Create my own police Roadblock

[BOSSSSS-GG 80]

Hello, I want something that makes to create a roadblock, but I am failed in it, so I am asking your help, please help.

 

 

 

I created a code which create a 5 peds and 2 cars but they spawn only one time after reloading script it again works. so what to do for creating roadblock like Rockstar did for bridges roadblock whenever we visit the bridges the game spawns police with their cars.

 

 

 

Please help . GTA IV