The buses were inspected and five of them were removed from service for various infractions including brake issues, exhaust issues and a problem with the emergency exit, DMV officials said.
But it did not appear that any of the violations posed an eminent danger to students, officials said.
Peter Agostini, president of the bus company, said he welcomed the spot inspections. NBT, he said, has more than 200 buses and all of them are regularly maintained and inspected.
Four of seven buses inspected in New Haven and one of three buses inspected in Bridgeport were also taken out of service for repairs, according to the DMV. Those buses are owned by First Student Bus Company.