Getting stopped for a traffic violation in a rural county can have serious consequences.

Pretrial detention, or when people are held in jails while they await a hearing, is on the rise in rural counties, even as the jail incarceration rate in big cities is decreasing due to efforts to reduce jail sizes, according to a new study from the Vera Institute of Justice and Safety and Justice Challenge. About 6 out of 10 people inside jails are now held on pretrial detention, while people with actual convictions make up the minority share.

Pretrial detention can have serious consequences for people caught up in the system, such as time lost from their jobs or from their families. The most infamous case may be that of Sandra Bland, a woman who was arrested for assault during a traffic stop and died in jail three days later. People detained in rural jails may wait longer to get a hearing because circuit judges may only appear in district court a few times a month or even each year, the report noted.

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"There are a whole host of personal, family and community harms that come from even two days in jail," said Ram Subramanian, a co-author of the study. "You are at risk of losing your job or losing a couple days of salary, or even whether you can keep your employment."

Pretrial incarceration rates grew the most in the more than 1,900 rural counties in America, reaching a rate of 265 per 100,00 people, compared with 200 for large urban centers.

Critics of pretrial detention call the practice unfair, since it penalizes people who don't have the money to post bail while those with deeper pockets can sidestep the local jail. Ultimately, the practice may cost taxpayers, who are footing the bill for people held in jail while the await a hearing on issues such as traffic violations, driving under the influence or theft.

The causes for the increase in rural pre-trial detention can't be pinned on a single explanation, but includes decisions by local law enforcement about who they opt to arrest and book into jail.

Money can also play a role in rural jail growth. Jail administrators are increasingly jumping into growing demand for renting out their bed space. Overcrowded federal and state prisons, as well as the federal immigration detention system, are turning to local jails for space. Payments can run as high as $169 per person and can "add up to substantial revenue for cash-strapped rural jurisdictions," the report noted.

"A long time ago, this wasn't very common," said Jacob Kang-Brown, a co-author of the study. "In 1978, people only held people in their local counties. Now, 9 out of 10 take per diem payments to hold a jail bed for someone who is in the state prison system, in federal court process" or immigration detention.

The payments can be "an incentive to increase the size of the jails, and compete for jail beds," he added.

Kentucky led the way with the largest share of its jail population held for other authorities, reaching 57 percent in 2014, the study found. Louisiana and Montana jails had the second-highest share of inmates from prisons and other institutions, at 55 percent, the study found.

So who is getting locked up in rural jails? Women and white people, the report found. The number of women in rural county jails jumped 43 percent from 2004 to 2014, while it declined 6 percent in urban jails. The number of white people in rural jails jumped 19 percent during the same time period, while the number declined 15 percent in cities.

"Rural jails started growing dramatically in the 1990s, well before the current opioid epidemic," Kang-Brown said. "We think it may still play a role, the issues predate the opioid crisis."