A Lyft car drives next to a taxi in San Francisco in this file photo. (Justin Sullivan/Getty Images)

It was early evening in West Hollywood when Shereen Younes, 26, climbed into the front seat of a Lyft. It was Pride weekend in Los Angeles, and traffic was piling up along the route to her destination in the Hollywood Hills.

She chatted with the driver, Jesus, who was cordial — maybe a little too nice (he kept inviting her to dinner). Ten minutes in, she began to hear an “incessant beeping,” Younes said. He snatched a device from the center console and exhaled into a tube.

It was an ignition interlock device, meant to stop people from driving while intoxicated.

Younes said that when she asked Jesus about it, he became uncomfortable.

“And then he goes into how his car’s in the shop — he’s using this car as a loaner. I’m not sure what was true and what wasn’t,” she said. “In the moment, I’m like, ‘I’m gonna live-tweet this in case I die.’ ”

An ignition interlock device. (Allison Shelley/For The Post)

Over the past year, dozens of ride-hailing patrons have posted on social media and online message boards about similar experiences involving rides with drivers using portable breath-test devices. Issued by cities and states, the devices are meant to ensure that convicted drunk drivers, often chronic offenders, don’t drink and drive.

The devices prevent a vehicle from being started if the breath sample exceeds a set limit. At random times after the engine has been started, the device beeps, requiring the driver to provide another sample. The information is recorded and sent to the agency that ordered that the device be installed.

There’s only one problem: People who have been convicted of an alcohol-related offense within the past seven years aren’t allowed to drive for Uber or Lyft. The initial background check that drivers undergo is supposed to detect criminal and traffic convictions.

An interlock device in a car doesn’t necessarily mean that the driver has been convicted of driving under the influence. The car could belong to a friend or relative and can be used for ride-hailing if the driver is listed on the owner’s insurance.

But the presence of the devices raises questions for an industry that already has come under increased scrutiny for its screening of drivers, most recently after an Uber driver allegedly went on a shooting rampage in Kalamazoo, Mich., in February, apparently picking up fares in the process.

In February, Uber agreed to pay $28.5 million in settling two lawsuits that accused it of misleading passengers about its safety. The lawsuits claimed that although Uber used such phrases as “safest ride on the road” and “industry-leading background checks,” it did not scan the fingerprints of its drivers or check whether they were on the national sex-offender registry.

And in a case last year, an Uber driver picking up fares while driving on a revoked license was terminated only after a Charlotte television station brought to the company’s attention his charge of driving while intoxicated on New Year’s Day. At the time, North Carolina did not regulate ride-hailing services, meaning that the companies were not legally required to conduct follow-up screenings.

So after the initial background check, how do the services ensure that their drivers’ records stay clean? Do they regularly run routine checks, or are drivers required to report convictions?

Lyft says it checks driving records annually in all its markets. It checks criminal records based on the requirements of the cities or states where it operates. Those requirements vary widely.

Uber says it is “having conversations” about what makes the most sense. The company declined to say whether it conducted rescreenings of criminal or driving records of its drivers in unregulated markets, including Florida, Michigan and Vermont, while it contemplated such a policy. Some large cities in those states have adopted regulations of their own.

Uber says the background checks it conducts are sufficient to disqualify drunk drivers so there is no need to monitor for such things as ignition interlock devices.

“We have a zero-tolerance policy for DUIs, and our driver-screening process checks for them,” spokeswoman Nairi Hourdajian said in a statement.

(Washington Post owner Jeffrey P. Bezos is an Uber investor.)

Lyft says that it is reviewing its policy on interlock devices and that reports are currently handled on a case-by-case basis. The company booted a Washington, D.C., driver from its service in February after a passenger reported seeing him use an ignition interlock device.

“As soon as we received the passenger’s report, we immediately suspended this driver as our Trust and Safety team investigated the incident,” Lyft spokeswoman Chelsea Wilson said.

A ‘scarlet letter’ for drivers

It was around 5 p.m. on March 2, and Alicia Morales, 19, was in a Lyft, staring at her cellphone, when she heard her driver exhaling. She looked up to see him using an ignition interlock device.

“All of a sudden, he’s blowing into this thing,” said Morales, of Tempe, Ariz. “I got really hot. I was really sweaty . . . like, ‘Wow, I’m kind of nervous right now.’ ”

Afterward, Morales said the driver told her: “I’m sorry about that.”

She said she didn’t question him or inform Lyft, figuring “you know, somebody will report it.”

But, had it been late at night, she said, “I wouldn’t want to be in that car by myself.”

Then there’s the Jacksonville, Fla., couple who decided to try Uber for Saturday night dinner and drinks with friends. The driver had a 4.8 rating with customers, so they were “hopeful.”

The wife, Charlene Hewitt, recounted the incident on the website UberPeople.net, which describes itself as an independent community of ride-share drivers.

It was June. From the back seat of the car, Charlene Hewitt, 33, spotted a camera mounted to the dashboard.

“He said, ‘Yeah, it takes my picture and uploads it when I blow in here.’ I hadn’t noticed the Breathalyzer from the back seat.

“When we were almost to our destination, it started beeping. He had to blow and hum into the thing for what seemed like an eternity, almost missing our turn in the process. He has to do this every 20 minutes.”

Hewitt said she told the driver she thought it was “weird” they let him drive with a DUI. He explained that he had been charged with drunken driving multiple times — the latest one eight years ago — and had only recently had his license reinstated, so the court ordered the breath tester installed.

“He told us that every time he would drink, he felt the need to go somewhere,” she said in an interview.

She said she felt for the man, describing an interlock device as a “scarlet letter” for a for-hire driver.

At the same time, Hewitt, a former Uber Black driver who also used to operate a transportation company, said the optics reflected poorly on Uber. But she didn’t report the incident, thinking “enough people are probably gonna get freaked out by this.”

“I mean I can understand why someone would be nervous or uncomfortable,” she said. “I also thought that if this was my business, there’s no way in hell I would have a driver representing me [with something] so unprofessional.”

Patchwork of screening laws

To date, about 30 states and the District have adopted regulations for ride-hailing companies. Each state has its own set of rules. Some require checks against national criminal databases; others go deeper, scanning local police records too.

After the initial background check, many localities don’t require follow-ups — meaning criminal offenses could go unnoticed for months or even years if the company doesn’t take additional precautions. Two notable exceptions are Nevada and Virginia: Nevada requires drivers to be recertified annually, and they face immediate termination if they fail to report new convictions. In Virginia, drivers must notify the ride-hailing company of any incident that could jeopardize their employment, under penalty of civil or criminal charges or a yearlong ban. And in New York City, where ride-hailing drivers have to register with the city, officials are notified when any licensee is arrested — on or off duty — as with taxicab drivers.

In Chicago, the requirement on taxi drivers for notification is two days, and a DUI — on or off duty — would mean the driver is suspended from operating a cab.

In the taxi industry, which typically is more heavily regulated, drivers and cab companies are subject to penalties if they don’t alert authorities to criminal charges. But some taxi regulations are more relaxed than those of ride-hailing when it comes to drunken-driving convictions. While ride-hailing companies bar drivers who have had such convictions within the past seven years, cab services in San Francisco, for example, prohibit applicants from driving taxis only if they have two or more DUI convictions within five years.

The devices themselves are a problem of optics for Uber and Lyft, said Michael Fertik, who is known as a pioneer in the industry of online reputation management for companies and individuals.

“What it sounds like is a product marketing issue,” he said. “I don’t think it’s an indictment of their service. I think I would share alarm if I didn’t first understand. . . . I might assume that the interlock device was for the driver.”

At the same time, he said, in a universe of hundreds of thousands of cars that make up Uber and Lyft, there are going to be some quirks.

“You’ve got a solar-system-sized ecosystem now, and so you’ll probably see everything,” he said.

For riders, though, it’s about much more than optics. Passengers who say they’ve been startled by the sight of the devices worry about booking a ride with someone with a drinking problem or DUI conviction.

Younes, the customer in West Hollywood, came up with her own solution: She deleted the Lyft app from her smartphone. She doesn’t hold it against the driver that he had an interlock device, but the incident was bizarre enough that she hasn’t used the service since.

“Maybe at 2 a.m, I wouldn’t have been so cordial because it’s so dark and no one is seeing me,” she said. “There’s an ingrained fear in women that is always there, and it is heightened by your situation.”

“When that happened I was like, ‘I guess I’m done with this for a while.’ ”