I would rather spend a bit more for gas and drive safely. When you are behind a big truck your field of vision is blocked and that is very dangerous. 3 seconds or 240ft behind a truck is not enough of a space cushion to prevent a crash.

AAA says "at highway speeds, a 2- to 3-second following distance will not give you enough time to stop if the road ahead is suddenly blocked. At 55 miles per hour, you would need at least 4 to 5 seconds to stop the vehicle to avoid something in your path of travel. Therefore, your position in traffic should be based on availability of escape routes."

AAA further says "If your vision is blocked by a large vehicle such as a SUV, van or truck, increase your following distance to 4 seconds. This extra distance will give you better visibility."

"Drivers must learn to look at least 20 to 30 seconds ahead. At highway speeds of 50 to 65 miles per hour, the 20- to 30-second visual lead time translates to one-third to one-half mile," says AAA.

Be safe on the roads!

What are recommending it extremely bad advice. The safety hazard is not nearly worth saving a few bucks on gas.

My older brother who has been driving 18-wheelers across the United States and locally for 10-15 years has always told me to stay as far away from trucks as possible! After witnessing fatal accidents caused by trucks, a tire blow out (not on his truck luckily) landing through the windshield of a Jeep Grand Cherokee (was fatal), and numerous other bad truck accidents, he always tells everyone to say the h#ll away from them--only bad things can happen.

-Robert

Mythbusters covered this a few seasons ago. They came to the conclusion that although driving a few inches behind a truck saves some gas, any more than that is useless. Driving that close is also very dangerous and not worth the benefits.

I fail at skimming

I keep as far away from trucks as possible on California roads. Fortunately, most of my travel is on roads with 3-4 lanes so I have little interaction with big rigs. In a few short years that I've lived in SoCal, I've seen first-hand numerous items fly off of trucks (ie. tires, oranges, rocks, boxes, etc.) and seen my share of accidents involving larger big rigs and passenger cars. Its not pretty.

There might very well be a safe distance to follow a truck and save some money on gas. But like other supposed tips I've read about (ie. shedding a full size spare, buying cheap tires or brakes, not regularly maintaing your car, etc.) it doesn't seem like the risk, however small, is worth the reward. Especially for cities like LA where we are virtually married to our cars.

I think the entry here covered the fact that following too close is not safe. I was worried when I first saw the title, but you really covered your thinking about why it would be a trade off that any adult responsible enough to be reading a personal finance blog can interpret as a bad deal. The threat to health is too high to allow for this idea to be truly feasible. You have provided information from both sides and I applaud your efforts. I'm disappointed to see some of the other comments discouraging your information because I doubt they read the whole entry before becoming offended.

Xin Lu is asking anyone to use trucks as a means of saving gas.  I think she is simply letting people know of a good way go a little slower than the average driver without causing a traffic situation (or getting flipped the bird.)  As a general rule, the truckers I know are very good at what they do.  Following them from a safe distance (i.e. driving in the same lane as them, not tailgating) has many benefits.  They generally know the road, and other drivers are less likely to cut in front of you to get behind a truck.  In my city, if you leave a safe driving distance between you and the car in front of you, it is perceived as permission for another car to cut in and secure the space (which is very dangerous.)  Trucks own the road here, so I think of them as the older brother of the highways.  Works for me.

BINGO!  I couldn't have said it better....

Not to mention the obvious safety hazard of following a truck closely, it's worth mentioning that you'll be braking a lot more frequently than if you were coasting along at the speed limit in the faster lane, which might defeat the purpose of saving money.

In my view it's not worth it unless the highway is congested already.

I never thought about drafting behind a truck to save on gasoline. But like everyone else has commented, it is too dangerous to do.

Everytime we drive, we are taking a risk. Last thing I want to do is add to the possibility of an accident happening.

Get off your high horses.

Rush hour in any city makes it completely impossible to follow at a "safe distance". No matter how hard you try, someone will always cut you off and take away the safe distance between you and the car (or truck) in front of you.

I totally agree with Linsey and Ryan. I live in Seattle and I have to commute through about an hour of traffic and the stop and go always seems to stress me out. Over the past few months, I've learned that following (yes, a safe distance) a truck's lead not only saves gas but also lessens the overall stress level when commuting to school. Trucks to me do seem like wise big brothers because they, like Ryan previously mentioned, seem to find a happy medium when it comes to speed to avoid all of the hectic stop and go mess. Great article! I was surprised to find a great amount of negative comments.

What kind of idiot is going to follow a semi-truck at about 5 car lengths and not get antzy about it? It seems to me, at best, suicidal... let alone, illegal. Talk to a truck driver at a truck stop and see what information they have for you. How about the fact that some of the worst accidents involving trucks are the ones where cars are not following at a safe distance, or do not take into consideration the difficulties that truck drivers endure just having to share the road with these fools. I beg to disagree, the best way to save gas is not to drive.. If you must drive, do so intelligently using other fuel-saving measures, like slowing-down....
How would this person like a civil law-suit on their hands because they are recommending that prople follow at a unsafe distance? I, as well as my family, don't think this strategy is worth the price of a life. Especially if the life is someone elses and you have to live with that responsibility.
Choose your words and recommendations VERY carefully, my friend.... There WILL be people that will follow these instructions.... I just hope I never see them.

It seems a lot of people are only reading what they want to read (I'll admit I read the header wrong at first too, until I thoroughly examined the article), but Xin is not advocating that you jeopardize your life by directly driving behind a semi. Sure automotive accidents may happen from trucks, but there's an even greater number of risks from driving alongside drunks, street racers, sleep-deprived/cellphone engaged people.

Take from this article and some of the comments what you will. I live around the Los Angeles area wherein people are always in a hurry and thus our glorious traffic jams. I've noticed on occasion on highways, the left-most lanes will be dramatically slow but the entry/Truck lane is constantly moving. Ironic how those lanes are supposed to be for faster moving traffic. We all want to be in constant moving traffic as opposed to stop-n-go traffic, but remember as everyone before me has mentioned, keep a safe distance while driving.

This "Apparently driving behind big trucks also saves you gas due to something called drafting, and you can safely take advantage of this to save an additional 5 to 10% of your gas." is a complete guess and completely wrong. To get any sort of efficiency you would have to be TOO CLOSE. 100 feet is not enough. You going off and GUESSING 5-10% efficiency is wrong. No, you cannot draft at a safe distance.

This is an astoundingly disappointing article. The only decent point (drive behind slower trucks to keep yourself at a slow speed) was barely touched on, then there's focus on drafting for three paragraphs. You cannot draft at a safe distance. At a safe distance you are out of any drafting efficiency.

I understand everyone's comments regarding safety concerns.

Even at a safe distance, I've been the victim of having trucks pick-up stones and loose debris on the road. Last year alone I had to repair my windshield 3 times. The year before that I had to replace the windshield.

This is the dumbest personal finance advice I've ever come across.

I'd rather skip my latte.

At what speed or rpm is considered best for gas saving while driving our freeways. I us cruise controll when possible and try to set it at around 60(sometimes up to 64 - I know I'm breaking the law when the limit is 60). I drive a Saturn Vue and am passed by many long haul truckers.

I drive a flatbed 18-wheeler...

The vehicles we fear most on the road, are you 4-wheelers... especially you soccer-moms in your SUV's, talking on your cell phone, and feeling invincible.

In the winter time, whenever the roads get too slippery, without fail, the kinds of vehicles we see spun off the road the most, early on, are the SUV's... we'll see probably a dozen of them, before we start seeing other vehicles get taken out as conditions get worse...

Anyways, just a mini-rant there.

You all need to understand... we're not the unsafe drivers on the road... we go through several weeks of training, before we even climb into a rig and spend several more weeks of road-training with a trainer before we're let loose by ourselves...

Any idiot can get a license for a 4-wheeler, with 75% or 80% on the test, which is usually only 20 questions.

These idiots will do just about any stupid thing you can think of on the road.

One recently, as I moved into the left lane to pass a slower truck, a white SUV (>sighs<) was racing up in the right lane to try and get through before I caught up with the slower truck, and just didn't make it and had to slam on his brakes when he ran out of space between us just as he got up to us... once I finished my pass and moved right again (only after the passed truck, signalled to me that he was cool with the space he had in front of him), the idiot in the white SUV raced past, flipping me off as he did, like I was the idiot.

If you spent time watching the trucks on the road, especially when they interact with each other, you'll start to notice that there is a lot of communication happening with each other. A lot of it is over the radio, sure. We usually know of an accident, a closed lane, a blown tire in the road, even a 4-wheeler changing a tire on the shoulder, miles in advance before we get there. (we also know of the idiot drivers coming up behind us, miles before you get to us... you know who you are.)

The radio communication is only about 1/4 of the communication happening tho.

Most of the non-verbal communication is in the light-codes we use with each other. We tell each other when they can come back in after completing their pass, thanking each other for what the other driver did earlier, if they have a problem with their securement and should pull over, if they are cutting in too close, and even if we're about to make an evasive maneuver for something we see in the road ahead, if it is a tire carcass, chair, or dead deer in the road, or emergency vehicles or broke down vehicles on the shoulder.

We know what to expect from each other, and we know, the other big-rig drivers know what to expect from us.

Even something as subtle, on a 2-lane highway, as the truck in front, moving in his lane, a foot to the right, can signal to the truck behind, that the road ahead is clear for him to make a pass, while, if we're hugging the left side of the lane, he sees an oncoming vehicle, or something else making the pass unsafe. He's basically letting you see past him, or blocking your view. We'll do the same thing for 4-wheelers behind us. Some of us will also flash our running lights on and off after the last oncoming vehicles comes by to signal the road is now clear, and make your move. Not all drivers do this signal tho.

We also, have larger stopping distances. I mention this, for the 4-wheelers that have a habit of pulling in front of a truck, with the 'safe' distance that would be ok if it was a 4-wheeler.

Big rigs, take a MINIMUM length of a football field to come to a complete stop from 55mph, on level ground, with perfect road conditions, and a heavy load which makes their brakes work most efficiently. This isn't a nice stop. This is an emergency stop. One that has a good chance of dislodging the load. Even more so if the load is coils or bundles of pipe.

Running past the truck just to jump in front of him to try and make that ramp you're about to miss, scares the hell out of truck drivers, as the 4-wheeler doing this maneuver, usually slams on their brakes as soon as they're in front of us, to make the ramp. When this happens, I'm simultaneously slamming on my brakes (which take at least a second to activate... air-brakes aren't as responsive as hydraulic brakes), and hitting my hi-beams, signalling TOO CLOSE!!!

The particular event I have in mind, I couldn't even see the back of her... yes... another SUV... I only knew she was on her brakes when the middle light at the top came on, and if she hadn't darted out of my way onto the ramp when she did, she'd be getting cut out of her SUV a while later.

If we're empty, it takes us longer to stop. Seriously.

Our brakes are most efficient with a heavy load. That's what they're designed for. When we're empty, it doesn't take much for us to lock our brakes up, and lose our stopping power, jacknife, fishtail the trailer, or even roll over.

Ok, I went off on a few tangents, I'm sorry, but I was inspired for a few minutes.

Back on topic... :)

When I find a 4-wheeler tailgating me, my response is simple.

Every few seconds, I tap on my cruise control, dropping my speed by 1mph every 10 seconds or so, until the drafter gives up and goes around.

A 4-wheeler getting on my good side? If I'm passing one, and when I'm ahead of him and ready to move in front of him, if he flashes his headlights at me (on and off, not high-beam to low-beam... high-beams mean danger, remember?), that simple act of road-frendliness tells me he's a driver that gives a damn about his driving, and respects the other vehicles on the road. Even the particular needs us big-rigs have. That 4-wheeler will earn our appreciation, and even a little bit of our respect, for driving like a professional. And, we may just acknowledge that, and say so, by giving him our flashing running-light code back at him, in thanks.

-- Smoovious
(currently at a truck stop in Salinas, CA)