Solo travel is on the rise — hello, Amalfi Coast with strangers.

On a sunny October day, a small bus with 17 passengers left a mountain village in Italy, headed for the famed coastal town of Amalfi. The zigzagging road offered glimpses of spectacularly craggy cliffs, small red-roofed villages and the glittering Mediterranean. Inside the bus, increasingly raucous laughter, lots of loud chatter and the occasional whoop filled the air.

It wasn't a school field trip, a study-abroad program or a family reunion. Until the day before, most of the people had never met.

Other than three twosomes, all were complete strangers who'd signed on to take a tour of the Amalfi Coast designated as a trip for solo travelers. Some strangers shared hotel rooms. Others opted for single accommodations. But the group seemed to jell early on, hence the hoots and hollers from the back of the bus on the first full day.

This was a convivial group with the 11 solo travelers joined by a mother-daughter pair, a European couple, and a husband and wife from Canada. The group ranged in age from 27 to 66. Most were Brits.

They bonded over hikes to the top of Mount Vesuvius and along the famed Path of the Gods, during excursions to Naples, Capri and Amalfi, and to the ancient city of Herculaneum. At the small, family-run hotel where the group stayed, buffet breakfasts and communal dinners also fostered camaraderie that seemed most pronounced during dinner, perhaps helped along by the wine.

Firm numbers are hard to come by, but travel experts say solo travel, whether as part of a group or totally alone, is on the rise.

The Visa Global Travel Intentions Study 2015 found that solo travel continues on an upward trend, with 24 percent of respondents saying they traveled alone on their most recent international leisure trip, compared with 15 percent in 2013. A 2016 TripAdvisor study, querying more than 36,000 travelers in 33 countries, found that 34 percent had traveled alone.

"Whether you go independently or with a group, you are leaving behind the life that defines you on a daily basis and entering into a world that, whether in a big or small way, is on your own terms, and you're following your own interests," she said.

At Exodus Travels, the U.K. company that operated the Amalfi tour, 66 percent of its bookings came from solo travelers in 2016, compared with 50 percent the previous year, according to marketing and PR manager Robin Brooks. Additionally, the number of U.S. travelers jumping on the solo bandwagon has exploded. From 2015 to 2016, Exodus saw a 141 percent increase in the numbers of Americans booking without a companion.

Solo travelers are a big part of all of Exodus' tours, but the company has specifically designated 56 trips on its website as solo departures, catering to individuals rather than couples, families or groups of friends.

"People are looking for new experiences, new challenges, and we see the increase in solo booking as a continuation of this track," Brooks said. "Today's individuals and those of us who have that sense of wanderlust want to do things that make us happy, and if you don't have a traveling companion, that doesn't need to hold you back anymore."

Indeed, there are many reasons to travel solo, either by necessity or by choice.

"So either I have the choice of sitting at home or going for the family holiday with my friends," said Pressley, who's been on numerous Exodus tours.

Instead, he opts for solo travel because he can decide exactly what he wants to do and when he wants to do it, without making compromises to fit a companion's interests or schedules.

Caroline Woodhouse, a 50-year-old divorced law librarian from Bristol, England, finds that she has the time and urge to travel but not necessarily a regular travel companion, which until recently had been one of her college-age children. Another benefit of a group tour also appealed to her.

"I have always organized every detail of all of our holidays and so was very attracted to the idea of someone else doing the hard work of drawing up itineraries, organizing travel, guides and accommodation instead of me," she said.

Woodhouse is planning a three-week trip to Peru as a solo traveler: "Going on this kind of holiday will enable me to be more adventurous and go to some of the places I would never go on my own."

"Although I had friends and family to travel with, I decided to go alone and basically just try something different and do something a bit random," she said.

The Amalfi trip was the third Exodus tour for widow Moyra Storey, 66, a retired physiotherapist from Crieff, Scotland.