Smart cities use advanced infrastructure and technology to improve the quality of life for their citizens. Collaborative services in smart cities are making the smart city ecosystem more reliable. These services are required to enhance the operation of interoperable systems, such as smart transportation services that share their data with smart safety services to execute emergency response, surveillance, and criminal prevention measures. However, an important issue in this ecosystem is data security, which involves the protection of sensitive data exchange during the interoperability of heterogeneous smart services. Researchers have addressed these issues through blockchain integration and the implementation of smart contracts, where collaborative applications can enhance both the efficiency and security of the smart city ecosystem. Despite these facts, complexity is an issue in smart contracts since complex coding associated with their deployment might influence the performance and scalability of collaborative applications in interconnected systems. These challenges underscore the need to optimize smart contract code to ensure efficient and scalable solutions in the smart city ecosystem. In this article, we propose a new framework that integrates generative AI with blockchain in order to eliminate the limitations of smart contracts. We make use of models such as GPT-2, GPT-3, and GPT4, which natively can write and optimize code in an efficient manner and support multiple programming languages, including Python 3.12.x and Solidity. To validate our proposed framework, we integrate these models with already existing frameworks for collaborative smart services to optimize smart contract code, reducing resource-intensive processes while maintaining security and efficiency. Our findings demonstrate that GPT-4-based optimized smart contracts outperform other optimized and non-optimized approaches. This integration reduces smart contract execution overhead, enhances security, and improves scalability, paving the way for a more robust and efficient smart contract ecosystem in smart city applications.

Intelligent transport plays a pivotal role in smart cities by optimizing traffic flow, reducing congestion, and minimizing environmental impact. Through real-time data analysis and smart routing, it enhances transportation efficiency while promoting sustainable urban development and improving the quality of life for residents. To improve the security of digital transportation systems, researchers are investigating blockchain-based solutions. The decentralized and immutable nature of blockchain can protect transportation data from unauthorized access. However, the consensus mechanism of blockchain platforms may hinder the responsiveness of intelligent transportation systems. Processing time-sensitive data could be delayed if multiple nodes are required to reach a consensus. To address this problem, a novel consensus mechanism utilizing smart contracts and the blockchain’s underlying consensus protocol has been proposed. This strategy seeks to improve the responsiveness of smart transport mechanisms by combining the strengths of smart contracts and the consensus protocol of a blockchain. It has the potential to optimize real-time data processing and boost the overall performance of intelligent transportation systems.