First thing,are you the house owner and the space part of your freehold?
If yes,then you can do as you like.If no,then you have to be carefull.
As to fixing,if it's tarmac I'm not sure you'll have much to bolt to,if the tarmac is just layed over hardcore it'll be like trying to fix a bolt into the beach.
A better way would be cut a neat square of tarmac out,dig a hole and fix studs in with postcrete.You just pour water in hole then tip the postcrete in and it goes off in 10 minutes.
Get a bit of ply or chipboard and drill holes in to match your post.Mark ground where edge of wood should be and screw nuts onto studs at height they will end up.Pour in postcrete,drop board over hole and push studs through quickly.
When it goes off,it may be less than 10 minutes so don't hang about,you remove nuts and fix post.
Postcrete about £5 a bag,studding from Screwfix.
Looking at the post in link above,you'd need a hole anyway but I'd use a small bag of concrete mix to give you more time,on the plus side you've got the post base as a guide for the studs.