It's a meet-cute story that couldn't have existed just two years ago.

Without Uber's carpool service, UberPOOL, introduced to Philadelphia in February 2016, Nick Marzano and Melissa Schipke would never have shared a ride last December during a heavy downpour, would never have started chatting — and would never be planning a 2018 wedding.

"I've never met anybody that I connect with on so many different levels, and I credit Uber for that," Marzano said.

Ride-hailing apps have reshaped the city's transportation environment. Now with the addition of UberPOOL and the competitor Lyft Line, in which passengers save money by sharing a ride with others heading in a similar direction, they have also created a novel playing field for the eternal human pursuits of love, companionship — and, perhaps most often, sex.

These meetings by the glow of dashboard lights present an unfamiliar social arena, said sociologist Elijah Anderson, who analyzed how Center City's urban spaces shape civility, or the lack of it, in his book The Cosmopolitan Canopy. They can be refreshingly egalitarian, mixing people who might otherwise never interact. They also create encounters that can be awkward, uncomfortable, or worse.

Ride-sharing, Anderson said, "brings out new opportunities for these riders, but also challenges or even dangers."

Especially when passengers are under the influence, he said, "there are no guarantees."

While riders say that most Uber and Lyft trips are uneventful, encounters are common enough that Uber's website addresses them: "Don't touch or flirt with other people in the car. As a reminder, Uber has a no-sex rule. That's no sexual conduct between drivers and riders, no matter what."

Nevertheless, Uber driver Gary Dages of Clementon has watched a few love connections — and some near-misses — unfold in his rearview mirror.

Once, strangers he picked up in Manayunk made an instant connection, and exchanged phone numbers. Another time, he said a man riding in his car struck up a conversation with a woman. After she got out, Dages recalled, "I said to him, 'Why didn't you get her number?' He kicked himself for the remainder of the trip."

Once the moment had passed, there was no way to reconnect. "You snooze, you lose."

Marzano, 35, and Schipke, 30, are both outgoing, civically active and driven — and, as they quickly learned, they share plenty of mutual friends. They even once exchanged a few messages on the dating app Bumble. But that never resulted in a date, and they didn't recognize each other on Dec. 6, 2016, when they both walked out of 1500 Spring Garden St. in search of a ride. He was getting out of work, and she was leaving an event for Penn State alumni. She was heading home. He was going to a date.

"I looked up and was like, 'Oh that guy's really cute,' " Schipke remembered.

When their UberPOOL, a Toyota Camry, showed up, Marzano got in the front seat and Schipke shared the back with another passenger. The two remembered talking over the other woman.

"I'm sure the entire time she's just watching this go down," Marzano said. "We're cracking jokes, figuring out all the connections we had."

"The standard flirting," said Schipke.

The two exchanged numbers and met for drinks a week later. About six months after that, Marzano proposed. They're hoping by getting their story out they'll find one more name to add to the guest list — the man who drove the Uber the night they met.

Still, most Uber romances aren't exactly fairy tales.

Often, they begin after last call: A guy, hoping to squeeze the last minutes of possibility from his night, looks over and spots the most beautiful girl in the whole wide car.

Eli Jones, 22, of South Voorhees, once found himself sharing a late-night Uber ride with a woman he had hooked up with once and never called. He tried to strike up a conversation, angling for one more drunken liaison. It didn't work out. "She was crazy. But she was very quiet in the Uber," he said outside the Uptown Beer Garden on a recent Wednesday evening. Then, he asked a reporter if she wanted to join him for a drink.

Aminda Leme da Silva Santos said an Uber driver caught her attention as she rode in a meticulously kept red Cadillac to an appointment in South Philadelphia. He was tall with a deep voice, she recalled, and she noticed him glancing at her in the rearview mirror.

"I thought he was going to ask for my number," Leme de Silva Santos, 42, said. "He was taking too long, so I asked him for his."

They didn't date for long, but she still thinks a car is as good a place as any to meet someone.

"It's all an opportunity," she said. "The bar is usually worse, in my experience, because people are usually drunk."

But for every harmless flirtation, there are unwelcome advances, or even perceived threats.

Some women have developed strategies to cope with aggressive behavior. Katy Kopenhaver,  25, of West Chester, said a couple of college students were relentless in hitting on her and a friend, continually asking questions like, "Where are you guys going?"

"I asked the Uber driver to drop them off first," Kopenhaver said. "I didn't want them following me."

Men, too, described uncomfortable moments.

He laughs about it now, but Max,  22, of East Falls, who declined to give his last name, said it got awkward when an intoxicated woman once spent a 3 a.m. Uber ride from Temple to South Philadelphia trying to physically pull him into the backseat with her.

The driver was no help. "He was like, 'You should go back there!' "

A 22-year-old University of Delaware student who did not want his name printed said he's seen both opportunity and hazards.

"I'm straight as far as anyone I know is concerned," he said, "but I do under the right conditions swing the other way."

He shared an UberPOOL with a man leaving the Firefly Music Festival, and in the course of the 15-minute ride agreed to go to the man's hotel room to use drugs. What happened next, "depending on how you look at it, it could've been sexual assault."

There have been reports of sexual assaults, attacks, and kidnappings associated with ride-hailing apps around the world. An Uber driver was convicted of sexually assaulting a 24-year-old woman in 2015, in a ride from Center City to Norristown.

The safety of passengers and female drivers concerns Angela Vogel, an Uber driver, who thinks the company should do more to protect them. Behind the wheel, she has faced everything from minor pests to extreme violations, like the man who tried, for a nearly half-hour ride, to determine how much money it would take for her to join him in his apartment.

"I'm not like a lot of women — and, frankly, a lot of women who are driving aren't like a lot of women," Vogel, 36, said. "It takes an attitude that you can fight back."

Vogel responds with a stern look, or a threat to boot the offender from her vehicle. Uber and Lyft cite their rating systems as effective accountability tools. Passengers and drivers can rate each other, and with low-enough ratings both could be suspended or barred from the companies' apps. Both companies also won't match a passenger or driver with someone who has given them a low rating. Of a five-star possible rating, Lyft sets that bar at three stars or fewer.

"My concern is, I'm going to rate them low, and then they're just going to go harass another driver," Vogel said.

She believes, though, that Uber shies away from providing drivers more training because it would weaken the argument that they are independent contractors, not employees. Uber declined to respond, referring only to its written policies.

That said, some have found that the worst thing about Uber — that you really never know whom you'll be getting into a car with — can also be the best thing.

And sometimes, amid all that love, lust, and leering in ride-sharing, there are just decent people, looking out for one another.

Josh Mermelstein, 27, was headed to his home in Northern Liberties at 3 a.m. one night when a woman, drunk to the point of incoherence, ended up in the car with him. Her friends had tried to send her to a PATCO station; instead, the Uber driver let her out at Mermelstein's stop. Mermelstein finally coaxed her address out of her.

"I called a new Uber and put her in it, and sent her home. It was like $50," he said. "I figured it was good karma."