$\%\%$Illustrate the complexities and considerations involved in the design and construction of an urban transportation network within a densely populated metropolitan area. In your response, address the challenges of integrating various modes of transportation $($e$.$g$.,$ roadways, railways, subways, and bicycle paths$)$ while ensuring the safety, efficiency, and sustainability of the system. Discuss the impact of topographical and geological conditions on the engineering decisions, the role of advanced materials and construction techniques in overcoming spatial constraints, and the necessity of accommodating future growth and technological advancements. Additionally, explain how the project can address environmental concerns, such as reducing pollution and managing stormwater runoff, and the importance of community involvement and stakeholder engagement throughout the planning and implementation stages. Lastly, consider the economic implications, including funding sources, cost$-$benefit analysis, and the potential for economic development spurred by improved transportation infrastructure.