(CNN) Transportation Secretary Pete Buttigieg said Monday that neither a gas tax nor a mileage tax would be part of President Joe Biden's sweeping infrastructure plan to be detailed on Wednesday.
"No, that's not part of the conversation about this infrastructure bill," Buttigieg told CNN's Jake Tapper on "The Lead" when asked whether a mileage tax, which would charge people based on how many miles they drive, would factor into paying for the plan.
He added that "no," a gas tax would not be a part of the plan either. Buttigieg also reiterated Biden's prior pledge not to raise taxes on Americans earning less than $400,000.
The absence of both taxes to fund the infrastructure proposal marks a shift from Buttigieg's comments Friday, when he indicated during a CNBC interview that both ideas could be on the table.
"I think that shows a lot of promise," Buttigieg said of the mileage tax. "If we believe in that so-called user pays principle, the idea that part of how we pay for roads is you pay based on how much you drive."
He continued, "The gas tax used to be the obvious way to do it -- it's not anymore, so a so-called vehicle-miles-traveled tax or mileage tax, whatever you want to call it, could be a way to do it."
Of the gas tax on Friday, Buttigieg also said that "if there's a way to do it that doesn't increase the burden on the middle class, we can look at it, but if we do, we've got to recognize that's still not going to be the long-term answer."
Biden will lay out the first of a sweeping two-pronged infrastructure and jobs proposal Wednesday, with the administration launching its expected months-long effort to pass proposals that will total between $3 trillion and $4 trillion, according to senior administration officials.
Biden will detail the infrastructure and climate piece of the proposal in Pittsburgh — where he launched his presidential campaign in 2019 — and is set to focus on repairing the physical infrastructure of the country while pushing for significant investments in climate infrastructure and research and development.
In conjunction with a second proposal focused on what's being termed the "care economy" with a focus zeroed in on key domestic economic issues, the plan marks a sweeping move toward enacting the key elements of the jobs agenda that Biden laid out in large part during his campaign for president.
Biden's proposal will mark the first step of what are expected to be lengthy negotiations with lawmakers on Capitol Hill, where Democrats have worked through their own versions of several key pieces of the proposal and are also in the midst of drafting potential revenue sources to pay for part, or all, of the plan, aides say.
Buttigieg on Monday cited encouraging conversations with both congressional Democrats and Republicans in emphasizing "a tremendous opportunity now to have bipartisan support for a big, bold vision on infrastructure."
"I hope we can work in good faith with folks across the aisle in Congress to get some votes there," Buttigieg said when asked of the possibility that Biden's first two major initiatives, the Covid relief package and now the infrastructure proposal, might not garner any Republican support.
"Ultimately it's up to them whether they are going to support something," he continued. "But we're going to work with them to try to shape it in a way that earns as much support as possible."
This story has been updated with additional details.