gearing is too high for an uphill climb then your engine will struggle and you will use more fuel. If your gearing is too high for a gradient descent then you will find you have to brake more frequently and more heavily – else the car will run-away with you (in a low gear the engine is a very effective brake).

    When driving on the highway/autobahn/motorway, remember that your most efficient speed is often below the speed limit (I believe the average value for most efficient speed is 55MPH in the highest gear).

    Don’t carry superfluous weight.

    Don’t use an unloaded roof-rack or anything else that will introduce unnecessary drag.

    But perhaps the most important thing to learn is “read the road”. Look as far ahead as you can, watch other traffic and pedestrians – learn to anticipate the actions of other road users. Keep reasonable spacing between yourself and the vehicle in front. Then you will be able to maintain a steady rate of progress with fewer throttle changes – this will have a considerable impact on your fuel consumption.

    Kindest regards,

    Jonathan.

  5. Joen says:

    This is great advice. Permit me to update the article.

  6. One more thing – if your car has air-conditioning, only use it when you absolutely must. Air conditioning uses a lot of fuel. It’s better to open the sunroof and wind down the windows (although opening the sunroof and/or windows will increase the drag and thus fuel consumption, it is still more efficient than air-con).

  7. Joen says:

    Ah, good AC point Jonathan.

    There’s no AC in my car, but there is a ventilator.

  8. Dylan says:

    Unfortunately most of these wouldn’t apply to those crazies with automatic transmission.

    As for the AC versus windows down, I believe the Mythbusters did an experiment on it, although I can’t quite remember their results… I do remember something about their results being inconclusive or flawed or something though.

  9. Jonas Rabbe says:

    I suddenly noticed how much I use your blog for updates on your life. I didn’t even know you got a car.

    Just wanted to comment on two points.

    1. Freewheeling. I assume you, by freewheeling, mean not pressing the accellerator and not having the transmission in gear. This is bad since the engine will be idling and using more fuel than you think. If you keep the transmission in gear, the car doesn’t need to inject fuel to keep the engine from stalling. Also, you get the braking effect which is very necessary on some steep stretches around the world.

    To inject an anecdote at this point. My family and I were in California and driving down to the valley, at one of the rest stops along the way down there was a Mustang with its brakes on fire. There was a person who had never heard of motor braking. Even automatic transmissions have the possibility of downshifting.

    2. Aircondition. The mythbusters actually found that the difference between running with the windows open, and running the AC was neglible. While the Mythbusters aren’t always the most scientific the results are probably quite close. This is pretty vital, since the AC does increase fuel consumption noticably.

    This means that if you are trying to choose between running the AC or opening the window, it will probably be better to turn on AC, especially if it is very hot. Opening the window will not cool the air which could mean you get hotter and then an unsafer driver. There is a direct link between your body temperature and agression and how you react to situations.

  10. Joen says:

    I suddenly noticed how much I use your blog for updates on your life. I didn?t even know you got a car.

    Actually, I didn’t use my blog for life updates. That’s actually something I’d like to change, for reasons unrelated to this (good writing, I’m told, is news with a a) a personal angle, b) an angle for society and c) related somehow to the point of the medium, in this case treehugging blog 🙂 ).

    Freewheeling. I assume you, by freewheeling, mean not pressing the accellerator and not having the transmission in gear.

    Correct, that’s exactly what I mean.

    This is bad since the engine will be idling and using more fuel than you think. If you keep the transmission in gear, the car doesn?t need to inject fuel to keep the engine from stalling.

    Hmm… I’m glad I labelled this entry “voxpop”, because I’m seriously getting schooled. Long story short: I trust you’re right. I’ll stop freewheeling 🙂

    My family and I were in California and driving down to the valley, at one of the rest stops along the way down there was a Mustang with its brakes on fire.

    On FIRE? as in fire fire? Wow crazy! My cousin (who was instrumental in helping me find this car, by the way) told me that if I had to brake really hard for some reason, it might help “cool down the brakes” by letting go of the pedal afterwards (if possible).

    The mythbusters actually found that the difference between running with the windows open, and running the AC was neglible.

    Even so, using the ventilator, or not using either the ventilator or the windows at all must be better on fuel consumption than AC, right?

    There is a direct link between your body temperature and agression and how you react to situations.

    I can imagine. But somehow this feels less of a problem in cold Denmark…

  11. Somewhat related…

    I was recently surprised to learn that so-called “green” cars like the Toyota Prius may not in fact be as ecologically friendly as we have been encouraged to believe.

    A recent report by the US-based CNW Marketing Research has analysed the environmental impact of a wide range of vehicles from a “dust-to-dust” perspective (ie: from a vehicle’s creation to its ultimate destruction) and the unbelievable winner turns out to be the Jeep Wrangler.

    It’s probably worth remembering that the manufacturing of a car is often more environmentally damaging than the running of it. In which case, I congratulate you Joen for buying a used vehicle rather than a new one!

    Reference: Jeep Wrangler: Is this the greenest car on sale?

  12. Jonas Rabbe says:

    On FIRE? as in fire fire? Wow crazy! My cousin (who was instrumental in helping me find this car, by the way) told me that if I had to brake really hard for some reason, it might help ?cool down the brakes? by letting go of the pedal afterwards (if possible).

    Yes, on fire as in smoke and flames. Looked quite dramatic. It is the coating on the brakes (disks or pads, forget) that can overheat and ignite if they don’t get a chance to cool down.

    Even so, using the ventilator, or not using either the ventilator or the windows at all must be better on fuel consumption than AC, right?

    Correct, using the ventilator or not running anything for “climate control” is always more fuel efficient than AC. I was only talking about open windows vs. AC. Running the ventilator (if that is enough) will be better than driving with an open window. If the ventilator is not enough to cool you and you don’t have AC, I would suggest you crack the windows as it is better to be cooled down than get overheated. This is what we did in 2001 when the AC in my mom’s car was broken and the temperatures in southern France topped 50 degrees C.

  13. Joen says:

    A recent report by the US-based CNW Marketing Research has analysed the environmental impact of a wide range of vehicles from a ?dust-to-dust? perspective (ie: from a vehicle?s creation to its ultimate destruction) and the unbelievable winner turns out to be the Jeep Wrangler.

    It?s probably worth remembering that the manufacturing of a car is often more environmentally damaging than the running of it. In which case, I congratulate you Joen for buying a used vehicle rather than a new one!

    Reference: Jeep Wrangler: Is this the greenest car on sale?

    Whaaa? Color me completely surprised. If that’s even half accurate I have some things to rethink.

    But thanks, yes I’m very happy about my used Peugeot. For what I paid for it, it really doesn’t feel “used”. I must admit though, that more than ecological thoughts, it was economical thoughts that drove me towards a used car: a simple calculation revelaed that with the distances I’ll drive over then next 10 years (hopefully less than 15000 km a year), it wouldn’t make any economic sense with a new car.

    This is what we did in 2001 when the AC in my mom?s car was broken and the temperatures in southern France topped 50 degrees C.

    I won’t argue that that’s hot.

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