Democratic presidential candidate and billionaire Michael Bloomberg was flummoxed by a San Francisco's subway turnstile Friday, despite his famously taking the subway to work while he was mayor of New York City.

Bloomberg was in the midst of a tour of the Bay Area when he, and a gaggle of aides and press, descended into a San Francisco BART - Bay Area Rapid Transit - station to hop a ride to nearby Oakland, California, Friday morning.

In a video, shot and tweeted out by San Francisco Chronicle reporter Joe Garofoli, Bloomberg can be seen holding a plastic Clipper fare card as he approaches a subway turnstile.

“Much cleaner. Much more modern.” ⁦@MikeBloomberg⁩ on how BART compares to NYC subway after he rides from SF to Oakland pic.twitter.com/ZTbF7oCs1p — Joe Garofoli (@joegarofoli) January 17, 2020

Michael Bloomberg was caught on video attempting to insert a contactless fare card into a turnstile while at a San Francisco BART station Friday

It took several seconds before an aide rushed over and showed him where to tap the card

Bloomberg was trying to use the BART to get from San Francisco to Oakland, California

Bloomberg's forward motion comes to an abrupt halt, though, as his attempt to get through the turnstile is stymied by his not knowing how to use the fare card properly.

Instead of 'tagging' the contactless Clipper card on the designated spot on the top of the turnstile, Bloomberg tries to shove the card into a slot on the side of the machine.

It takes several seconds for an aide to rush over and show him what he needs to do with the card, before he's able to make it through the turnstile.

The San Francisco Chronicle pointed out that Bloomberg was attempting to put the Clipper card into the slot where paper tickets are supposed to go.

Bloomberg posted this photo of himself at the subway station and said that he is a 'big believer in public transportation'

Bloomberg also noted that reducing carbon pollution by investing in public transportation is part of his campaigning points

Bloomberg is seen here in 2014, after successfully swiping his MetroCard through a New York City subway station turnstile

Bloomberg (in 2002) is seen riding a New York City subway. He famously used the train to get to work and home while he was mayor

Bloomberg posted a photo of himself at the BART station on Instagram, writing that he's 'a big believer in public transportation and its ability to reduce our carbon footprint. That’s why I’m making investing in public transportation a centerpiece of my strategy for cutting U.S. carbon pollution by 50% by 2030.'

Bloomberg was known for taking the subway to work while he was mayor of New York City from 2002 to 2013. But, unlike in San Francisco, the MTA requires passengers to swipe a MetroCard through a reader on the top of the turnstile.

The billionaire's BART issue, however, echoed a similar subway fare payment problem that Hillary Clinton had in New York City in 2016, when she was on the campaign trail prior to the 2016 presidential election.

Clinton, surrounded by press and aides, was caught on camera, suffering the humiliation of having to swipe her MetroCard through the turnstile nearly five times before it went through while she was at a subway station in the Bronx.

Bloomberg took the BART to Oakland, where he met with Mayor Libby Schaaf outside the popular Beauty’s Bagel Shop, before heading to Monterey, California, where he talked about climate change and his plans to plans for reducing carbon emissions and protecting natural resources, according to the Mercury News.