The technology exists, but it hasn't been used in this game in a long time...
Short answer: not possible.
Roadblocks are powerful and can only be placed once during each race, they don't respawn either. Not possible unless someone digs into the game's code.
The hidden dialogues don't make much sense to add because the reset feature is available to the player and the permission is useless since you, as the leader of the cop team, always have permission to make the wingmen deploy spikes/roadblocks. These are intended to help the human racers rather than be used by the human cop.