Cooperative automated driving is a promising technology to improve road safety, fuel consumption, and traffic throughput without the need to expand the current infrastructure. To accelerate the developments in cooperative driving toward deployment in realistic traffic, the second grand cooperative driving challenge (GCDC) took place in Helmond, The Netherlands, in 2016. The aim of this implementation oriented challenge is to validate the practical feasibility and benefits of cooperative automated driving in the context of several advanced traffic scenarios, including cooperative merging on a highway and cooperative intersection crossing. Since all scenarios require road participants to cooperate, an interaction protocol was provided for each scenario. Except for this pre-defined interaction protocol, each team had full flexibility in developing the cooperative automated vehicle system. As such, one of the main difficulties of the challenge was to ensure interoperability despite the fact that each road participant might use different vehicle types and vehicle control systems that have been developed independently. In this paper, we provide an overview of the ATeam's implementation of the cooperative automated driving system for the cooperative merging on a highway and cooperative intersection crossing scenarios. This overview addresses the hardware architecture used during GCDC and, the design and integration of the required software layers. This paper also addresses practical issues that need to be taken into account when developing a cooperative automated driving system such as the limited capabilities of sensors and imperfections induced by the packet-based communication. Moreover, we present experimental results that were obtained during the challenge.