NO ONE knows the contours of post-pandemic working life, but it’s a fair bet that the world will not be so radically remade that traffic disappears and highways run free and clear at rush hour. That’s particularly true in the Washington metropolitan area, whose pre-pandemic daily congestion was among the worst in the nation. Suburban sprawl and booming population growth will remain, and bridges and roads long regarded as obsolete or inadequate are unlikely suddenly to suffice.

That’s the most basic rationale for Maryland’s ongoing effort to rebuild and widen the nearly 60-year-old American Legion Bridge over the Potomac, and connect it to new high-occupancy toll lanes to widen the adjoining portion of the Beltway and Interstate 270 north to Frederick. There is no politically plausible scenario whereby the state on its own can finance such an undertaking, which would cost billions of dollars. Hence Gov. Larry Hogan’s (R) brash determination in pressing ahead with a partnership in which the state grants a private-sector entity the right to design, build and operate the new infrastructure for decades, in return for which the company will keep most of the toll revenue.

The governor’s vision took a critical first step toward becoming reality this week when the state announced it had chosen an experienced toll operator, the Australian conglomerate Transurban, to handle the pre-construction design and development for the widened highways. Transurban is already successfully building out 65 miles of new HOT lanes on I-95, I-395 and the Beltway in Northern Virginia, which would connect over the rebuilt bridge with the Beltway in Maryland.

It makes sense for Marylanders to support this undertaking — with eyes wide-open. No similarly massive construction project can be painless, and this one would not be, either. Expect legal challenges on environmental and other grounds, local political opposition owing to the impact on homes and businesses, and construction glitches, among other obstacles.

To minimize those problems, the state plan, if approved, would set a roughly 18-month lead time for itself and Transurban to design a project that anticipates and addresses foreseeable technical and political problems before finalizing the details and the price. That is the lesson state officials have taken from the cautionary tale of Maryland’s $5.6 billion Purple Line light-rail project, which will connect suburban communities inside the Beltway just north of D.C. The Purple Line faced major delays owing to litigation and utility problems, among other troubles, after the ink was dry on Maryland’s agreement with its private-sector partner. The result was months of tumult, a construction contractor that walked away and an extra $250 million payment from the state to rescue the project.

Opponents will brandish the Purple Line’s travails and those of other public-private partnerships elsewhere as evidence that Mr. Hogan’s plan is folly that may saddle Maryland taxpayers with the bill. Those concerns deserve a fair hearing. But they will not negate the fundamental truth that the Washington area needs a robust transportation network — roads as well as mass transit — to sustain its dynamism, diversity and growth. Maryland’s portion of the Beltway and I-270 must be improved; the bridge must be rebuilt. And Mr. Hogan’s plan is the best feasible option for doing so.

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