Partial link flow observability in the presence of initial sensors: Solution without path enumeration

Recently, a new methodology (“synergistic sensor location”) has been introduced to efficiently determine all link flows in a road network by using only a subset of the link flow measurements. In this paper, we generalize this previous work by solving the following problem: Suppose that one is only interested in a subset of the link flows, and that certain link flows are known a priori. At a minimum, what link flows are needed to be able to uniquely determine the desired link flows? An algorithm is presented that does not require the need for path enumeration.