An Ottawa man faces four charges after allegedly attacking an OC Transpo driver while the bus was in motion on Monday night.

Ottawa police said the 50-year-old man was drunk when he boarded the bus on Waller Street just before 7:30 p.m. He allegedly became "belligerent and aggressive towards the driver," according to police.

The bus swerved across the centre line into the direction of oncoming traffic but the incident did not cause any crashes, police said. The driver was not injured.

Police responded to the incident near the intersection of Preston and Somerset streets and arrested the man. He is expected to appear in court Tuesday to face charges of assault, causing a disturbance, public intoxication and breach of probation.