The police officer who pulled her over in Warminster immediately asked for her driver’s license, Estela said, but she didn’t have one. She’s undocumented, not legally permitted to drive in Pennsylvania.

A tow truck arrived, her car soon on its way to an impoundment lot. The thousands of dollars it would cost to get it back wasn’t her biggest worry at that moment.

“Other people have been stopped and turned over to ICE,” said Estela, 40, who came to Philadelphia from Mexico and agreed to speak if her surname was withheld. “Thank God it didn’t happen to me.”

For Estela and others without legal status, the threat of deportation looms each time they climb behind the wheel and head to work or school or the doctor. Or, in her case two years ago, to pick up an employee at her metro-area cleaning business.

Now, Pennsylvania faces renewed debate — moral, legal, and financial — over allowing undocumented immigrants to get driver’s licenses, which is approved in 15 states but struggles to gain traction here.

Supporters cite studies showing access to licenses promotes highway safety and economic growth.

Under a proposed law, migrants would have to undergo the same driver’s training as everyone else, and prove their familiarity with traffic laws. They would also pay for vehicle registration, inspections, and insurance, generating millions of dollars for the state and private insurers.

Money would flow to small businesses, too. Cars need mechanics. Cars need parts. They need floor mats and seat covers and those tiny little air fresheners shaped like trees.

A spokesperson for House Majority Leader Kerry Benninghoff, a Republican who represents Centre and Mifflin Counties, did not respond to specific questions about offering licenses to undocumented people. The spokesperson said the legislation would need to be vetted by the Transportation Committee before it rises for any larger discussion.

Opponents of licensing laws say the rules raise questions: If people do not have permission to be in the country, why would the government authorize them to drive?

Some people agree with that.

In Minnesota, 51% of voters who responded to a poll about refugee resettlement opposed licenses for undocumented drivers. In New York, which barely passed a licensing bill last year, opposition stood at about 50%.

The debate has roiled Massachusetts, where no law has passed despite projections of new money — $1.2 million in sales taxes on such products as tires and parts, an additional $3.8 million in gasoline taxes, and $6 million for license and inspection fees during the first three years.

“My problem with giving licenses to people who are undocumented is just that. There’s no documentation to back up the fact that they are who they say they are,” Republican Gov. Charlie Baker told New England Cable News last year.

For immigrants, the prospect of legal identification is huge.

Many already drive, their every trip to work or the grocery store fraught with the life-changing risk of being stopped by police and deported. A valid state identification would prevent that, and make it easier for people to do everything from picking up medicine at the pharmacy to picking up their child from school.

“Obtaining a driver’s license should not be used as punishment for immigration status,” said John, 24, who was 9 or 10 when he came with his parents from South Korea to New Jersey.

He’s still undocumented. And he still remembers the humiliation of constantly begging rides from friends, family, and neighbors. One time his mother grew sick and fainted, and the family couldn’t drive her to the doctor. It was terrifying.

Now he lives in a state that allows immigrants to get licenses.

“It’s very freeing,” he said. “I can take my parents anywhere they need to go. And I can use it as identification.”

The fight has been waged in Pennsylvania as recently as last year, at a time when the Trump administration claimed that licensing laws made it easier for terrorists and criminals to fraudulently obtain documents.

Now it’s being pursued under the Biden administration, whose immigration agenda includes a path to citizenship for 11 million undocumented people, and at a time of pandemic crisis, when many migrants are working frontline jobs to provide food and services across the United States.

“The state legislature of Pennsylvania needs to recognize the contributions of these essential workers and their families,” said Patty Torres, organizing director of Make the Road PA, “and provide much needed dignity, relief and respect by granting drivers’ licenses.”

Make the Road PA is part of a statewide coalition of advocacy, labor, faith, and business organizations united as Driving PA Forward. On Feb. 17, the group plans to begin a campaign of public and private events to support the bill introduced by Democratic State Rep. Danilo Burgos of Philadelphia.

Burgos says undocumented migrants contribute to society and the economy but don’t get “the equal protections and basic rights that the rest of us enjoy, such as the ability to drive safely to work, school, and businesses.”

Under House Bill 279, people could apply for driver’s licenses without having a Social Security number, instead using a federal taxpayer identification number or a combination of other records such as a foreign passport or consular documents.

“Getting behind the wheel is a privilege that many people take for granted,” said Democratic State Sen. Tim Kearney, who represents parts of Chester and Delaware Counties and plans to introduce the bill in the Senate. “But this basic need of everyday life is not guaranteed for undocumented residents of Pennsylvania.”

Efforts to reach Republican Transportation Committee Chairman Tim Hennessey were unsuccessful. Majority Policy Committee Chairman Martin Causer also could not be reached.

Advocates cast this as a human-rights issue, specifically about the right to freedom of movement. They note that citizenship is federally regulated, and licenses are granted by the states, so one has no bearing on the other.

“We’re human beings, we’re part of this society, part of the community,” said Driving PA Forward coordinator Luis Larín. “We’re part of the fabric of Pennsylvania, no matter the immigration status.”

The bill includes a strict privacy provision, key in a state that reaped millions of dollars by selling drivers’ personal data. In Vermont, the Department of Motor Vehicles was sued after records revealed it routinely shared drivers’ personal information with agents of U.S. Immigration and Customs Enforcement.

Denying licenses is simply unfair, said Blanca Pacheco, codirector of New Sanctuary Movement of Philadelphia. Migrants pay taxes like everyone else, dues that go to pave roads and build bridges and operate the machinery of traffic regulation.

“What do we get in return? Why are we just machines to earn money?” she said. “If the state and the country is making us pay taxes, and making us contribute, we should be allowed to drive.”

Having a license, she said, eliminates a threat of family separation when police stop a car. In some cases, parents drove to work in the morning and never came home to their families, because they were detained and deported.

Pacheco battles misconceptions in advocating for the law: No, a driver’s license does not lead to citizenship. It doesn’t make anyone eligible to vote. Nor does it grant access to state or federal benefits. It simply confirms a person’s name, address, and eligibility to drive.

In Colorado, drivers were estimated to save $57 million in premium payments as roads became safer, and insurance companies to earn $102 million in new revenues, according to the Colorado Fiscal Institute. In New Mexico the rate of uninsured motorists dropped 60% — in Utah it was 80%. California saw an 18% increase in registered organ donors.

In New Jersey, home to one of the nation’s largest undocumented populations at about 475,000 people, implementation of a new law that provides licenses has been delayed by the pandemic. Delaware allows undocumented immigrants to legally drive.

Pennsylvania is home to an estimated 164,000 undocumented immigrants, and about half would seek licenses within the first three years, according to the Keystone Research Center and its Pennsylvania Budget and Policy Center. Migrants would buy about 20,486 cars during that time, and the state would see an estimated $13 million increase in taxes and fees.

Estela came to Philadelphia nearly 20 years ago, and now runs a cleaning company that serves businesses in Pennsylvania, New Jersey, and Delaware. Demand has been high during the pandemic. She’s often traveling at night.

“It will be life-changing if we can get a driver’s license,” she said. “We are forced to drive because it’s needed, it’s a need.”