# Enhanced Scalability and Security in Blockchain-Based Transportation Systems for Mass Gatherings
## 3 Methodology  
This section presents a methodology to tackle the scalability and security issues that may occur when implementing blockchain solutions for mass event transportation systems [6,7]. The framework in Figure 4 incorporates four key components: data pre-processing, integration with blockchain, scalability, and cryptographic security to address large volumes of transactions and ensure data security.  
The pre-processing of transportation system data involves collecting and normalizing data, such as traffic, vehicle positions, and passenger counts, which can be integrated into blockchain technology for rapid processing [2,4]. Tolls and lane management utilize blockchain technology, which decentralizes records and enhances security and integrity through the use of private blockchains and smart contracts. To achieve fault tolerance, nodes must be decentralized among transportation authorities and third-party providers. Practical Byzantine Fault Tolerance (PBFT) consensus is used to prevent fraud in the use of cryptocurrencies, e.g., [6].  
\begin{table}
\begin{tabular}{c c c c c c} \hline
**Refer-** & **Services** & **Contributions** & **Methodology** & **Limitations** & **Innovation in Our Study** \\ \hline
[13] & Blockchain & \begin{tabular}{c} Securing and \\ tracking \\ healthcare data \\ \end{tabular} & \begin{tabular}{c} Developed models \\ for healthcare data \\ security and \\ traceability. \\ \end{tabular} & \
\begin{tabular}{c} Focused only on \\ healthcare, not \\ transport systems. \\ \end{tabular} &
\begin{tabular}{c} Our study integrates \\ secure patient data \\ management and tracking \\ models from healthcare \\ into mass transportation, \\ ensuring traceability of \\ services during mass \\ gatherings. \\ \end{tabular} \\ \hline
[14] & Smart & Automating & Developed smart & It primarily & Our study combines smart & \\ contracts in & transportation & \begin{tabular}{c} Developed smart \\ contract-based \\ solutions. \\ \end{tabular} & \
\begin{tabular}{c} It primarily \\ focuses on smart \\ contracts, but does \\ not address \\ scalability. \\ \end{tabular} &
\begin{tabular}{c} Our study combines smart \\ contracts with scalability \\ solutions for entire \\ transportation systems. \\ \end{tabular} \\ \hline
[16] & Blockchain & \begin{tabular}{c} Blockchain for \\ Hajj \\ operations \\ \end{tabular} & \begin{tabular}{c} Blockchain for \\ Hajj \\ transportation \\ improvement. \\ \end{tabular} & \begin{tabular}{c} Case study \\ approach for Hajj \\ operations. \\ \end{tabular} & \
\begin{tabular}{c} Limited to a case \\ study, lacks \\ generalizability. \\ \end{tabular} &
\begin{tabular}{c} Our study proposes a \\ comprehensive blockchain \\ solution that integrates \\ multiple services for Hajj \\ transportation. \\ \end{tabular} \\ \hline \end{tabular}
\end{table}
Table 1: Cont.  
Furthermore, congestion solutions are provided using Layer 2 techniques, such as State Channels and Rollups, to reduce the load on the blockchain. Off-chain transactions are facilitated through State Channels, with only the initial and final states being recorded. Conversely, Rollups are used to batch transactions, sending compressed proofs to the main chain [7]. Transactions in ZK-Rollups are verified through AES-256 encryption, PKI, and ZKP, which are used for security and privacy [8; 9]. At the same time, optimistic Rollups rely on a chain of transactions being valid unless challenged. This also enhances scalability while allowing for the ability to adapt to technological changes.