Gas mileage
Pro
Joined: Jan 2022
Posts: 689
Likes: 245
From: Spokane Wa.
Yep. I sure did. Did YOU read what I wrote? Did you read your own site and apply any actual thought to the data they provided? 
Their analysis said:
"...we were able to confirm our initial assumptions. Both drag and lift can be reduced by decreasing the following distance behind a truck. However, to get any noticeable reduction in energy expenditure, you would have to follow at an unsafe distance for a human driver’s reaction time. To gain any benefits in fuel economy, you would be putting yourself in danger of a collision if the truck came to a sudden stop"
What *I* said was:
Are you saying that (a 34% reduction) is not a meaningful reduction in drag?
...you didn't answer that.
As for that site's claim about safe following distances, I'm going to call BS on that. First, it's totally subjective w/no reference (distance) that I saw. They just say, "it's unsafe". BASED ON WHAT?! Nothing, that they provided. A Corvette will handily out stop a semi truck. YOU cited a car length/10mph....which even though I feel is still overly conservative, I used that metric (did you read that?), which gives you ~115' at 80 mph....which.....your graph shows.....a 34% reduction in drag force.
So? What do YOU say? Is a 34% reduction in drag force, MEANINGFUL?
Their analysis said:
"...we were able to confirm our initial assumptions. Both drag and lift can be reduced by decreasing the following distance behind a truck. However, to get any noticeable reduction in energy expenditure, you would have to follow at an unsafe distance for a human driver’s reaction time. To gain any benefits in fuel economy, you would be putting yourself in danger of a collision if the truck came to a sudden stop"
What *I* said was:
Are you saying that (a 34% reduction) is not a meaningful reduction in drag?
...you didn't answer that.
As for that site's claim about safe following distances, I'm going to call BS on that. First, it's totally subjective w/no reference (distance) that I saw. They just say, "it's unsafe". BASED ON WHAT?! Nothing, that they provided. A Corvette will handily out stop a semi truck. YOU cited a car length/10mph....which even though I feel is still overly conservative, I used that metric (did you read that?), which gives you ~115' at 80 mph....which.....your graph shows.....a 34% reduction in drag force.
So? What do YOU say? Is a 34% reduction in drag force, MEANINGFUL?
So, take up your case with someone with a degree in aerodynamics in relation to vehicle traffic and see what they have to say about it. It should be enlightening.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
Why didn't you answer the question???? IS 34% MEANGINGFUL??
Really. That's what you're going to do now? What is "too close"? Earlier, I said 50'. I'm comfortable with that, but admit that is probably too close for most. After that, you said, "A vehicle length/10mph". So? What is "too close"? Seems like we need to clarify that....though I thought already we had. 
I'd suggest that you are now changing the circumstances. Now, we're talking about handicaps? If you have handicaps....well, that is totally different situation. You probably should follow anyone, at all. Or even drive, now? IDK. But citing handicaps doesn't really make a good case for the general population who can brake and steer, if necessary. If YOU can't do it...then you most certainly should not do it.
I'm enlightened. The data you provided, along with the criteria that you provided, proves that it matters, even at a safe distance. A study of your instant MPG while following (at a "safe distance") will provide evidence to you, in the real world -remember how I told you to "go try it"? Finally, a long road trip, with following at a "safe distance", will again, prove it in the real world. Enlightened? I'm OK, there. It is you the "pro", who needs to do some more home work. 
Racer
Joined: Jul 2016
Posts: 308
Likes: 79
From: Orange CALIFORNIA
The feather foot, 3.07 rear end gear, and skinny tires I think would yield significant, measurable MPG gains.
