Slipstreaming for better mileage?

I notived a small increase in MPGs, but only when I was pretty close to the leading vehicle. Eighteen-wheelers leave a huge wake, so following distances can be increased and still show benefit, but at those speeds you're within the 1-carlength-per-10-MPH rule and your windsheild is susceptible to rock chips.

The Prius is so slippery to begin with, the difference was negligible.

 

I agree with Boxster, it is more dangerous to your vehicle than it is beneficial. I recently did MPG-vs-MPH testing, so I knew what 'normal' was for my vehicle. Just after that, I just happened to slipstream behind an 18-wheeler for most of a 100+ mile trip just to see how much of an increase there was. I always watch my consumption screen (by far the most interesting screen on the Prius!), and although the resolution of that screen sure isn't great using the bars, I only noticed a couple MPG increase over normal as time went by. I was only a "couple to a few" car lengths back, I doubt he could see me in his mirrors. I probably could have gotten the same increase by simply slowing down 2 or 3 MPH. It isn't worth it.

By the way, as an aside, I did notice truckers have vastly improved cruise controls. I only had to vary rarely change mine up or down 1 MPH. I was impressed!

 

not to mention the tons of emissions your exposed to by following these beasts.

 

the impact on mileage is very large.

i doubt that it will outweigh the $101 ticket though. currently WA state has emphasis patrols for this very issue. mostly as a result of accidents, inertia, and revised motor vehicle codes.

 

A little while back, the third semi tire to explode (OK, 'rapidly deflate') when I was nearby happened. I was maybe 200 yards behind the semi but I felt the impact shake my Prius. In my Kia a few years back, I wasn't even up to the cab while passing a semi when a rear tire went, and I thought I'd hit something. Back in the 80's I learned why keeping the windows closed sometimes keeps flying rubber from getting in your car.

Turned me right off the idea of drafting, or even hanging around a moving semi very long...

 

It's pretty dangerous, but I've found it does actually help.

This probably goes into the "guilty pleasure" category.

On a side note, I heard that there was a contest for best mileage once, and for kicks Car & Driver picked up a manual Insight, got their hands on a truck, and had the Insight slipstream it... ended up getting over 100+ MPG easy. .

 

Drafting is a habit that I need to quit. It's very addictive.

 

Being that I am a Prius owner and also a truck driver, I'll give everyone the heads up.

If you aren't talking to the truck driver via CB and have his permission to slipstream, (more commonly known as Drafting) I wouldn't suggest stopping that practice immediately. This is a real quick way of pissing him off. Someone said that “I doubt he could see me in his mirrorsâ€, and that is exactly right. Although I am able to control my aggravation in situations like this, not all truck drivers do. I am surprised that “Wayne†didn’t find himself in a predicament with the truck he was following and a couple of other trucks that the other driver was talking to on the CB.

My suggestion would be to quit this practice. If you have to do it, talk to the truck driver and he might let you draft him, but this is still very dangerous. I was doing this once (not anymore) while driving a truck and the guy I was following hit a deer. All he had time to do was say “HANG ON†on the CB. Make a long store short, we stopped and checked our trucks over, cleaned are shorts, and were on are way. If I had a car like the Prius, it would have been a different story.

So do yourself a favor, slow down, enjoy the scenery and keep a safe distance between you and anyone in front of you.

 

Hey, I just did it as a test. I would have been happier if you used one of the people touting it as a way to drive as an example. I said don't do it.

 

I agree and think it can increase fuel economy, but the problem is that you need to be right on top of them for it to really be effective. 1-2 car lengths max, which leaves you very little room for error.

Just look at Nascar - these guys are inches from each other - granted, they aren't the same size as an 18 wheeler, but you still need to be close - not inches, but feet would have the biggest impact.

As others stated, is it really worth it? Not in my opinion. I value my life and my car more than a few extra mpg.

 

The ticket is a minor concern compared to the cost of having one's head sewn back on after driving under the truck's trailer a few feet too far.

 

Can they do that these days? <_<

 

I've been drafting for a couple of months now and have settled on the following technique:

1. Sixty-five MPH is the max speed at which I will draft. As a rule, I don't drive my Prius over 65 in any case because mileage drops rapidly above that point.
2. Large commercial trucks and buses provide the greatest benefit.
3. Most importantly, I work to space myself behind the host vehicle (traveling at or less than 65 MPH) to the count of, "One Mississippi -- Two Mississippi." I am able to glean some advantage to my fuel economy at this spacing while staying a relatively safe distance back and greatly reducing rock chip damage. One does not have to drive mere feet behind the host, as was stated in other posts. Don't do it!
4. At any time, if the Caution and Warning sensors start going off in my head (which I desire to keep snugly attached to my neck, thank you very much!), then I call it off. Also, if road debris starts hitting the car then I call it off for obvious reasons.

I believe this to be a balanced approach to drafting as it minimizes danger to myself, the host vehicle driver, and others on the road while boosting my cruise mileage 5-10 MPH over solo driving.

Do I recommend it for everyone? No.

 

I feel that drafting is a much safer way to increase your gas milage . . . compared to being out in front trying to ride the bow wave.

 

Let me know how many Mississippi's you get out when he straddles some debris in the road with his feet of clearance and you run over it with your inches of clearance.

I'm trying not to pick on any one individual, thou it may seem like it. Just want to point out what can happen. It's just not worth it.

I DO NOT recommend it for anyone!

 

All you draters out there - could I be listed as the beneficiary on your life insurance policies?

Thank you, thank you very much!