A widely-researched C-ITS service is the Green Light Optimal Speed Advisory (GLOSA) a.k.a. the Eco-Cooperative Adaptive Cruise Control (Eco-CACC), provided to connected vehicles near signalized intersections. Two primary objectives were aimed in this study: 1) Investigate the driver response behavior to GLOSA messages in a real-world naturalistic driving environment. 2) Incorporate the driver response behavior in an integrated simulation environment to extend the results to generic situations and to scale up the assessed impacts.