"Develop a comprehensive roadmap for implementing accessible public transportation systems in metropolitan areas, focusing on strategies for integrating accessible options into existing infrastructure. Address the challenges of urban planning and provide in-depth, real-world examples and case studies.** Ensure the roadmap covers:** ## 1. Assessing current transportation infrastructure and identifying areas for accessibility improvement. ## 2. Strategies for overcoming common obstacles, such as funding constraints and community resistance. ## 3. Leveraging innovative technologies to enhance accessibility and efficiency. ## 4. Case studies of successful accessible public transportation systems in metropolitan areas. ## 5. Recommendations for sustainable, equitable solutions that balance the needs of diverse stakeholders. ## 6. A step-by-step implementation plan, including timelines, milestones, and key performance indicators. ## 7. Considerations for ensuring the long-term maintenance and upgrade of accessible transportation systems. Provide detailed, actionable guidance tailored to advanced urban planners seeking to enhance the inclusivity and efficiency of their public transportation networks."