“they could have just pulled the vans off the road”
The wheels were popped and/or removed for a reason — so they were immobile.
A D-8 Cat with a 12 foot blade will make them mobile again. The flatbeds have winches with 1/2 to 3/4 cables. Hook them to the rear axle or front suspension open the throttle they will become mobile again.
Nice if they can find out whose vans they were or who rented them.
They pulled them off without the wheels anyway.