— Dozens of school buses were running behind schedule Friday afternoon after a number of Wake County school bus drivers refused to get behind the wheel in protest over their pay.

Several drivers told WRAL News that they are tired of living from one paycheck to the next and feel Wake County Public School System administrators haven't lived up to promises to increase their pay.

"When I woke up this morning and tried to pay my bills, I didn't know which one to pay. I have no money to pay my bills," driver Gwen Smith said.

School district spokeswoman Heather Lawing said the dispute was traced to a problem processing pay for bus drivers.

Last month, the Board of Education approved a 3 percent raise for non-classroom school staff, including bus drivers, but the raise wasn't included in some drivers' paychecks Friday, depending on when their hours were entered into the payroll system, Lawing said. The district was cutting new checks or sending money through direct deposit to correct the error, she said.

Bus driver Deanna McDonald said it goes further than the payroll mix up.

"Things are getting worse every year," she said. "I have lost my home. I have to sleep in my car with my kids."

The walkout hit only five transportation districts within the school system, Lawing said, and district officials kept parents updated through Twitter and automated phone calls.

PARENTS: Please be aware we are expecting bus delays this afternoon. Learn more by clicking the link. https://t.co/YQbl9i9plq — Wake County Schools (@WCPSS) October 30, 2015

Some bus routes could be delayed up to an hour, and the Transportation Department was working on the issue, officials said in the automated call. Officials noted in the call that there were "a large number of drivers who are absent this afternoon."

Still, parents weren't pleased with the Friday afternoon surprise.

@WCPSS why did you wait so late to notify parent? I could have made arrangements if I knew earlier!! — wendy moghadam (@wendymog) October 30, 2015

@WCPSS Why did you wait until after dismissal to notify parents about the bus delay? We could have made other arrangements. — Kevin Ashley (@kevashley) October 30, 2015

Lawing said district officials had no warning of the walkout themselves, and they pulled in substitute drivers and put administrators with certified licenses to drive buses behind the wheel to get as many buses on the road as possible.

"We had very good response once we realized this was happening," she said. "That is how we have been able to minimize the delays and minimize the impact on students and families."

About 50 schools were affected by the strike, according to the district website.

Transportation administrators—who were certified—took on routes to cover the driverless busses, according to officials. Drivers who did not take part in the strike also helped finished the routes of missing drivers.