3 seconds, or rear view mirrors

[Mad4Macs]

"If you can't see my mirrors, then I can't see you".
Got it.
Thing is... behind a semi, at 65 MPH, isn't keeping a 3 second gap good enough?
Over the past year, I've been experimenting with fuel economy while on the highway.
Proper tire inflation, great idea.
Anything over 75MPH, kiss of death, which bring me to...
Semi's.
By following all of the "good driving habits" known to man (65MPH, ac off, windows up), I get roughly 27 MPG.
Following a semi, safely, with a 3 second gap, I got 31 last week, but there's no way I can say that I could see his mirrors.
Too close?

[offroadkarter]

Only if you crash into him then your to close, 31mpg who cares, your getting 31mpg! hope you have some rock proof windows.

[fastblackmerc]

hope you have some rock proof windows.

And a good body shop to repaint the front end damage from all the debris that will be kicked up.

[Mad4Macs]

Two VERY good points!!!

[duhtroll]

Exactly what I was thinking. I don't go over the speed limit because I'm in a hurry or trying to be a rebel. It's that if I go the speed limit, semis sit in front of me and I get all sorts of crap kicked up at the MM. Not acceptable.

I religiously try to stay at least 1/8 mile back from them, but it doesn't work well with so danged many of them out there.

[larryo340]

:D maybe you should be in front the semi and let him push you throught the air (:banana2: like nascar)
that should be good for a couple of MPG's with no rock damage ;)

[Raudermaster]

Yea, that's not smart. If you can't see his mirrors, he absolutely cannot see you. What are you drafting? No A/C? Are you nuts? A/C is a must! I hate 80+ degrees of hot, sweaty air, not to mention on leather seats. I don't care what my mileage is as long as the A/C is on.

[ckadiddle]

Too close? Depends on how awake you are and how fast your reflexes are when the semi locks up all his brakes trying to avoid the Neon that cut him off. :)

[Bluerauder]

"If you can't see my mirrors, then I can't see you".
At 65 MPH, you are traveling at 95.3 feet per second. If you maintain a 3 second gap, that's 285.9 feet. That is nearly the length of a football field and oughta give you ample "stopping" distance. The typical and traditional rule is 2 seconds which will give you 190.6 feet of gap for stopping purposes. Don't think that the old School rule of 1 car length per 10 MPH is enough space (6.5 x 20 feet = 130 feet).

Given the dimensions and the angles, you should be able to see some portion of the trucks mirrors at about 157.5 feet but maybe not the entire mirror. So, the 2 second rule should be OK.

I don't think that there is a safe distance for stone throw or tire chunks. That's why I never follow trucks if I can avoid it. And when I pass them, I don't like to linger along side. These folks that ride alongside heavy trucks for miles are just asking for problems.

Basically, I find it to be a good practice never to ride in anyone's "Blind Spot" regardless of who they are. Move up and move past or slow down if you have to.

P.S. With regard to the stone throw and tire chunks, I was following Joe Walsh back from Milan at MV III and WDC. Mike Poore was behind me. We were on an exit ramp to I-696 when one of the right trailer tires blew on a trailer that continued straight. Separation between us and the truck must have been 250 feet easily. Even so, 5# chunks of black rubber passed between and over the cars. Fortunately, no one was hit --- but we all heard the tire blow and saw the chunks flying and were powerless to do anything but keep on motoring.

[ahess77]

At 65 MPH, you are traveling at 95.3 feet per second. If you maintain a 3 second gap, that's 285.9 feet. That is nearly the length of a football field and oughta give you ample "stopping" distance. The typical and traditional rule is 2 seconds which will give you 190.6 feet of gap for stopping purposes. Don't think that the old School rule of 1 car length per 10 MPH is enough space (6.5 x 20 feet = 130 feet).


I would use a stopwatch to verify that you're really 3 seconds behind, I suspect most people who count off 3 seconds are counting too fast. 286 feet is a long way behind a semi and I doubt you're getting enought draft at 65mph to get the MPG numbers you're seeing.

I prefer not to follow semis, they're not usually running +15 mph over the limit. But when I used to drive an old Cadillac I got good fuel economy by following about 2 car-lenghts behind. That's well inside the draft of a 100" tall trailer. Definately not safe, but not enough to dissuade a poor college student.

[Mad4Macs]

I would use a stopwatch to verify that you're really 3 seconds behind, I suspect most people who count off 3 seconds are counting too fast.

I'm somewhat unusual. For seven years, I worked for one of Detroit's oldest photographers (in her darkroom)... and for me, especially, "one second" sometimes equates to a lifetime.
At least it seemed that way, when being "one second off" in making an exposure would cost two weeks pay :o

[Master]

Here is an example of what happens when you travel too closely to a rig, as I can attest since I was driving it. I was leading a small import convoy - slammed hondas, in fact, and came over the crest of a hill in Newfoundland. In front of me was a basketball sized rock. Before I could grab the two-way, I shot over the rock. With a sick feeling I prayed that the undercarriage wouldn't snag the rock and lauch it window height at my friend in the Honda. Somehow, and by what must have been micrometers, I cleared the stone. The Honda, however, travelling too closely behind me never had so much as a chance to avoid the rock when it appeared out from under my trailer. It went through that little Honda like an exocet missile on a British Battleship. One end to the other, it anhialated everything it touched. The little car was launched in the air like it hit a land mine. It was UGLY!
I can't imagine this happening to one of our cars. Whatever you do, keep safe gaps!

[Herco23]

I would think that if your concern about MPG, then buy a Hybrid

[Mad4Macs]

I would think that if your concern about MPG, then buy a Hybrid


:puke:

Nah, it's just that I've put 27,500 miles on the car since November, and I was experimenting and seeing about saving a couple $$$.
It's not worth a rock in the glass, though!
Anyway...
It was a real eye opener to discover just "how much" wind resistance affects your mileage. I bet if I really tried a NASCAR style draft, I could have gotten 35MPG from a 300 HP V8!
:lol:

[Master]

I think Corvettes pretty much do.

[duhtroll]

Owning a performance car and wanting better gas mileage are not mutually exclusive.

Since we don't care about MPG let's all just get 8MPG or less. Hell, if it were only about performance, we would be driving vettes and stangs in the first place.

Wait, we could drive a Prius and get both!




I would think that if your concern about MPG, then buy a Hybrid

[Mad4Macs]

Wait, we could drive a Prius and get both!

From what I hear, the Prius posts some pretty awesome 6FT times :D

[Canadasvt]

3 Mississippi's is long enough. I know a guy who thought it was perfectly safe and legal to be as close to the vehicle in front as long as he could see the road beneath the tires. I quickly explained to him that was only when stopped.:bandit:

[Bigdogjim]

Running the New Jersey TurnPike for 2 weeks now I can say you will do better at 61MPH:)