The Northern Virginia Transportation Authority is preparing for a pivotal challenge to its ability to fund long-awaited projects with more than $300 million in controversial new regional taxes, officials said. Critics, including the Loudoun County Board of Supervisors, are prepared to argue the NVTA does not have the constitutional right to impose the taxes under the Virginia Constitution.

Rather than face a future lawsuit that could upend transportation projects already under construction, NVTA asked for a Monday trial in Arlington County Circuit Court that the authority hopes will validate its right to issue bonds that will be paid by the taxes.