Do you save fuel by driving close behind other cars?

I know that one must maintain a safe distance b/w your car and the car in front. But while driving on the highway the other day, I wondered if it would help with the gas milage if I decrease the distance between my car and the car in front or if I drive behind a big truck. Would doing so help my car by reducing drag or would it not have much of an affect? What are your thoughts on this matter?

Yes it will improve mileage slightly. This is called Drafting, or drafting another vehicle.
When riding my motorcycle, I notice more of a difference when behind a semi trailer versus a full size pickup., even when at a safe distance...
Drafting on the highway is not very safe to do because your reducing the distance between you and the car in front of you .

No. In order for that to be effective you have to be so close it will seem like your vehicle is connected to the truck. Driving that close to a semi-truck is illegal in most if not all states. On top of that its extremely dangerous. If the trucker hits his brakes you won't have enough time to slam on yours. ie...you're dead. Is saving gas worth it?


It's called drafting and it's one of the tactics for hypermiling.
1.Close-in: Pulling into <> 1.0 seconds directly behind a semi-tractor trailer rig at speed. Results good as there is slightly less wind drag to break as well as being much safer than a Close-in.
3.Surf: Pulling in just behind and along side of semi-tractor trailer rig at speed attempting to reduce your own aerodynamic drag by riding in the broader wake the rig ahead and to the side of you has created. Results are minimal but better than driving naked into the wind.
4.Traffic Side: Traveling at a slower speed in the far right lane while traffic passing creates a bow wake effect across the entire highway/road in which you are traveling. Results are excellent the heavier the congestion is as long as there is some speed difference between you in the far right lanes and the traffic in the left lane(s) as you are receiving both the high fuel economy from the slower speeds as seen in the steady state speed tests above as well as receiving a lowered aerodynamic drag because of the wake helping to pull you along.