  Vehicular networks promise features such as traffic management, route
scheduling, data exchange, entertainment, and much more. With any large-scale
technological integration comes the challenge of providing security. Blockchain
technology has been a popular choice of many studies for making the vehicular
network more secure. Its characteristics meet some of the essential security
requirements such as decentralization, transparency, tamper-proof nature, and
public audit. This study catalogues some of the notable efforts in this
direction over the last few years. We analyze around 75 blockchain-based
security schemes for vehicular networks from an application, security, and
blockchain perspective. The application perspective focuses on various
applications which use secure blockchain-based vehicular networks such as
transportation, parking, data sharing/ trading, and resource sharing. The
security perspective focuses on security requirements and attacks. The
blockchain perspective focuses on blockchain platforms, blockchain types, and
consensus mechanisms used in blockchain implementation. We also compile the
popular simulation tools used for simulating blockchain and for simulating
vehicular networks. Additionally, to give the readers a broader perspective of
the research area, we discuss the role of various state-of-the-art emerging
technologies in blockchain-based vehicular networks. Lastly, we summarize the
survey by listing out some common challenges and the future research directions
in this field.
