difference between slow down and slow up

slow down - ()
slow up - ()

slow down v. slow up

• Slow down is much, much more commonly used. You might slow down so someone can catch up to you, though.

• Where I live, people almost invariably say "slow down" rather than "slow up."

• Slow down is common in many circumstances in the Mid-Atlantic and Northeast U.S.
  It is used to ask someone to drive more slowly, walk more slowly, or speak more slowly.
  
  I remember hearing "slow up" more when I was a child, decades ago. It was usually
  said by a passenger to a driver, or by one kid on a bike to another.
  
  I'm surprised at the regional variations in AE. I shouldn't be, but I am.

What's the difference between slow up and slow down?

• Slow up means you are letting someone catch up with you. 
  
  Slow down means you are deducing speed for your own reasons

• slow up and slow down is the same to slow down but ppl say it different

• men slow down only for good-looking women.
  
  

slow down/ up?

(Could you please explain the difference between slow up and slow down?

A. Slow up/down! Don't run so fast!

B. Slow up/down, I don't understand what you're trying to say!

C. You should slow up/down your scooter a bit, otherwise we might get caught by the police.

Could you gimme some other examples?)

• slow down (sb/sth) or slow (sb/sth) down
  
  to become slower, or to make something or someone slower 
  Slow down, you two, I can't keep up with you.
  I was carrying some heavy bags so that slowed me down.
  It seems likely that the economy will slow down over the next twelve months.

• Just a personal note.
  I never use "slow up". It sounds very strange to my ear.
  To me it's "speed up" and "slow down".