Pylons
After the ANWB vehicle is placed in the specific ANWB scenario (see the ANWB scenario Laser Pointer for more details on placing it), you can take the Pylons out of the truck and place them on the highway to stop the cars from using a lane. How to use
When the ANWB car is spawned, you can get the Pylons by opening the back. You do this by reaching for the handle, which will highlight it, and pressing the trigger on your controller. Then, using the same technique you used for opening the doors, you can pick up the Pylon stack. In a similar fashion to picking up the Pylon stack, you can also use your other hand/controller to get a single Pylon from the stack.
With the single Pylon in hand, you can drop it anywhere you want by pressing the top button of the controller you are holding the Pylon with. If you put it down on a lane, it will stop the cars from driving in that lane.