PALO ALTO (CBS SF) — A new documentary airing at the Sundance Film Festival chronicles how a public bus in Silicon Valley has turned into an unofficial shelter for the homeless.

Commonly referred to as “Hotel 22,” the bus has become a mobile symbol of the affordable housing challenges in one of the country’s wealthiest areas.

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Filmmaker and Stanford student Elizabeth Lo captures scenes from an overnight bus ride, detailing a fight breaking out while other keep warm buried in their hoodie sweatshirts. At the end, the unfazed bus driver wakes everyone up when they arrive in Palo Alto.

Lo, who heard about the phenomenon while living in Palo Alto as a student at Stanford University, writes about the experience for a New York Times opinion piece. “It was such a contrast to my image of Silicon Valley that I decided to ride the bus myself,” she said. “What I saw seemed like a microcosm of the challenges confronting this dispossessed population. And despite mostly keeping to themselves, the sleepers sometimes came into direct conflict with late-night commuters who also ride the bus at those hours.”

VIDEO: “Hotel 22” Trailer

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The Valley Transportation Authority’s 22 bus operates 24 hours a day between the Eastridge Mall and Palo Alto. For many, a night spent circling the South Bay on the bus is the best option to keep out of danger and the cold.

The VTA doesn’t have a good estimate on how many or how long the homeless have been visiting “Hotel 22,” but say it has been years. Agency representatives have said they don’t mind, so long as the homeless pay their fare.

An estimated 5,000 people are homeless on the streets of Santa Clara County every night.

WATCH: KPIX 5 Report On Hotel 22

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