By John Ellement, Jamie Vaznis and David Abel , Globe Correspondent
A wildcat strike by the union representing Boston Public Schools bus drivers has halted service this morning for tens of thousands of students, officials said.
Only 30 of the school system’s 650 buses are on the road. The buses typically carry about 30,000 students to school. School officials said the strike stemmed from a disagreement between the BPS transportation vendor, Veolia, and the union representing the drivers.
“This action is an unacceptable attempt to shut down our entire school system because the Union is unhappy with efforts to increase safety and improve on-time service,†Interim School Superintendent John McDonough said in a statement.
“By failing to work these drivers are denying children their rides to school and are inconveniencing thousands of families. I want to apologize to all of our families and ask for their patience as we continue to press forward on these needed improvements to safety, on-time performance and parents’ ability to track the location of their child’s school bus,†McDonough said.
“It came as a surprise to us,†said BPS spokesman Brian Ballou.
To help students get to school, the mayor’s office announced this morning that any student with a valid student ID could ride the MBTA system for free. Boston police were checking bus stops and streets throughout the city to help children get to school or directing them to transportation.
Ballou said school officials had heard rumblings about the strike and had placed monitors at bus yards this morning, who learned shortly after 5 a.m. that the strike was underway.
E-mail alerts and automated calls have been sent out to all families with children in the schools in hopes that they can arrange alternative ways to get to school.
The school department is trying to negotiate to get full bus service reinstated by the afternoon when school lets out. School officials expect the strike to continue through the morning, at least.
School spokesman Lee McGuire said the strike actions happened at all four of the system’s bus yards.
He said that one of the bus drivers’ complaints was increased GPS monitoring of where school buses are and new policies from Veolia on how to pick up their keys.
“This is 30,000 families who had to scramble at the last minute this morning to find alternative transportation,†he said.
At the Ohrenberger School in West Roxbury, it was unclear how many children would be attending the elementary school.
“We’re getting a lot of parent dropoffs. That’s all we know,†said one person who declined to identify herself and was answering phones, shortly before the 8:30 a.m. start time.
Another woman, who also declined to give her name, said “some parents don’t even know about†the strike and had been calling, wondering where their school bus was.
The strike also affected Boston charter schools, which use city buses. “We didn’t get one bus today,†said Denise Choukas, an administrator at the Neighborhood House Charter School in Dorchester, which has 400 students, kindergarten through eighth grade.
“A lot of kids got rides in. We’re hoping by the end of the day, [the drivers] will be back to work. Our phone is ringing off the hook.
Along Talbot Avenue, mothers were walking their children to school or the MBTA bus stop. Khadijah White was taking her 5-year-old son Denzell to her job nearby, where his father would pick him up.
His bus is supposed to pick him up at Talbot and Norwell at 7:59 a.m. but is usually late, she said. In fact it came around 8:20 a.m. Monday, forcing her to rely on another parent to drive him to the Russell School on Columbia Road, she said.
White said school officials called and told her that some buses would not be running. She said she went to the bus stop, anyway, until a police officer rode by and hold her the bus drivers were on strike.
The two candidates running for mayor of Boston said they were disgusted by the job action.
“It is shameful for the school bus drivers union to use our children as pawns in a political game,†City Councilor John R. Connolly said. “This is about safety first and foremost, and it is totally unacceptable that our children were put at risk this morning, not to mention the impact on thousands of parents who will miss work. Missing even one day of school is a real problem for our children who face a daunting achievement gap.â€
Rep. Martin J. Walsh said, “Kids and parents must come first. This is wrong. The bus drivers have put our children in harm’s way. This is an illegal action, causing a huge disruption, and I call on the bus drivers to return to work immediately. This is a violation of the contract and cannot be tolerated.â€
Meghan Irons and Matt Carroll of the Globe staff contributed to this report. 
