Fuel Economy Tip – Tailgating Doesn’t Help

Today’s tip won’t help you save much gas, but will help you stay out of costly fender benders which, if you ask me, is just as good.

Tailgating doesn’t help your fuel economy, so go ahead and stick to the two second rule.

A couple of people have emailed me and asked whether or not tailgating is a good way to help save gas. One person even asked if “drafting, like what they do in Nascar” could increase your car’s gas mileage by a sizeable amount.

While the theory is sound, I’ll give a couple of reasons why tailgating probably isn’t the best way to go about increasing your car’s fuel economy.

In going back to the Nascar comment, “drafting” really isn’t relevant to us normal drivers. In Nascar, or other forms of motor racing, cars are driving inches, if not millimeters, from each other, and that’s how they’re able to benefit from drafting. Even the most aggressive drivers don’t tailgate that closely on the street.

Also, at some Nascar tracks, the cars are traveling at over 200 mph, so the cars have to use a lot of energy to be able to cut through the air. That’s why drafting is so important; by being on the bumper of the car ahead of you, your car doesn’t have to use as much energy to go as fast. While driving 60 mph on the street may sound fast, you don’t use nearly as much energy to get up to and maintain speed so drafting / tailgating isn’t as beneficial or necessary.

Finally, tailgating will exponentially increase your risk for an accident. By driving closely to the car in front of you, you are decreasing the amount of time you have to react in case you have to stop or swerve. Go ahead and stay at least two seconds behind the car in front of you so you can have enough time and distance to properly react.

While tailgating may be a great idea when you’re driving 200 mph on an oval, it probably isn’t the best way to save gas when you’re driving through the neighborhood.

Comments

  1. If you draft behind a semi, you’ll get some serious fuel savings.

    Those trucks are big enough to punch a giant hole in the air, which is why they drive in convoys.

  2. Robert Gray says

    Have just completed a 3000 mile cross country drive on the interstates with an SUV with a 10 sec MPG re-comp capability. We did days of drafting experiments.

    +++ car in front – 2-3 MPG increase
    +++ Semi in front – 40% MPG increase
    +++ Semi with irregular load in front – up to 100% MPG increase

    Contrary to the main posting 70-80% of the drafting effect is obtained at 100 and 200 feet distance from the front vehicle. It gets better as you close the gap, but there is serious advantages of drafting a safe inter-vehicle distances.

    Without drafting we got 11.5-14.5MPG, drafting took us to 16-28 MPG as
    described above. The effects were proven multiple times in each cincumstance. Speeds were 60-80 MPH.

    • zack kenyon says

      thank you for posting a scientific response to this nutjob. Although your methodology has a few problems. Do you drive the same way while not behind a semi? This is about 5 years late, but I have been doing my own study in my miata. I have a 70 mile commute twice a day and with gas at 5 dollars a gallon, it’s worth taking my adderall right before I drive and focusing on the brake lights in front of me if I can get 30-40% mpg increase out of it.

  3. George M says

    i drive a semi for a living. Drafting is really dangerous for everyone on the road. If any one drafts behind i will warn them a couple of times by flashing my lights and stub braking. If you dont get the hell off my tail i just drive the curb a few times and spew all the gravel and dirt at you. Go on keep drafting and lets see who wins!! You guys dont understand you are messing with our livelihoods and ways for us for feed our families. Anything that increases those odds for us on the road is a NO NO. GET IT. NO DRAFTING

    • Some guy who also drives trucks says

      Jackass. More than likely your dumb ass will cause the accident. Focus on keeping your butt on the road and just drive. It wont forever end your oh so important career as a trucker to have a tiny car buzz around your bumper, this is so damn laughable i cant believe what i just read

  4. JDinDallas says

    I just drove from Austin to Dallas behind a semi the whole way at distances from 5 feet to 20 feet in front of my suv. since an 80000lb rig cannot possible slow at the rate of my 5000lb suv at full abs panic breaking there is no way possible by physics i can hit a rig that is in front of my when my speed is equal. even human reaction time taken in to account my truck still will stop well before hitting the rig. i did have one panic stop in waco when there was an accident. i never got closer than 10 feet. all you have to do is focus on the tail lights and have a foot over the brakes at all times. that said My suv normally gets 18 on the highway and 285 miles to the tank. I have 392 miles on this tank for an average of 25.29 mpg and thats with over 100 miles mixed urban driving once i arrived in Dalles. whichs means i had to get over 28 mpg on the highway. this is simply too good not to do. i had my pedel at idle to less than 25% the whole way. besides at this distance even driving on the side of the road to spew gravel all over as was mentioned only puts gravel in my tires and grill cover buck O. i have a hood bra and head light covers so who cares if you want to run off the road and risk a blow out i still will stop b4 you even jack knifed. i think the real reason you riggers dont want drafters is that there is no free lunch in the world of physics. the mileage increase i saw was paid for by increased fuel consumption by the rig in front of me. follow the money there children is the real reason riggers dont want you drafting they dont want u to take mpg from there tanks.

  5. bushwacker says

    go ahead and follow that semi on there back bumper. just remember, most trailor tires are retreades. when one of those tires blow at 200 lbs a piece and make a converable out of your suv or wores yet kills some one in your family. dont get mad at the truck driver. your the tight ass that had to save a dollar and put your family at risk, not the trucker.
    buy the way as a driver we dont much care for you four whellers tailgating us . so dont be supprised when the truck suddenly slows, its called a brake check.

    have a great day and i hope to see you on the road

  6. Robert Gray says

    So “George M” and “Bushwacker” – you are both disingenuous and hypocritical in your replys – you can’t both advocate for road safety and at the same time do and or threaten dangerous actions. And…is it entirely an illusion that caravans of semis routinely roam the interstates practically bonded to each other both drafting and tailgating? You may want to believe that there are one set of rules for you and an entirely different set for the four wheelers. It will never work that way. Responsible drafting DOES work, and I dare say that fuel saving is entirely the motivator for your own tailgating and drafting. You need to walk the talk, first. For me…my SMART car has finally arrived and moving less mass is truly the safe and responsible way to higher fuel economy. Best non-hybrid mileage and a price point at about 1/2 the hybrids. See you safely on the roads.

  7. I’ve been behind George M and bushwacker on the highway. Bushwacker slammed on his brakes a couple of times nearly losing control of his rig then pulled over on the shoulder. I was laughing as my exit was less than 1/8th of a mile up the road and he was going to burn a chunk of fuel to get back up to speed, and for what? George M kept slowing down, eventually to thirty five mph or so. I just put my flashers on and thought about the great mileage I was getting at that speed till he pulled over on the shoulder. Guess what? My exit was 500 feet in front of his truck.
    I keep a car length per 10mph back and I know I’m taking a chance of catching a gator.
    Following you isn’t any skin off your back, what’s your beef? You drivers need to pay attention to driving you rig and what’s in front of you, not what’s behind you.

  8. I’ve been behind Sam on the highway. He was tailgating a semi because hes a cheapskate trying to save some money on gas. After a few miles the semi had to come to a quick stop because a suv merged too close to his truck from an on-ramp. Well needless to say sam rearended the semi. Now sams gonna need a tow to a mechanic shop, and a rental vehicle. Hope fully the money he saved on gas will cover the increase on his auto insurance and the lawsauit hes gonna get for putting a trucker out of work for a few weeks. That is if Sam is still alive after the accident.
    And all of that for an extra 10 or so mpg? Dont be retarded, keep a safe distance from semis.

  9. I can understand truckers if it is taking away from their gas mileage. The safety issue is ridiculous. Today some truck driver nearly caused an 8 car pileup cause i was driving 20ft behind him, he apparently thought it was too close… slammed on his brakes, swerved back and forth, and brought the entire freeway to a 25 mph violent halt. Im a very safe driver, i drive like an old lady, and decided to search the internet to find any reason that i shouldnt be doing this. Seeing that trucks take much longer to stop gives ample time for the car behind to stop as well. Control issues of a maniac truck driver slamming on his breaks is what is dangerous. But if its taking away from their MPG… i understand why they would not want anyone to tailgate them.

  10. When you tailgate you have to brake more frequently, which wastes fuel. If the vehicle in front slows (whether by braking, or easing off, or encountering a hill), then you will often find yourself braking to stop going into the back of them. If you leave a sufficient gap you can adjust your speed without braking. (Every touch of the brake pedal is wasting fuel, because you’re converting your kinetic energy – produced from burning petrol – into friction and waste heat).

    This is also how ‘phantom tailbacks’ occur. A vehicle slows because of a hill or some other reason. The driver following closely behind has to brake. The following driver brakes even harder and so on until somewhere down the line the traffic comes to a standstill. If the vehciles are well spaced out then this phenomenon doesn’t occur.

    When you tailgate you need to be much more alert to be able to react to the vehicle in front braking or slowing. This increases stress and driver fatigue. It can also create stress for the driver in front, especially if they are a vulnerable road user like a motorcyclist.

    So many rear-end collisions are the result of tailgating and the following driver not having enough time to react and to brake.

    Overall there can be no justification for tailgating. It wastes fuel and increases accident risk and stress for both you and fellow citizens.

    “Only a fool breaks the 2-second* rule”.
    * 4 seconds in case of wet/icy conditions or poor visibility

  11. I know I’m late to the party, but Mythbusters confirmed this in July 2007. With a baseline of 32MPG, percentage of fuel savings at four distance settings is as follows:

    100′ = 35.5mpg = 11%
    50′ = 38.5mpg = 20%
    20′ = 40.5mpg = 27%
    10′ = 44.5mpg = 39%

    Tailgating does help fuel economy, so this article is incorrect. The author would have been better advised to cover the safety risks rather than writing on a topic he knew little about.

    My own experience with this technique has yielded 30.9% improved mpg (55mpg vs 42mpg) in a 2006 Honda Civic while keeping between five to six car lengths back at speeds between 65mph and 72mph – generally over a 132 mile route.

  12. Really, if you can’t maintain a 100 foot distance without constantly hitting the brakes or running into the back of the semi, you should not be driving period, let alone drafting.

    Truth is I have drafted quite a bit, and you can save gas and maintain a safe distance behind the truck. Your are not always tapping the brake, trucks ahve cruse control also. they are going to maintain a steady speed most of the time. The stopping distance of a modern car is about a third of a truck at 60 mph. ( 500-550 on average for a semi, 150-200 for a car.)

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