Drafting - pros & cons

[DonEaston]

Hello everyone:

I was wondering how often you all take advantage of drafting when on the open road, or freeway.

I've never been able to do it long enough to get any numbers, but it REALLY seems like I use a lot less fuel when I can get on the freeway and "snuggle up" behind a semi truck. The same seems true for my truck and the Jeep, but especially the Jeep. (maybe because the gas gauge sticks like a sonofagun on the truck)

Okay, just wondering what your feedback is!

-Don Fitzpat

[DrEMHmrk2]

I do it from time to time. If I find a truck going sufficiently fast, and one that is sufficiently stable and the traffic is sufficiently minimal, I'll draft for miles at a time. Sufficiently.

I stay back about 40 feet or so, just enough to give myself some reaction time. At 75MPH my factory fuel economy meter (which has proven to be very acurate based on fill up calculations vs. gps mileage) will go from about 26MPG WAY UP to 32 - 36MPG. The closer I am and the less cross wind there is, the better the figures. Also, when I can find a truck that is going at the EXACT same speed as one of the settings on my cruise control (it eats mileage to make miniature corrects over and over trying to match another vehicle.)

It's not often that all these criteria line up but when they do, it can be high mileage coasting for MILES.

[DonEaston]

WOOOOOW!!!

I NEVER would have imagined you'd see that big of a jump! My God, that is awesome! I'm pumped now... I'm going to do that more often.

Thanks sir!

[bestmapman]

Originally Posted by DonEaston

Hello everyone:

I was wondering how often you all take advantage of drafting when on the open road, or freeway.

Okay, just wondering what your feedback is!

-Don Fitzpat

The biggest problem are the small stones or gravel that chip the windshield and or paint.

[MetroMPG]

Stone chips may be the biggest actual problem, but it's not the biggest potential problem.

I don't like drafting & don't recommend it. There's no argument it works to reduce fuel consumption (have you seen the Myth Busters episode?), but I don't like to give up the ability to see ahead.

From a defensive driving perspective, when you draft, you more or less hand control of your vehicle to the driver in front of you. If s/he brakes, you're pretty much forced to immediately brake also. It's reactive vs. proactive.

This subject came up in a thread last week: Drafting off center?

[DrEMHmrk2]

Originally Posted by bestmapman

The biggest problem are the small stones or gravel that chip the windshield and or paint.

3M Clear Bra/Lamin-X is your friend. Headlights covered, leading edge of bumper, leading edge of hood, grill and mirror housings. It's kept my car free of major pits and scratches in the front for about 8 years now. When it turns yellow (about 5 or so years) you just peal and reapply.

Only your windshield is still susceptible to destruction, but in Florida the insurgence companies must replace a cracked windshield so there isn't a major concern there... in fact I still have a crack free windshield, even with my fair share of drafting, Nascar style.

[DrEMHmrk2]

Originally Posted by MetroMPG

Stone chips may be the biggest actual problem, but it's not the biggest potential problem.

I don't like drafting & don't recommend it. There's no argument it works to reduce fuel consumption (have you seen the Myth Busters episode?), but I don't like to give up the ability to see ahead.

From a defensive driving perspective, when you draft, you more or less hand control of your vehicle to the driver in front of you. If s/he brakes, you're pretty much forced to immediately brake also. It's reactive vs. proactive.

This subject came up in a thread last week: Drafting off center?

You're right, it's not the safest possible plan, but then again one could argue that shutting the engine off and letting a Dodge Caravan coast without power breaks or steering could cause you to potentially not have enough control to avoid an accident...

I'm just being facetious, but in the right situation, it may be safe to argue that a big rig driver has some of the most experience and therefore could be one of the better drivers on the road to hand control over to.


To the OP, trust your judgment, if you are behind the truck and start to feel nervous, back off and let it go. I just know that when I find a truck going the exact same speed that my cruise will click into, I draft him for as long as I feel comfortable.

[MetroMPG]

I take your point - it depends on the situation. But I'd don't think you'll ever find me saying that in general coasting engine-off in car that normally has power steering is safe. (PS. the brakes aren't the issue - there's enough vacuum reserve with the engine off for at least one full assisted stop.)

About drafting: it's not the vehicle in front that I'd be worried about in the event of an unexpected slowdown or stop. In fact I'm quite sure you're driving in a state of let's say heightened awareness. It's the vehicles behind you that pose the biggest threat.

[DrEMHmrk2]

Originally Posted by MetroMPG

I take your point - it depends on the situation. But I'd don't think you'll ever find me saying that in general coasting engine-off in car that normally has power steering is safe. (PS. the brakes aren't the issue - there's enough vacuum reserve with the engine off for a full assisted stop.)

About drafting: it's not the vehicle in front that I'd be worried about in the event of an unexpected slowdown or stop. In fact I'm quite sure you're driving in a state of let's say heightened awareness. It's the vehicles behind you that pose the biggest threat.

Thats true, you do lose your forward escape vector. Perhaps those in the pursuit of economy must decide when the safety concerns outweigh the fuel savings.

[DonEaston]

Very good points on defensive driving, and a better point about your 6 being what you have to worry about.

If you got a long train going, what you really have is a pile-up waiting to happen. And, if you're driving a Geo Metro, while an '08 Superduty follows at about 35 feet, you're looking to become the piece of bologna between a trailer and truck.

Good points- something to think about!

Drafting would be a good way to alleviate the cost of shipping goods via truck and trailer though, you know? A semi is going to get 7mpg no matter what. But if you got 6 vehicles behind it, getting a total savings of 40mpg, suddenly semis aren't that bad of a deal!