Support for Car Talk is provided by:

Discussion Rules

Login
Submit a Car Question

Drafting Behind a Semi

When a car drafts behind a semi truck, just who is saving who gas? That was Tim's question, on this week's Car Talk. Tim, a semi driver himself, thinks the drafters are benefiting at his expense -- after all, someone's gotta create the energy the drafters are getting, right? "Au contraire, Piston Pop", say Tim's kids -- they think it doesn't hurt his mileage at all.

A steak dinner hangs in the balance.

Who's right?

Ray posited that -- ready for this? -- a car drafting behind a semi actually saves both vehicles some fuel. No kidding!

What do you think? Could Ray be right, despite all those years of flunking classes at MIT?

Share your thoughts right here. And thanks!

by: BarryNNJ 05/03/2008 3:42:10 PM
Top 250 Contributor
Re: Drafting Behind a Semi
I have this to say about that.
by: henrye 05/03/2008 4:53:18 PM
Re: Re: Drafting Behind a Semi
The Feds using our hard earned tax dollars have throughly studied truck/trailer dynamics with an eye towards decreasing fuel usage and recommended that truck trailers be required to have a "boat tail" on rear end to improve the aerodynamics. http://www...oveme.html
by: Z69105 05/03/2008 6:20:59 PM
Top 250 Contributor
Re: Drafting Behind a Semi
Funny you should mention this. I recall "drafting" a semi at 75mph between Staunton, VA and Washington, DC.

Dunno about fuel economy, but it cut wind noise significantly.
by: jtsanders 05/05/2008 8:52:23 PM
Top 20 Contributor
Re: Re: Drafting Behind a Semi
I'm surprised (happily) that you lived through the event. Do you engage in kamikaze driving often? :(
by: Troubleshooter 05/10/2008 2:28:41 AM
Top 250 Contributor
Re: Drafting Behind a Semi
DON'T DO THIS!!!!

Tailgating is one of the biggest causes of accidents.

The tiny amount you save in fuel will be lost when you have to pay for the damage to both vehicles.

Mythbusters proved it works, but the distance it works at is so short as to make it very dangerous.

NASCAR is also known for crashes, and most of them are caused by getting too close.

RSS
Powered by Public Interactive