In San Francisco at least, food trucks and carts pay the city a fairly hefty fee to operate and park. It would be difficult to justify a demand system since da

In San Francisco at least, food trucks and carts pay the city a fairly hefty fee to operate and park. It would be difficult to justify a demand system since day passes for parking meters are sold for things like moving trucks well ahead of time (how do you price something on a random Tuesday two weeks ahead of time?). However, the day parking passes are quite expensive (~$200 for 4 spots all day), so I'm not sure that even at peak demand, the city would make more than that in meter fees.