Then you will need to set a speed number to check instead of every tick.
You use global variables for that
Global Variable SPEEDCHECK =0
Every Tick Set SPEEDCHECK to Player Speed
On SPEEDCHECK = 25 Add 25 to Player Score Set SPEEDCHECK to 1001
On SPEEDCHECK = 50 Add 50 to Player Score Set SPEEDCHECK to 1001
On SPEEDCHECK =0 Subtract 100 from Player Score Set SPEEDCHECK to 1001
It all depends on how you want your game played but those are the events and you just have to set them how you want your game played.
You have to set SPEEDCHECK to a number you are not checking after each speed check event or it will keep adding to the score as long as the player maintains that speed.