I was poking around on the Civic forum earlier because I rented an HCH2 on a business trip this week and I wanted to see if my impressions were consistent with the owners of these cars.

Anyway, I came across a lively discussion on the subject of "Drafting". In case this term is new to you, it started back in the 70's during the last gas crisis when long-haired knuckleheads with just enough knowledge of physics to get themselves into trouble figured out that if you ride 10 feet off the bumper of an 18-wheeler, at highway speeds, that the negative pressure inside this envelope would pull you along, essentially for free.

An awful lot of people died doing this and it looks like were about to lose a few more.

I happen to work as a technical instructor to the trucking and transportation industry and this comes up in my classes from time-to-time.

What's the groups opinion on this? Do you hear of it often.

I'm all for any creative and SAFE methods of increasing FE. But it just isn't worth risking your life to save some gas.

~stepping off the soap box now~

 

I think people who do this (and turn off the engine while moving) are nuts.

I get great MPG without doing either.

Then again dead guys don't use gas to maybe that's the idea.

 

Over on PriusChat, this topic is also getting a lot of attention.

Several people are claiming that drafting 50 feet at 60 -> 80 mph saves fuel and is totally safe. In these lighter cars, just getting into the "drafting zone" requires you to fight the terrific air turbulence behind the trucks.

That problem, plus, not being able to see what is happening ahead of the monstrous trucks (IMHO) makes drafting dumb. Yeah, it takes forever for a semi to stop with it's normal brakes, BUT takes absolutely NO TIME for the rig to: jackknife; hit something, run over it, squash it and leave the remnants for you to hit; get in a multi-car/truck pile up and let you change your hard-top car into a convertible.

Me, I believe in the 2 second rule (at a minimum).

 

THREE SECOND RULE

A good way to measure your safe following distance is to use the “three
second rule.” Choose an object near the road ahead, like a sign or
telephone pole. As the vehicle ahead of you passes it, count slowly, “One
thousand one, one thousand two, one thousand three.” If you reach the

object before you finish counting, you are too close to the vehicle ahead.

 

No, no, no! The technically correct chant is "One Mississippis, Two Mississippis, ...".

 

Or to be a little more cautious, "Un Parangaricutirimicuaro, dos Parangaricutirimicuaro."

Actually, my first car was a new 1971 VW Super Beetle. I drove it from Phoenix to Tucson to check out U of A before deciding where to go to school. On the way home, one cylinder wasn't firing and I couldn't get the car above 45 mph... that is, until I discovered drafting. Once I found a monster air-sucking machine to draft, I could maintain 75 mph on just three cylinders.

I figure the semi drivers have a better view down the road, and they keep the bugs off my windshield.

 

Oh, boy.

I figured I was safe with my quoting of the "2 second rule". Now I hear the "3 second rule". What, I was wrong, AGAIN? Or did I mis-remember it? For me, it doesn't matter, I try to maintain a more than adequate following distance.

BUT -- I needed to find out!

Searched for "2 second rule" and "3 second rule":

Several knowledgeable areas will swear by 2 second and other reputable sites say 3 seconds are required! One even lists a "2, 4, 10 second rule": (first I thought this referred to the old Dr. Pepper trademark, but I digress) following times for dry, wet, icy conditions.

BTW -- Most of the hits on the 3 second rule referred to basketball shooting times.

 

I try to average around 3 seconds, but depending on terrain, traffic, and speed, I'll "migrate" in closer and farther back. On average I like 3 seconds. Any drafting at all is a little risky, but personally, I think 3 is still pretty safe. The amount of space you leave is up to you and your tolerance for risk (and your level of luck .)

 

Personally, I do not draft for safety reasons.

I'm not sure I can say the same about close-in drafting, but FASing can easily be done safely. Of course, it's not useful for all driving conditions. It certainly sounds like your commute would not benefit from it. However, it works very well for me with my slow speeds and mild hills.

I'm sure it is nice to merge on the freeway, set the cruise to 48 mph, and get great fuel economy. However, my commute is a bit more complicated that that.