Speeding costs more than it’s worth

The warm weather and long days are here, which brings open windows, loud music and long drives to beaches, ball games, concerts or adventurous road trips. Whatever the reason, this time of the year has people driving longer and further on our roads. Too bad gas prices are high, and continue to climb!

An easy way to save at the pump is to visit it less. That doesn’t necessarily mean that you have to use your car less; it just means that you should think about using it differently – don’t speed. You’ll be happy with the savings. It’s that simple.

The fast lane on the highway usually moves around 115-120 kph, even though the speed limit is 100 kph. It’s always tempting to hop into that lane and cruise at a faster speed to reach your destination sooner. But, how much sooner are you really getting there? Why rush there when you can leave a few minutes earlier for the same effect? I know, I know – easier said than done.

But let’s break this down. Say your daily commute is 20km of highway driving. At 120 kph, that takes you 10 minutes. Now, if you dropped your speed down to 100 kph, that commute would now take you… drum roll please… 12 minutes; only 2 minutes longer!

Now, the next time you’re driving on the highway, take a look at your tachometer and notice your engine revving when you’re driving at 100 kph – probably around 2500 rpm for most. However, at 120 kph, your engine is spinning at 3000 rpm or higher. That means your engine is running 20 percent faster and burning 20 percent more fuel.

Living with that 2 minute commute extension will save you (depending of your mix of highway and city driving) up to 20 percent at the pump. So, if you’re filling up after 500 km, you can now enjoy an extra 100 km and fill up each 600 km instead. That’s a good deal, if you ask me. That 2 minutes extension is saving you hundreds per year.

Think about it.


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4 Responses to Speeding costs more than it’s worth

  1. Lisa says:

    I’ve often heard that driving faster uses more gas, but this breakdown really puts it into perspective. Thanks for the info, and inspiration!

  2. Marc L. says:

    This math is so wrong that I would have to spend all day correcting it. The engine does NOT work 20% harder for 20% more speed. Even if it did, engine work does not equate fuel efficiency. Fuel efficiency is dictated by several factors: engine efficiency, transmission gearing, ECU fuel maps, total weight displaced, etc.

    So what’s the real answer? It’ll be different for every car. On my car (Mercedes C230), the real world difference between 100km/h and 120km/h is about 3% (6.9L/100km vs 7.1L/100km). Hardly anywhere near 20%.

    So next time you want to spew out some numbers, try putting it to the test first instead of making things up. It’s not hard. Fill your gas tank. Don’t top up past the click. Drive 100km on cruise control @ 100km/h then go refill your tank. See how many liters you really used. Repeat for 120km/h. Compare. Cry in pillow about how you need to come up with a new idea for article because it didn’t pan out.

    Since your readers come here expecting to see fuel savings tips, I will leave you with some real ones:

    - Keep your tires at the proper pressure. You’ll be amazed what this alone will do.
    - Take your winter tires off. Seriously. It’s not safe, and they won’t give you any grip in the heat.
    - Stop braking late. See the light change to red 1km down the road? Lift off the gas right away and coast to the light. You’ll save gas and brake pads, and you won’t get there any later.
    - Take the junk out of your car. Extra weight reduces fuel economy.

    I guarantee you that these tips will net you far more fuel savings than the 3% you’ll lose from driving 120km/h.

    • Jen says:

      Marc, thank you for your very blunt comment. I think it would be best for me to quote a friend of yours in my response:

      Increasing speed means you must overcome more friction (this is a linear increase but only a linear increase in friction costs so if friction costs you $1.00 per trip then increasing speed by 20% will indeed increase the friction cost of your trip by 20 cents) you must also overcome wind resistance, this is an exponential increase, so the cost of wind resistance might be very low at low speeds it is quite costly at higher ones. Since each vehicle is aerodynamically different in this case, some vehicles might see a 20% increase in costs for increasing speed by 20% others might see less or more.The good mileage cars get good mileage at high and low speeds. You are talking friction based costs. Those costs are at a direct linear relation to the velocity of the vehicle (and completely supported by the above article) . It all goes out the window at higher speeds (aerodynamics determine the speeds that matter).

    • Sam C. says:

      Marc L., I’m astonished that someone so wrong could have so much conviction. Even if you were right (which you are not), the arrogance you have displayed is plain ignorant. Are you as critical of yourself as of strangers? Do you converse with people face-to-face in the same manner? I strongly doubt it. Not the same as hiding behind a keyboard, is it?

      I won’t waste time quoting endless government research that shows that this article is, in fact, correct. Check the websites for Transport Canada, the California Energy Commission and the US Department of of Energy (to name a few) for support to the facts listed above. I would be happy (entertained) to see your math that helped you arrive at 3%. Did you reset your fuel monitor on that car of yours before you sought your readings? Do you perhaps not shift into the highest gear until you’re over 100km/h?

      I would be further entertained by your definition of “real world.”

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