Actually, being in the truck's dead zone (drafting), you IMPROVE his mpg.
But, watch out for the rocks, road debris, etc. that will crack your windshield, or worse. Here, our freeways, especially the "truck" lane(s) are often not in good repair.
No - the slower you go, the better the mileage. See Tesla's graphs. The air resistence is proportionaly to the square (!) of the velocity.LTLFTcomposite wrote:Doesn't doing that reduce the fuel economy of the truck, resulting in greater CO2 emissions into the atmosphere?soareyes wrote:Frequently I will tuck in behind a semi in the slow lane and go 55-60 mph when I need to get max range.
What Gary said here - if you've ever watched Nascar (not that I recommend it!) you'll notice that on high speed ovals when two cars draft closely they can go faster than one car alone.garygid wrote:Actually, being in the truck's dead zone (drafting), you IMPROVE his mpg.
But, watch out for the rocks, road debris, etc. that will crack your windshield, or worse. Here, our freeways, especially the "truck" lane(s) are often not in good repair.
Actually by filling in this area with your car you may actually be improving his mileage. Best case you can slightly improve his mileage, but usually it will have zero effect on it.soareyes wrote:No, the dead air zone behind the truck is there whether I'm taking advantage of it or not. I have no effect on his mpg.LTLFTcomposite wrote:Doesn't doing that reduce the fuel economy of the truck, resulting in greater CO2 emissions into the atmosphere?soareyes wrote:Frequently I will tuck in behind a semi in the slow lane and go 55-60 mph when I need to get max range.
The other thing to watch out for is decapitation if the truck stops fast. All those air brakes can be surprisingly effective, and having your car sheared off at the belt line can be a real inconvenience.garygid wrote:Actually, being in the truck's dead zone (drafting), you IMPROVE his mpg.
But, watch out for the rocks, road debris, etc. that will crack your windshield, or worse. Here, our freeways, especially the "truck" lane(s) are often not in good repair.
Interestingly, using the mpg gauges in a Prius and Accord Hybrid and Civic Hybrid (assuming they are reasonably accurate), I've found that the long flatbed trailers provide a better increase to my mileage than the large box trailers, when following at about 1 second behind the truck which is close, but not too close. I was quite surprised by this result, and I have tried repeating this test several times in each of the cars, and it always seems to favor following an empty flatbed trailer.garygid wrote:Yes, the closely-following vehicle (usually too close to do safely on the public highway) essentially streamlines the leading vehicle, by filling in the "suction" area that occurs behind most "solo" vehicles.
With a large truck, the "suction" zone is a lot bigger, but to take maximum advantage of it, one might still need to follow dangerously close.
When following the truck a bit further back, the truck can still provide some wind-braking benefit to the following car, but the truck is less likely to experience any significant benefit.