Food trucks that look like they are wandering are usually following a fixed schedule built around when and where crowds concentrate. The route is an economic decision made before any cooking happens.
Revenue arrives in short bursts
A truck has one service window, a small cooking surface and a limited number of hands, which caps how many orders it can produce per hour.
That ceiling means the difference between a good day and a bad one is whether the crowd shows up during the hours the truck is capable of serving them.
Sitting somewhere quiet costs the same in fuel, staff and prepared food as sitting somewhere busy, so an empty hour is a loss rather than a break.
Office districts empty out completely
A business district generates dense demand within a narrow lunch window and then has almost no foot traffic once the working day ends.
Staying past that window means serving nobody in a place with nowhere else to draw customers from, since the residents are elsewhere.
The truck therefore relocates to wherever the next concentration forms, which is usually a residential area, a nightlife strip or an event.
Prep is done before the wheels move
A truck kitchen is too small to prepare components during service, so almost everything is portioned, marinated and part-cooked in advance.
That preparation has to be sized to the expected day, since unsold prepared food generally cannot be carried forward and unprepared food cannot be sold.
Forecasting the route accurately is therefore a food-cost decision as much as a sales one, and consistent schedules exist largely to make the forecast possible.
Regulars are built through predictability
Trucks post their location because customers cannot find them otherwise, and a customer who cannot find you twice stops looking.
A repeating weekly pattern lets people plan around it, which converts a novelty purchase into a habit and smooths out demand.
This is why many successful trucks look less mobile over time, appearing in the same three or four places on the same days for years.
The rules constrain the map
Where a truck may park, for how long and how close to a fixed restaurant is regulated, and the specifics differ considerably between cities and change over time.
Private lots, breweries and office campuses sidestep some of that by inviting trucks onto property where public parking rules do not apply.
Those arrangements now shape routes as much as demand does, which is why the busiest corner in a city often has no truck on it at all.