Frustration is mounting on the fifth day of the bus strike for Seattle Public Schools. A number of drivers are showing up for work, but some families aren't getting notified that their routes are up and running.

Just after 8:00 a.m. Tuesday morning, a Seattle Public Schools bus pulled up near 10th Avenue E and E Prospect Street. No kids were at the stop to board the bus when it made a stop at the corner. Just two children were visible through the windows.

A witness said the same bus was empty Monday morning despite the kids in the neighborhood who need a ride to school.

"We're just trying to figure it out," said Angie Burgin, a parent of two SPS kids.

Burgin's older son usually rides the bus and is carpooling because of the strike. She had no idea his route was up and running.

"The communication of letting us know there was going to be a strike was good, we were prepared," Burgin said. "But this business of some buses running and some not is kind of confusing."

Kim Mingo, the lead negotiator with First Student, claims more drivers are crossing the picket line every day.

"Today we had over 70 drivers and over 130 routes that were driven by our drivers," Mingo said.

Mingo doesn't know why families aren't being notified. Drivers usually let them know by the afternoon if they're showing up to work next morning.

"In the afternoon we let the district know how many drivers are coming to work the next day," said Mingo. "Then the district determines what routes they want to be driven. Then they have a communication process where they are communicating out to the parents of the students that will be on those routes."

Seattle Public Schools confirms that's the case.

"First Student has been able to add more routes each day, but there is always the risk that a driver assigned to a route may not show up in the morning. That has made family communication difficult," an SPS spokesperson said in a written statement.

According to the district, families should get automated messages in the evening on the continuing strike. A second message later that night if their route is scheduled to run. And a third message in the morning if the route is canceled.

Burgin said she understands and will be waiting for the phone to ring.

"We get phone calls saying they're on strike, and some routes are in process but you'll be notified if your bus is available. But we've got no notification. So we're just relying on each other to take turns carpooling and dropping off kids."

The school district is posting the latest on the bus strike here.