Data transmission time is crucial in real-time broadcast communication authentication protocols for vehicular networks. Prolonged transmission times can lead to communication delays, adversely impacting vehicle performance and protocol security. Utilizing computer simulations and tests proves challenging in imposing practical constraints on data transmission times and conducting security analyses for vehicular broadcast communication authentication protocols. Therefore, this paper proposes a real-time modeling and verification approach for vehicular broadcast communication source authentication. This method employs a model of the vehicular broadcast source authentication protocol to impose practical time constraints and management on data, addressing the issue of time verification in data transmission and enhancing the security of the vehicular Ethernet broadcast source authentication protocol. The modeling approach focuses on the real-time vehicular broadcast source authentication protocol, Gatekeeper, applying practical time constraints to different types of transmitted data. The analysis considers the necessary time security attributes within the protocol, establishing a timed automaton model based on the protocol's source authentication process. Finally, the real-time, confidentiality, and robustness of the vehicular broadcast source authentication protocol, Gatekeeper, were validated using the model-checking tool UPPAAL.