Effect of Video Detection System Layout under Covering and Differentiating Route Flow Principles

Video detection system (VDS) sensors play an important role in monitoring traffic flows. Because of limited numbers of camera installations, there is a dilemma in positioning camera sensors between the system’s coverage and its capability to differentiate flows on the network. Existing studies have mainly focused on the observability, evaluation, and estimation of traffic flows in the network sensors location problem (NSLP) field. The effect of covering and differentiating route flows for VDS’s layout has not been fully investigated. This study explored three sensor positioning principles: covering first, differentiating first, and weighted. Corresponding greedy algorithms were developed for each of the three principles. The algorithms using the three principles were tested on a commonly used (by previous studies) medium-sized network and a large-scale real-world network. The covering first principle was found to be more sensitive to the coverage rate of networks. To achieve full coverage, VDS sensors need to be installed on a minimum of 10% and 15.3% of links for medium- and large-scale networks, respectively. The differentiating first and weighted principles outperformed the covering first principle in the large network because they extracted an extra 19% of unique route flows. Therefore, the covering first principle is recommended for deployment of a VDS on small- and medium-sized networks because of its greater capacity to cover route flows and differentiating capacity similar to that of the other principles. It is practical for large-scale networks to utilize the differentiating first and weighted principles to locate VDS sensors because of their greater capacity to extract unique route flows and similar coverage.