Cooperative Intelligent Transportation Systems (C-ITS) enhance road safety applications by allowing vehicles to share important data with low delay. In Europe, the frequency range of 5875-5935 MHz is designated for safety-oriented ITS applications. Different wireless technologies have been proposed to support ITS applications in this band, with a focus on ITS- G5 and C-V2X. We have shown that a 5G private network can be operated in this unlicensed band using a Listen-Before-Talk (LBT) mechanism for coexistence with other technologies. In this paper, we characterize its ability to support C-ITS applications while coexisting with ITS-G5. This paper demonstrates for the first time the practical feasibility of coexistence between ITS-G5 and 5G New Radio-Unlicensed (5G NR-U) in the 5.9 GHz C-ITS band in asynchronous mode through experimental characteriza- tion of the mutual impact of the two technologies. Our results show that even under a maximum 8 Mbit/s NR-U uplink load and the concurrent transmission of 509-byte MAPEM messages at 10 Hz over ITS-G5, corresponding to a combined channel busy ratio (CBR) of 26%, ITS-G5 latency increases by less than 0.7 ms while maintaining a PDR above 96.7%. These findings confirm that ITS-G5 and 5G NR-U can coexist with negligible impact on safety-critical communications