Beginning next month, the Sanitation Department will institute a program intended to remove the graffiti from sanitation trucks. Any truck that finishes its assigned route before the end of the workers' shift will return to the sanitation lot, where supervisors will provide materials for workers to use in cleaning the trucks. Because the length of time it takes to complete different routes varies, trucks will no longer be assigned to a specific route but will be rotated among the routes. Therefore, workers should no longer leave personal items in the trucks, as they will not necessarily be using the same truck each day as they did in the past.According to the passage, which of the following is true of sanitation routes?