This is a rendering of what the Purple Line station would look like in Riverdale Park. Both quality of life and the real estate market in the D.C. area depend greatly on reliable regional mobility. (Maryland Transit Administration)

Both the quality of life and the real estate market in the Washington area depend greatly on sustaining and enhancing regional mobility. But ensuring — and paying for — reliable regional mobility has become increasingly challenging, as evidenced by the multitude of vexing transportation problems reported in recent weeks.

Conceived decades ago as a trolley line along the Georgetown Branch, the Purple Line is to run between Bethesda in Montgomery County and New Carrollton in Prince George’s County. It would be the first segment of what some day couldbecome a light-rail transit line circling the Washington suburbs and circumferentially linking Metro’s radial subway lines.

But financially, the Purple Line is solely a Maryland project. And although Maryland Gov. Larry Hogan (R) recently decided to support the project, he proposed much less state funding than expected.

Therefore, additional funding must come from the two counties and the federal government. The project might even be partly financed, built and run by a private, for-profit operator. In any case, despite the governor’s affirmative decision, as of now the financial feasibility of the Purple Line is not assured.

Meanwhile, in the District, the long-delayed streetcar line along H Street NE continues to fail operational performance and technical safety tests, despite years of design and millions of dollars expended by the District to construct the line and acquire new streetcars. This seems to be a story of “The Little Engine that Could Not.”

Metro’s chronic subway maintenance and repair issues — rail defects, electrical mishaps, elevator outages, escalator repairs — seem to be in the news on a daily basis. Although partly attributable to management shortcomings, the primary cause is chronically insufficient revenue and working capital. This reflects the conceptual flaw inherent in Metro’s structure and governance: its financial and policy dependency on the many, politically disparate jurisdictions it serves.

Clearly, lack of money within autonomous county and city jurisdictions, as well as at the state level, impedes timely repairs, maintenance, reconstruction and new construction not only of transit but also of the region’s roads and bridges.

All these difficulties are emblematic of one overarching, systemic reality. Because of political and jurisdictional fragmentation, no region­wide transportation entity exists. Instead, the region is a patchwork quilt of diverse state, county and city transportation departments whose budgets and staffs depend on elected officials with often parochial, short-term views.

Problems plague rails, roads and bridges because the District, Maryland and Virginia, and the states’ counties and municipalities, are politically and fiscally autonomous. Each acts mostly independently. And each jurisdiction separately experiences economic resource shortages preventing it from adequately monitoring, repairing and maintaining transportation infrastructure within its governmental boundaries.

Thus, mobility in metropolitan Washington suffers from the lack of an integrated, region­wide authority capable of comprehensively planning, financing, implementing and maintaining the region’s increasingly interconnected and interdependent transportation systems and networks.

This metropolitan-scale systemic deficiency adversely affects not only long-term capital investment in transportation infrastructure but also annual operating budgets essential for sustaining the performance and safety of the region’s existing infrastructure.

Integrated transportation and enhanced mobility, while a local need, have become an ever more vital regional necessity because mobility needs and travel behavior are increasingly regional, not just local.

Tens of thousands of area residents commute to work, go shopping, attend sports events, call on friends, or visit museums and public parks by crossing jurisdictional boundaries. In many areas, access to and use of transit measurably lessen traffic congestion, a benefit for drivers who never use transit.

Yet persuading voters to think and act regionally is very difficult. An Arlington resident understandably questions why she should care about or help finance a transportation project in the District, Prince George’s or Montgomery or even neighboring Fairfax County. A Loudoun County taxpayer who never rides the subway is likely to oppose being taxed to pay for construction of a subway line anywhere, even to Dulles International Airport.

Likewise, most suburban Virginia and Maryland voters balk if asked to help pay for transportation improvements in the District. And many D.C. voters would feel the same about transportation projects in the Virginia and Maryland suburbs.

Overcoming politically parochial resistance to region­wide transportation planning and financing across boundaries will be a hard sell. Yet in the long run, people living and working in metropolitan Washington need to think of themselves as metropolitan Washingtonians and not just as residents of D.C., Virginia or Maryland.

Only then will they understand that financially supporting projects miles away ultimately benefits them.

Roger K. Lewis is a practicing architect, a professor emeritus of architecture at the University of Maryland and a regular guest commentator on WAMU’s “The Kojo Nnamdi Show.”