The Maryland Board of Public Works — Treasurer Nancy Kopp (D), Gov. Larry Hogan (R) and Comptroller Peter Franchot (D) — in Annapolis on Wednesday. (Michael Robinson Chavez/The Washington Post)

IN ADVANCING a proposal to add privately built toll lanes, and desperately needed road capacity, to the most traffic-clogged highways in Maryland — Interstate 270 and the Capital Beltway — a state panel on Wednesday struck a blow for common sense. It also signaled to local elected officials in the Washington suburbs that while their legitimate concerns about the plan will be taken into account, the project, which would improve the daily lives of hundreds of thousands of commuters, should not be derailed.

The vote, by the state’s three-member Board of Public Works, authorizes the state to start fielding bids from contractors who would build and operate the toll lanes and keep most of the revenue. It was a far cry from final approval of Gov. Larry Hogan’s proposal, which must still undergo a comprehensive environmental review among other tests. Mindful of local opposition, the board, consisting of Mr. Hogan (R), Comptroller Peter Franchot (D) and Treasurer Nancy K. Kopp (D), also prioritized the I-270 portion, which would not require the destruction of any homes, and split off two other more controversial major phases — adding new lanes to the Beltway and American Legion Bridge in Montgomery and Prince George’s counties — for separate future votes authorizing bids so that opponents’ concerns can be fully aired.

Nonetheless, by greenlighting the bidding process, the board recognized the certainty that without upgrades to those major suburban arteries, traffic will get much worse as the area’s population swells in the next 20 years — a threat to the region’s prosperity.

Mr. Hogan has championed major transit improvements in the Washington suburbs, a fact now ignored by opponents of his road-widening blueprint. They argue, wrongly, that more bus and rail options can negate the need for expanded road capacity. Every projection of population, employment and vehicle usage suggests the opposite.

The Hogan proposal calls for a public-private partnership that would leave existing lanes free and put construction and management of the new toll lanes in the hands of a company that would bear the costs and take the risks of the $11 billion project. Little wonder that, according to one poll, more than 6 in 10 residents of the Washington region, and 55 percent in the Maryland suburbs, support Mr. Hogan’s plan.

It’s critical that details, and the bids, be subjected to intense scrutiny to ensure that terrain, waterways and taxpayers are all protected. But some suburban politicians, all of them Democrats, are not focusing on oversight. They’re trying to kill the project by peddling canards, warning that taxpayers will be at risk; that traffic will not improve; that drivers will be subject to unaffordable tolls.

In fact, Maryland taxpayers will be shielded from expense if state officials strike the right deal. Commuting times are likely to improve somewhat if toll lanes are added in Maryland, as they have in Virginia; more to the point, they will worsen dramatically without the new lanes. And no one will be forced to use the new toll lanes.

Officials must insist that the new lanes’ configuration minimizes the impact on private property — both the relatively small number of houses that may be razed and the larger number of backyards that might be affected. But opposing road improvements is a head-in-the-sand approach to transportation and the daily lives of commuters.