Vehicle platform development is among the most complex and capital-intensive undertakings in manufacturing, typically spanning 36 to 48 months from concept to start of production (SOP) and involving engineering expenditure of USD 1 billion to more than USD 6 billion. This paper examines the application of the Critical Path Method (CPM) to new vehicle platform development, using three illustrative but industry-representative case studies: a B-segment passenger car (Project Alpha), a C-segment SUV (Project Beta), and a D-segment battery electric vehicle (Project Gamma). Simulated schedule data, calibrated to published automotive benchmarks and APQP timelines, were analysed using forward/backward pass CPM calculations, float distributions, and Earned Value Analysis (Schedule Performance Index and Schedule Variance). The study finds that powertrain integration, regulatory homologation, and supplier PPAP (Production Part Approval Process) validation are consistently the dominant critical-path drivers across all three platforms, and that electric vehicle development introduces materially greater schedule complexity and variance, driven by battery system integration, battery management system (BMS) software validation, and evolving ADAS certification requirements. Schedule compression through crashing recovered two to four weeks of critical-path time at cost premiums of 12-35% of affected activity budgets, while fast-tracking carried substantially higher rework risk. The paper recommends that automotive OEMs adopt hybrid CPM-Design Structure Matrix (DSM) scheduling frameworks, institutionalise Monte Carlo schedule simulation, and develop dedicated scheduling competencies for electric vehicle and software-defined vehicle programmes. The findings extend the applicability of a decades-old scheduling technique to the contemporary electrification context and offer practical guidance for automotive programme managers and Tier-1 suppliers.