Connected and autonomous/automated vehicle (CAV) technologies are shaping the design and the new developments in the automotive industry and, in a wider perspective, in the mobility sector as well. Despite the recent advances and on-going developments, and the enthusiasm around autonomous mobility systems, real-world testing of CAVs is a crucial element to allow the next generation of intelligent vehicles to come to our daily-life. The importance of realistic testing is recognized by academia, industry, public sector and stakeholders, and is reflected in all projects involving pilots and advanced prototyping. AUTOCITS* is one of the projects where CAVs and interoperability tests have been conducted. This paper concentrates on the assessment and performance evaluation of tests carried out during the AUTOCITS's Lisbon Pilot, in realworld conditions, involving CAVs and C-ITS technologies. New specific quantitative indicators (key performance indicators - KPls) are proposed to back the assessment and evaluation criteria presented in this work. The KPIs' expressions are provided, which demonstrated to be very difficult to find in the literature. Results are reported and discussed according to the scenarios and field-data recorded during the Pilot.