Does down-shifting use more fuel?

always a good idea to leave your lights off at night as well--dont want to have that alternator working to hard---think of all that fuel used up

 

What about coasting downhill to a stop sign or red light?

 

Methinks the "truckers" you are talking to to get this advice are the type drive pickups with the little freezers in the back that sell that cheap, crappy "beef", or someone in a similar occupation. Or, you are talking to "truckers" that have zero experience and are in school, but, even then, most of those shouldn't be that stupid, as you seem to be.
Go troll somewhere else.

 

Caught a pic of Robert working on his "big rig". Disconnecting driveshaft & emergency brakes to save even more money.

 

I post this link because it explains engine braking and supports my argument.

http://en.wikipedia.org/wiki/Engine_braking

I'd like to add that reverse thrusters can be thought of as auxiliary brakes.
http://en.wikipedia.org/wiki/Thrust_reversal

 

Perfectly safe. Look! He's got a wheel blocked! (Jeeze, what an idiot)

 

Well, the troll keeps posting because, well, he's a troll. We keep posting because, well, we're truckers and we like to argue, I guess.