Yeah this is what I'm trying to figure out aswell.
It seems that this mod stops cars by freezing them in place, and if the driver somehow gets out of the vehicle while they're frozen in place, they cannot be unfrozen regardless of them getting back, you trying to move the vehicle (it's still stuck in place) or such. This mod needs a failsafe/reset on a stopped car when there's no driver, so it's compatible with StopThePed, since so far STP seems to be the best tool for creating a DUI checkpoint so far. To my knowledge there are no mods which allow you to pull up the traffic stop menu while being on foot, which is sad because that feature combined with this mod would make a great DUI checkpoint.
So far, this mod is great for redirecting traffic, but unfortunately isn't practical for LSPD:FR checkpoints, since there are no compatible mods which allow any pullover interaction menu functionality without going through the whole hassle of pulling someone over in a vehicle.