The automobile sector is all set to be completely transformed by autonomous cars, which are attracting a lot of interest from both academic and business enterprises. The interconnectivity of separate elements in autonomous vehicle (AV) systems, nevertheless, introduces weaknesses into the network in general. Conventional security techniques may not have been able to resolve these problems. A potent instrument that can help increase the trust and dependability in these kinds of networks is blockchain technology. The two main blockchain ecosystems are Ethereum and bitcoin. Research on how blockchain improves both security and other elements of AV systems was presented in this article. It was demonstrated how blockchain technology assists with a variety of AV-related use cases, including shared storage, improved security, enhanced vehicle functionality, and enhancement of connected sectors. Both the security and vehicle functionality were improved using nature-inspired heuristic algorithm referred to as elephant herd optimization (EHO). The optimization of parameters helped in enhancing the vehicle functionality as well as security in a more efficient manner. Results indicated that, compared with existing methods, the proposed EHO-based blockchain achieved less delay, lower reputation score, higher precision, and lower miss rate with percentages of 83.33%, 56.52%, 38.46%, and 22.22%, respectively. This offers possibilities for development in the field of AV, which may be attained by integrating blockchain technology into intelligent transport systems (ITS) or specific vehicular units.