Are you playing on a new map that doesn't have pedestrian or vehicle paths yet?
Now you can spawn 8 walkers around Carl! Press "C" and "D" together to make them appear. Pedestrians will be the same as you can find in the area in which the player is currently located - for example, in the forest you can create villagers, and on Grove Street - the poor. You can create pedestrians an unlimited number of times, therefore, no one interferes with creating a huge crowd :)
The script works only when CJ is not in the car and not in the water.