Los Angeles County residents are growing so pessimistic about the future quality of life that one in three said they plan to leave the county in the next five years, according to a survey released Wednesday by the Public Policy Institute of California.

That level of pessimism is double the percentage of just two years ago when 17 percent felt that way. In the city of Los Angeles specifically, 35 percent of residents surveyed said they planned to leave within five years.

“More L.A. city residents say they plan to leave the county than voted in last week’s mayoral race,” said PPIC survey director Mark Baldassare, referring to the low 26 percent turnout in the city’s primary election. “They plan to vote with their feet.”

Traffic congestion, lack of affordable housing and the poor quality of public schools were the major reasons cited for the gloomy outlook. Nearly three-fourths of the 2,000 residents surveyed said traffic congestion was a major problem, while nearly two-thirds cited lack of affordable housing.

The survey also found support slipping for new or higher taxes to address the problems, with only 52 percent of likely voters saying they would support a half-cent sales tax hike to hire more police and firefighters, well short of the needed two-thirds majority.

Tax hikes to fund local schools or transportation projects fared even worse in the survey, failing even to garner majority support.

What’s more, only 36 percent of county residents gave their local mayor and city council excellent or good ratings, while a mere one in five give high marks to the county Board of Supervisors.

Given the problems, 37 percent of residents said they believed the county would be a worse place to live in 20 years, while only 24 percent said it would be better.