in NY and other east coast cities, you not only have trucks that come round selling soft serve ice cream (and hard ices), but in many parts there are venders with hand trucks that either park at one spot (very desirable, and there are 'wars' for best corners, and in mid town, where things are very congested, you need permits!) and ones that have a route.

the carts are loaded on trucks at the end of the day.. most of vendors don't own the carts, but work them for a percentage of the day's take.