So when you are not drafting, you're getting 48 MPG at 60-65 mph? That doesn't make sense because my 03 Prius is in the 54-52 MPG range at those speeds. Your HCH should be getting at least as good without drafting.

Perhaps but I prefer variety, XM radio. As for drafting being stress free, you should try it with my wife in the right seat.

What speeds?

Speeds?

The reason I'm asking about the speed for any given MPG is to find out if your drafting really is giving a 25% improvement. What if it is only 10%? What if it is only 5%?

With an automated, distance following system like the "smart cruise control" it might make sense. If there were a telemetry and/or video link between the lead driver, truck or otherwise, and the following cars to handle synchronous braking and steering, it would make sense. But to drive blind at 65 mph without coordination with the lead driver, that is not wise. Heck, even this would be a better solution:


Bob Wilson

 

All very good information. It has been diffficult to find a large truck using cruise control at the speed I would like to go. The Honda has a sweetspot just under 60 mph that yields 52 to 56 mpg when th cruise control is engaged. I continue to learn more about high mileage hybrid driving.
Mike

 

I spend most of my daily commute at 55-60 using CC. For those commutes when trucks are in front of me blocking wind most of the way, I would estimate it yields up to about 10% improvement in FE (~65 vs ~60mpg) versus driving "naked" into the wind. This is based on about 150 daily round trips I have made with my HCH2.

I suppose that while you are right behind the truck, the benefits might be higher than 10%, but I would not reccomend chasing/following close in - unsafe and may actually waste fuel trying to catch a truck.

Trucks tend to speed, but often I can find one going only 5mph over their (reduced) speed limit - those I might stay behind.

 

I tried "drafting" in the Passat for the first time today. I followed a school bus from about 3-4 car lengths, and perhaps it was the placebo effect or a slightly downhill stretch, but there seemed to be less turbulence and the instant consumption increased from MPG in the 30s to the 40s. Obviously it required a lot more concentration than dawdling along in the right lane at 55 miles per hour, but it quickly brought up the average.

I ended up getting 30.5 MPG over 28.4 miles freeway, 7.3 miles city, medium traffic. If I drove according to the original EPA estimates (which itself is hypermiling) of 21/30, I would have gotten 28.155 MPG.

I wonder how much better I would fare if I still had the OEM low-grip 195s instead of these 215s with heavier alloys. It was cold today, too, and the engine took forever the warm up. I was averaging ~14 MPG the first mile or so. Wonder if turning on the A/C to warm the engine sooner would have helped...

Average speed was low-30-something mph. Forgot. Too bad trip computer 1 resets after the car is off for two hours.

 

I had some truck get really POd because I was drafting him from 150 YARDS back. He didn't want me there for whatever reason, so I stole another draft behind a truck that passed him. He gave me the highbeams and everything and he was about 25 yards behind another truck. I can see if I was not visible in his mirrors but I was far enough back that I was barely gaining anything from the draft. Maybe he wanted me closer?

 

Being an assh*le is an equal opportunity employer. It is just the luck of the draw and nothing else. If it irritates you, it is probably time to take a potty break, enjoy a beverage and keep on, keepin' on.

Bob Wilson

 

My take, the air pattern behind a truck is like a vortex of air, one from the top and one from each side, the vortex spin in different directions (eg, the top vortex spins downward and then up, the right side spins clockwise the left side counterclockwise). If you are lucky enough to be within the range of all 3 vortices, your car will be pulled by the air flow. The beginning of the post the writer stated that turbulence existed that’s because the top vortex was breaking further back and the left and right vortices were pounding the vehicle. Also the car is more stable front to back (longer wheelbase) from side to side the shorter distance between the wheels makes the effects more noticeable.
I hope that my explanation or understanding is correct; I find that drafting is a certain fuel economy booster.

 

For me, trucks are a 'pace car' that allows me to cruise at an efficient speed and not have to deal with the impatient who want to flash lights and behave badly. So I follow the trucks at a safe, no-ticket distance and have a happy. Being in the right speed zone is quite enough.

As for drafting, if the car is equipped with a robot drive system to maintain distances and a video link that shows what the truck driver is approaching, I'm with you 100%. Otherwise, truck drafting is not worth it.

We used to say in aviation that the FAR regulations were written in spilled blood. IMHO, regulations against drafting use the same ink. It isn't that it can't be done, just the odds are against it.

Bob Wilson

 

Are you a fellow pilot?

 

No longer current. I had to choose between the wife and plane about 35 years ago . . . I still have the wife.

Bob Wilson