drafting semi's

[user removed]

43 feet from the beginning of one stripe to the beginning of the next stripe. 3 stripes is 129 feet 4 is 172 feet. 60 MPH is just under 90 feet per second (1.47 feet per second = 1 MPH). 2 seconds separation at 180 feet at 60 MPH woud be a little more than 4 stripes separation which would be 172 feet. If you keep whole stripes between you then you add the length of the stripe itself. I like 3 whole stripes separation and a little to the left in the lane so the trucker can see me.

I also like to find the trucks with the rear end closed in the middle, like the UPS tandems (2 trailers). Busses are even better and towed trailers with low ground clearance. I had a trucker 15 feet off my tail today at 63 MPH with the speed limit at 60 in the right lane of 3 lanes merging into two lanes. I dont give a crap what that idiot likes or dislikes about me drafting him in bumper to bumper traffic.

In ten miles of ludricously agressive driving he managed to get 200 yards ahead of me. I was tempted to call the number on the back of his rig and report him, or even take a couple of pictures of his stupidity and send them to the company.

Normally it's a more symbiotic relationship.


regards
Mech

[Jakins]

Back when my civic was averaging like 38 mpg normally, one time I went on a 40 mile trip, filled up about 6 or 7 miles from the free way so I had a little city driving, and when I got on the freeway a drafted an 18wheeler like 1-3 car lengths behind almost the whole way and pulled over and filled up and I got 55 mpg. Best I'd ever done. That was without any mpg gauge but now I'm sure I can do way better. It worked for me. When I was up close I stuck my hand out the window and felt almost no wind resistance. Also in the very rare occasion that you have a truck next to you and in front of you, there is like no wind resistance at all

[Sven7]

One to three car lengths is suicidal.

[Jakins]

Maybe i was exagerating. i dont remember. I don't want to sound like a douche but our cars have way better stopping power then a 18wheeler. I try not to stay way to close to where the truck driver gets frustrated and uncomfortable and starts trying to scrape me off the back of him, but I do like getting close enough to feel a difference. What I'm doing is deffinetly reasonable. All though I deffinetly make some pretty bone headed disicions on the road at times

[Sven7]

Yeah, I did some of that **** last year as well (Got me almost 90% over EPA), but now stay at least a couple seconds back. It's just safer, and follows the golden rule.

[serialk11r]

Originally Posted by Sven7

One to three car lengths is suicidal.

I guess over in California we already have "car trains" or "road trains" then. 3 car lengths is the point at which someone tries to squeeze in between you and the next person when there's moderate traffic, still flowing at 60mph+.

[UltArc]

Didn't want to post this as a new thread, it seems wasteful- but wanted to post this as I was just watching the myth busters and they calculated it in a wind tunnel- not meaning it is perfect, but it is definite that drafting works. To my knowledge this hasn't been posted (or I missed it, or it was before my time here and I haven't found it yet).

Some data:
21% drag reduction when 7 car lengths behind a semi truck at 54 mph, in the model wind tunnel.
10 feet away, 60% reduction.
6 feet away, 80% reduction.
2 feet away, 93% reduction.

The following was done on a controlled road, it was same direction. No mention of wind, engine temps, so on. NOT ABA, just the control, then each other calculation. Vehicle in question is a Dodge Magnum, 2.7, I believe.
Driving @ 55 mph gave 32 mpg
100 feet away 35.5
50 feet away 38.5
20 feet away 40.5
10 feet away 44.5
2 feet away 41 (I believe), but not accurate by driver error.

I think it's a bit ridiculous they don't think it's safe to be closer than 150 feet behind a car at 55 mph. I understand dim people might try driving two feet away and make poor decisions, but for being in California, they don't seem to be familiar with traffic.

If anyone uses Netflix, one can watch this on Collection 4, Episode 3.

[wickydude]

Originally Posted by Jakins

Maybe i was exagerating. i dont remember. I don't want to sound like a douche but our cars have way better stopping power then a 18wheeler. I try not to stay way to close to where the truck driver gets frustrated and uncomfortable and starts trying to scrape me off the back of him, but I do like getting close enough to feel a difference. What I'm doing is deffinetly reasonable. All though I deffinetly make some pretty bone headed disicions on the road at times

It's not that cars have better stopping power. It's the fact that at these speeds and distances, your reaction time (on seeing his brake lights) is not fast enough to hit the brakes before you hit the semi.
No offense mate, but to me this sounds like one of those boneheaded ones.

[wickydude]

@Ultra, yeah saw this last year or so. Wasn't too impressed with them banging that open door

[UltArc]

Originally Posted by wickydude

@Ultra, yeah saw this last year or so. Wasn't too impressed with them banging that open door

Sometimes they seem a bit weird...kicking that door, if you are talking about when they were trying to activate that air bag, doesn't make total sense. For some reason I imagine not every single side air bag has been that design, and they don't always look totally into it...like when the air bag guy was sitting there and asked how they plan to do it, since that particular air bag was actually inside the car...

But since they had somewhat of a scientific approach, I thought I'd post it up somewhere.