You might want to think twice the next time you call for a taxi, Uber or Lyft — or at least bring along some sanitizer.
A recent study suggests taxis, rental cars and ride-hailing vehicles are full of germs. The report echoes similar findings in recent years that show how various means of public transportation, primarily buses and subways, can be hotbeds of bacteria.
A swab-yielding team from NetQuote, an insurance comparison site, took samples from seat belts, door handles and window buttons on random taxis and ride-hailed vehicles. NetQuote swabbed the steering wheel, gear shift and seat belts in three random rental cars.
The testing was done in South Florida, "a region in which a strong driving culture is present, but also one in which rental cars and ride-sharing services are quite commonly used by locals and tourists alike," according to NetQuote.
Testers expected taxis to yield the highest amount of bacteria, as cleanliness seems to be the biggest complaint people have with taxis. But when lab results came back with counts for the number of colony-forming units (CFUs) and bacteria present, it was actually ride-hailed cars that turned out to be the germiest. The study found more than 6 million CFUs per square inch on average, while rentals averaged a much smaller amount of 2 million CFU/sq. in. Taxis had an average of just more than 27,000 CFU/sq. in.
"To put it in perspective," the report notes, "rideshares averaged almost three times more germs than a toothbrush holder," while the number of microorganisms in both rideshares and rental cars was more than those found on toilet seats and in coffee pot reservoirs.
The research team at NetQuote did not single out which ride-hailing companies it tested, "in the interest of not characterizing specific companies unfairly," according to a spokesperson.
In response to an inquiry from CNBC, an Uber representative said the company doesn't directly inspect cars for cleanliness. However, Uber said its two-way feedback system — where riders and drivers rate one another after each ride — is the main method through which vehicle cleanliness is noted and addressed. If a driver's car is dirty, they'll likely get poor ratings and hear about it from local Uber teams, the spokesperson added.
A representative from Lyft did not respond to CNBC's request for comment.
Of course, "not all germs are harmful," the study notes, but high bacteria levels increase the chance that harmful microorganisms are present. Additionally, some potentially harmful germs, such as bacillus, cocci and yeast, showed up repeatedly in the samples.
Although taxis were the cleanest rides of the three tested, they were by no means free of germs. The swabs taken in taxis showed that the most germ-filled surfaces were seat belts, with 26,000 CFU/sq. in. Meanwhile, seat belts in rideshares had 38 times more bacteria.
Taxi door handles had 1,570 CFU/sq. in., around 55 times more bacteria than in a typical car door handle, the study notes, while taxi window buttons were surprisingly clean, with just 23 CFU/sq. in.
In the rental cars tested, both the steering wheels and gear shifts had more than 1 million CFU/sq. inch, while the seat belts showed a relatively low rate of 403 CFU/sq. in.
Even in your own car, it's likely almost impossible to avoid germs on the ride to and from the airport, but there are ways to leave some of the worst bacteria behind.
"When you rent a car, take a moment to wipe key surfaces such as the steering wheel and gear shift with a soap-based wipe before you touch them," the report advises. "And once you leave the cab or rideshare, wash your hands as soon as possible — and avoid touching your face until you do."
There are plenty of products that riders can keep handy in order to fend off the legions of germs, experts say.
"The Clean Well sprayer is an all-natural, alcohol free, version that is very popular for people looking for something as an alternative to the very-popular Purell," said Paul Shrater, co-founder and COO of Minimus.biz, a site that sells travel-sized products.
"One thing to note is that once you call something 'sanitizer,' 'antibacterial' or 'disinfect' it is actually considered an over-the-counter drug, and regulated by the U.S. Food and Drug Administration because you are making specific medical claims," said Shrater.
"That's quite different than something that just claims to 'clean' like a regular soap," said Shrater. "So if you are really looking to kill germs, look for something that has one of those phrases."
— Harriet Baskas is the author of seven books, including "Hidden Treasures: What Museums Can't or Won't Show You," and the Stuck at the Airport blog. Follow her on Twitter at @hbaskas. Follow Road Warrior at @CNBCtravel.