As a cornerstone of cybersecurity, risk assessment facilitates identifying and grading potential threats. Despite several risk assessment methodologies tailored for the automotive industry, such as EVITA and HEAVEN, a substantial knowledge gap persists in the context of heavy-duty (HD) and medium-duty (MD) vehicles. This study seeks to bridge this gap by introducing a customized model derived from EVITA, specifically designed for HD/MD vehicles. This model enhances the existing EVITA framework by integrating updated severity and probability weights that reflect the unique applications of HD/MD vehicles. Additionally, the attack tree initially presented in EVITA, is augmented by incorporating Common Weakness Enumeration (CWE) and Common Vulnerabilities and Exposures (CVE) standards. This research presents a comprehensive risk assessment methodology for HD/MD vehicles by building upon the EVITA model. The revised severity and likelihood weighting and the integration of CWE and CVE result in a more precise and effective strategy for assessing and mitigating potential risks. The insights gained from this research contribute to the evolution of risk assessment techniques in the automotive industry, with a particular emphasis on heavy-duty and medium-duty vehicles.