  Connected vehicle (CV) technology enables data exchange between vehicles and
transportation infrastructure and therefore has great potentials to improve
current traffic signal control systems. However, this connectivity might also
bring cyber security concerns. As the first step in investigating the cyber
security of CV-based traffic signal control (CV-TSC) systems, potential cyber
threats need to be identified and corresponding impact needs to be evaluated.
In this paper, we aim to evaluate the impact of cyber attacks on CV-TSC systems
by considering a realistic attack scenario in which the control logic of a
CV-TSC system is unavailable to attackers. Our threat model presumes that an
attacker may learn the control logic using a surrogate model. Based on the
surrogate model, the attacker may launch falsified data attacks to influence
signal control decisions. In the case study, we realistically evaluate the
impact of falsified data attacks on an existing CV-TSC system (i.e., I-SIG).
