The number of people living in their vehicles in Oakland has more than doubled over two years, newly released data show, prompting the city to tackle its homeless crisis by designating parking areas specifically for RVs that now crowd the streets.

The results of Oakland’s citywide homeless count — a one-day survey conducted every two years — showed 1,430 people living in a vehicle of some kind on Jan. 30, the day of the count. The number of vehicle dwellers skyrocketed from two years earlier, when 618 people were living in their cars, a 131% increase.

Roughly half of them live in cars and vans: 727, up from 314 two years earlier. Another half live in recreational vehicles, or RVs: 703, up from 304 in 2017.

In all, the vehicle dwellers represent 35% of Oakland’s homeless population of 4,071 people, the report showed.

“The fact that all of our numbers went up so dramatically is not a surprise to those of who live and work in Oakland and drive around the city because this is what we see,” said Lara Tannenbaum, manager of the city’s community housing services. “We already started to shift our strategies just based on what we were seeing, It didn’t take hard numbers to tell us that the numbers of people living in vehicles had increased.”

The city opened its first “RV safe parking site” with plans to open two more in coming months.

Homeless advocates say the new numbers portray the growing crisis on the streets of Oakland.

Candice Elder, executive director of East Oakland Collective, a nonprofit focusing on racial and economic equity, blamed the rise of people living in vehicles on a lack of housing for low-income people, and a lack of shelter for those without homes.

“People are having better luck living in their RV or their car,” Elder said. “There are people who either are low- to mid-income and are purchasing cars just to live in because it’s still cheaper and more affordable than the rent that we are experiencing in the Bay Area.”

The rapid rise of people living in vehicles comes as the overall number of homeless people in Oakland has also grown at an astonishing rate, as The Chronicle reported in July when Alameda County released countywide results of January’s one-day homeless count.

The survey, which is conducted across the country and reported to the federal Department of Housing and Urban Development, is done on a single night in January. EveryOne Counts conducted the report and is the same organization that does the official homeless count for Alameda County. Not every city request an individual report. Oakland commissioned its report, which is 87 pages packed with information about the city’s homeless.

According to the report, 14% of homeless people suffer from mental health issues. Another 13% have lost their job. And 11% couldn’t afford rising rent. The vast majority, 70 percent, of Oakland’s homeless people are black, yet black people make up just 24% of the city’s general population.

While Oakland counted more than 4,000 homeless people this year, officials counted 2,761 in 2017 — a 47% increase and one of the largest two-year increases of any California city.

The jump meant Oakland’s per capita homeless rate — 940 for every 100,000 people — surpassed San Francisco’s rate of 916 per 100,000, and Berkeley’s 898 at a time when cities everywhere are struggling with a crisis driven by mental illness and a lack of housing.

Oakland also has more people living in vehicles than other Bay Area cities.

In San Francisco, 600 people are living in cars, RVs or vans, according to that county’s 2019 homeless count.

Berkeley has 126 people living in vehicles, according to that city’s data.

Oakland has created “community cabins” — individual sheds for the homeless — and RV safe parking sites to address its homeless crisis. The RV safe parking sites are meant to offload some of the burden that neighborhoods are experiencing, city officials said.

Berkeley is in talks to open another RV safe parking program for 20 vehicles. Oakland, Berkeley and Emeryville are also exploring options to open a regional RV parking site.

The first RV safe parking site opened in East Oakland in June and allows space for about 50 people for up to six months. A second site is in the works to open near the Home Depot at Alameda Avenue where a large encampment sits just outside the hardware chain.

“That is an example of an encampment where the number of RV dwellers outgrows the number of people in tiny homes or tents,” said Elder of the East Oakland Collective.

She and other homeless advocates argue that the city’s towing policy contributes to the problem. When the city opens a new RV site, the vehicles invited to park there are prohibited from re-parking on the street. Towing often impacts people whose RVs are inoperable and aren’t allowed in the site.

“The city is supposed to have a leniency policy — that they will not tow vehicles that people are living in — but we find that is not the case,” Elder said.

The homeless data also show that 78% of Oakland’s unhoused population were living in the city when they lost their home. Most, 54% had been there at least 10 years. Fewer, 15%, lived in Oakland 5 to 9 years, while 11% lived in the city four years or less. Just 3% of homeless Oaklanders are from out of state, and 13% are from another county in California.

Sarah Ravani is a San Francisco Chronicle staff writer. Email: sravani@sfchronicle.com Twitter: @SarRavani