Uber and Lyft want cars to have front license plates. Pennsylvania is one of 19 states without them.

On Thanksgiving eve, one of the biggest drinking nights of the year, many revelers in Philadelphia ordered a ride from Uber or Lyft.

The rideshare apps have recently taken to reminding users to make sure before getting in that the license plate of the car they ordered matches the one on the vehicle that arrives. Those warnings were spurred by stories like that of a New Jersey woman who in March ordered an Uber in South Carolina, mistakenly got in the wrong car, and was kidnapped and killed.

But what if riders can’t easily see the license plate of the car coming to pick them up?

This year, Ohio lawmakers decided to stop requiring most registered vehicle owners there to have both front and rear plates. If the policy takes effect as planned on July 1, Ohio will join Pennsylvania and 18 others that require only back plates. New Jerseyis among the 31 states, plus the District of Columbia, that require front and rear.

Uber and Lyft are supporting a bill in the Ohio Senate that would continue to require front plates for vehicles.

“We believe the requirement of a front license plate can create a safer environment for all users,” Kevin Kerr, a public policy official for Uber, wrote in a letter to the president of the Ohio Senate.

The combination of front and rear license plates gives the public, police, and surveillance and traffic cameras more opportunities to identify a vehicle used to commit crimes. Proponents of rear-only plates say issuing one plate is less expensive for states and divers.

Pennsylvania issued front and rear license plates for just a few years, between 1946 and 1952, according to PennDot. Since then, drivers have only needed a rear plate. PennDot historical records don’t give a reason for the brief two-plate policy.

PennDot hasn’t gotten any recent requests to bring back front license plates, a spokesperson said. Officials at the Pennsylvania Chiefs of Police Association have not discussed front plates, said Scott Bohn, chairman and past president of the association and the police chief in West Chester.

The International Association of Chiefs of Police supports front license plates.

"It’s another tool in helping us to fight crime,” said Daniel G. Sharp, chair of the association’s highway safety committee and the top cop in Oro Valley, Ariz. “It makes the community safer, and that’s the bottom line.”

Sharp, who has been in law enforcement for 41 years, has brought up the issue occasionally over the last few years to Arizona lawmakers. “There just hasn’t been a real appetite,” said Sharp, who is also chair of the Arizona Automobile Theft Authority. “It’s a political will thing.”

He blames “the car enthusiasts.”

“When you start looking at the genesis of a bill or legislation proposed, oftentimes it is somebody who says, ‘Gee, I have this exotic sports car, and I just don’t want to put a license on the front,’” Sharp said. “Because they think it doesn’t look good.”

“It’s not a cosmetic thing,” he said. “It’s a safety thing."