CHELMSFORD, Mass. — Police said that a school bus driver here was arrested on Tuesday for allegedly operating a bus while under the influence of marijuana.

School administrators called the Chelmsford Police Department that morning to investigate after several high school students reported to a teacher that there was a strange odor on the bus they had boarded to go on a field trip. The teacher immediately notified the principal, who boarded the bus with other administrators and could smell the odor of marijuana, according to a police news release. The students were taken off the bus and brought to the cafeteria.

Police officers determined that the bus driver, Ali Mahfuz, 63, was under the influence of marijuana.

Chelmsford Police Chief James Spinney told WMUR that Mahfuz “was extremely unsteady on his feet, [had] bloodshot eyes [and was] unable to communicate properly.”

Mahfuz was charged with operating under the influence of drugs (marijuana); operating negligently as to endanger; and reckless endangerment.

An investigation determined that while Mahfuz had not driven any of the morning bus routes for Chelmsford Public Schools that day, he had just finished a route for Greater Lowell Technical High
School before arriving at Chelmsford High School. Chelmsford police reached out to the Tyngsborough Police Department, where that school is located.

The bus company, North Reading Transportation Inc., is cooperating with the school district and the Chelmsford Police Department on the investigation. A company supervisor was sent to the scene with a new bus and driver to take the students on their field trip. North Reading also suspended Mahfuz pending the investigation’s outcome, according to WMUR.

Tyngsborough Police Chief Richard D. Howe, Tyngsborough Public Schools Superintendent Michael Flanagan, and Greater Lowell Technical High School Superintendent/Director Roger Bourgeois said in a statement that they are working with their partners in Chelmsford on the investigation.

They also said that, based on the information presented, they are confident that the driver was not under the influence of marijuana until after the morning run and drop-off at Greater Lowell Technical High School.

Additionally, Tyngsborough officials clarified in the statement that North Reading Transportation Inc. provides busing services for Greater Lowell Technical High School, but other schools in Tyngsborough are served by a different company. Officials added that they are talking with both school bus companies and that they “expect assurances … that improved safeguards are in the works to prevent potentially dangerous situations like the one that occurred in Chelmsford today.”

Spinney praised the students for speaking up.

“I cannot overstate the role played by the students today in ensuring their safety on the roads,” he said. “They knew something was not right, and they spoke up right away, alerting school administrators. I commend these students for their role in stopping a dangerous situation from unfolding.”

Mahfuz was scheduled to be arraigned on Wednesday in Lowell District Court.