Is it possible to "draft" other vehicles on the highway to save energy? Was following my wife's SUV on our vacation last week and started wondering if doing so was affecting my efficiency. Had autopilot set to 1 which is actually more like 3 or so car lengths at highway speed so not sure I was close enough to get any benefit. Don't want to tailgate anyone on the highway, but wanted to know if anyone has figured out if there is a way to do this safely and what the benefit might be.
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Proper "Drafting" Technique?
- Thread starter Boomer543
- Start date
IMHO - Following a large truck with the distance set at "4" makes a pretty significant difference at 70+ mph.
Just watch the Wh/M gage over time.
I wouldn't put it to close. Windows are expensive.
Just watch the Wh/M gage over time.
I wouldn't put it to close. Windows are expensive.
fajitamondays
Member
Casual observation from a WA state driver, who was just in NJ visiting family recently -> In NJ, it appears everyone drafts on each other in the left lane 
Those "normal" following distances are wild out there.
Those "normal" following distances are wild out there.
Burrito
Member
NJ here, if you give more than 2 car lengths then someone will use that space. i would like to increase efficiency but dont want rock chips so i use AP at the max distance (7)
Summary from other threads on this topic:
Drafting can help. It can help a lot when there's a headwind. You run a much higher risk of rocks, debris, being sandblasted, etc. and it's really hard on paint. Most truckers HATE it. Going faster to keep up with the vehicle in front can be worse for range than driving a bit slower. It's not worth it unless you're really in trouble.
Those are the main points I can remember.
Drafting can help. It can help a lot when there's a headwind. You run a much higher risk of rocks, debris, being sandblasted, etc. and it's really hard on paint. Most truckers HATE it. Going faster to keep up with the vehicle in front can be worse for range than driving a bit slower. It's not worth it unless you're really in trouble.
Those are the main points I can remember.
640k
Member
Mythbusters had a really good episode taking about different techniques for saving MPGs, etc. AC on/off, windows, drafting, etc. They basically confirmed drafting will help you with MPGs but you'll have to follow so close, that if anything were to happen to the car in front of you or the next car, etc., that you'd have little to no time to react.
the small percentage in fuel savings isn't worth the risks and normal road debris you'd incur anyway.
Uncle Paul
Well-Known Member
Interesting thing about drafting...BOTH vehicles get better efficiency.
Tesla has been doing lots of research of the benefits of platooning for it's trucks. Using autopilot they could string many of their trucks, running close together and get a big increase in range for them all .
Tesla has been doing lots of research of the benefits of platooning for it's trucks. Using autopilot they could string many of their trucks, running close together and get a big increase in range for them all .
Agreed.
Drafting close enough to significantly improve your energy efficiency is dangerous.
There have been many threads discussing this on TMC over the years. Search for “drafting”.
640k
Member
CharleyBC
Active Member
I think the thread title is an oxymoron. Drafting isn't proper. It's dangerous.
Yes it is possible. No it is not advisable for your safety, the safety of others, and your vehicles paint and windows.
If you do decide to draft/tailgate, and run into the vehicle in front of you...please please please don't come back and say that Autopilot crashed into another vehicle.
If you do decide to draft/tailgate, and run into the vehicle in front of you...please please please don't come back and say that Autopilot crashed into another vehicle.
I do it on the interstate behind 18 wheelers. I figure I can stop way faster than they could if there was an issue. I essentially use autopilot and manually change lanes via the blinker when they do it (I turn off navigate on autopilot too stop automatic lane changes). I set the speed on the cruise control about 5 MPH than the truck's top speed so I keep up with it going down hill. It is really easy on the drive when the car is keeping the distance consistent.
640k
Member
you're joking, right?
rule of thumb with trucks (or any car): if you can't see their mirrors, they can't see you. i don't care how good autopilot is. if that truck slams in to a barrier, animal or another vehicle, you're done.
The energy you save by drafting will be more than offset by increased paint and windshield damage. I won't draft a vehicle unless I'm desperate for additional range like when traveling into a surprise headwind or snowstorm, neither of which should be surprises if you're planning your trips properly.
640k
Member
hell i have film on the front half of my car and i know this is stupid. personally i'd rather be as far away from large vehicles as possible. sedans and teenage drivers aren't the only ones distracted. i've seen plenty of semis swerve because of who knows what.
Yes drafting saves energy.
But do not adjust following distance in order to draft. Just stick to safe following distance and deal with it. You'll save a lot more energy by not crashing than by drafting.
You can get some drafting as you begin passing or after being passed by large vehicles, due to being in the wake of the vehicle. Some expert hypermilers make use of this "side drafting".
I have film on the front of my car, too. I also have some (one or two) rock chips that have penetrated the film and gone through to the paint, and that's with normal driving (no drafting). I can only imagine how bad it would be without paint protection film.
