In vehicular ad-hoc networks (VANETs), real-time message exchange between vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communication is essential for transportation efficiency and passenger safety. Ensuring message security and timeliness relies on an effective privacy-preserving authentication mechanism. A certificateless multi-receiver signcryption scheme enables a sender to transmit messages to multiple recipients simultaneously while avoiding key escrow issues. However, existing schemes require secure channels for key extraction, and cannot allow the Key Generation Center (KGC) to verify pseudonym legitimacy. To address these issues, this paper proposes an anonymous certificateless multi-receiver signcryption scheme for vehicular networks that supports signature aggregation and eliminates the need for secure channels. Security analysis demonstrates that the scheme achieves ciphertext unforgeability and confidentiality under the ECDL and CDH assumptions. Compared to existing schemes, it significantly reduces the computational cost of signcryption and unsigncryption.