Will the $6 billion pledge to make transportation more sustainable be enough? Experts weigh in.

The funds to help states make transportation more sustainable have been promised, but will they be enough to propel the U.S. toward its emissions goals?

While it's a step in the right direction, the $6.4 billion pledged by the Federal Highway Administration to help states fund projects to reduce greenhouse gas emissions will barely make a dent in the funds needed to help the U.S. meet its goal to be carbon neutral by 2050, experts said.

Transportation Secretary Pete Buttigieg announced last week that states would receive the money -- part of a $1 trillion infrastructure package passed by Congress in November -- over five years to create projects that support widespread use of electric vehicles and trail facilities for pedestrians and bicyclists.

"It's a good start," Tom Moerenhout, a research scholar at Columbia University's Center on Global Energy Policy, told ABC News. "But, it's not a lot of money."

It will likely require more than $100 billion "to really make a dent into road-based or transportation-based carbon emissions," which are the largest source of carbon emissions in the U.S., Moerenhout said.

While roads, bridges and train lines have "really long lifespans," the decisions states make on where to allocate the funding will need to be strategic, as they will "stick with us through 2050," Elizabeth Irvin, a senior transportation analyst at the Union of Concerned Scientists, told ABC News.

"That's funding for states to work on transportation projects, where they're explicitly taking into account both emission reductions and sustainability and also environmental justice," Irvin said. "Those are all really important things."

In the coming years, there will be a significant shift in the number of electric vehicles on the road, despite the war in Russia threatening to further disrupt the supply chain, Randy Bell, director of the Global Energy Center at the Atlantic Council, a nonpartisan think tank, told ABC News.

The changing market has been evident in the release of more electric crossover and SUVs, which is "what Americans want to drive," Rawn said.

On Tuesday, Bill Ford, executive chairman of the Ford Motor Company, announced the first shipment of the F-150 Lightning, the first electric version of the top-selling truck in the U.S. for 45 years. Ford had to stop taking orders due to the "tremendous interest" in the Lightning, Ford said, adding that it sold out soon after the plans were announced last year.

The need for charging infrastructure to power these EVs will be "huge," Bell said, echoing the need to spend money wisely.

"EV adoption is not uniform around the country," Bell said.

The infrastructure for charging stations will also take the burden off families from having to install charging capabilities at home, Carol Lee Rawn, senior director of transportation at Ceres, a sustainability nonprofit, told ABC News.

"So you don't have to worry about having a plug at your house," she said. "You can plug when you go shopping, or when you go to work, and it's also extremely helpful for businesses that are interested in transitioning to electrification."

In addition, policymakers will need to consider infrastructure that allows people to walk and ride bikes and scooters safely, Rawn said, adding that E-bikes are becoming a viable alternative for many people.

Countries are now sprinting to meet the ambitious pledges made at COP26, the United Nations Climate Change Conference, in October 2021.

The Biden administration has continued to roll out a steady stream of initiatives to ease emissions from the transportation sector.

In December 2021, the Environmental Protection Agency announced its strictest vehicle emissions standards ever for cars and light trucks from model years 2023-2026. In February, the Transportation Department gave states the go-ahead to build electric car charging stations. And earlier this month, the National Highway Traffic Safety Administration issued new standards for vehicles sold in the U.S., requiring the average fuel efficiency to be at least 40 miles per gallon starting in 2026 -- up from the 28 mpg standard enacted under former President Donald Trump.

Currently, the U.S. is not on track to meet its 2030 or even 2050 goals, Moerenhout said, adding that it will be especially important for governments to incentivize the reduction of emissions.

"I think Europe has shown that with tightening fuel emission standards, you can move people into more sustainable practices and incentivize electrification," Moerenhout said. "But in the U.S., it has just been far too sporadic."

With the Russian-backed conflict in Ukraine now detracting from the sense of urgency toward climate change, it will be imperative that governments find a way to address energy security and climate action together, Bell said.

"So you may end up with a more pragmatic pathway towards climate action, which ultimately becomes more economic, becomes more politically palatable and becomes much more realizable in the short to medium term," he said.