This is very easy and done in ~5 minutes.
Race from start of highway near airgield with a supercar at full speed to the end.
Then you should have over 50% of speed skills with no effort.
Drive same way back, and challenge is done.
Use achievement tracker to see the progress fly upwards while driving .
Any speed skill you get on the way counts. Daredevil, Great speed, awesome speed etc.
You get these skills frequently just by driving full speed.