A Louisiana festival turned into a scary situation when a driver plowed into a crowd during a Lao New Year Parade, leaving at least 15 people injured.

The chaos unfolded Saturday afternoon in New Iberia, where cops say a vehicle slammed into multiple pedestrians near the parade route. Video from the aftermath shows people on the ground, while others rush in to help the injured.

Witnesses describe a horrifying scene ... one attendee says the driver appeared to inch forward at first, revving his engine like he was joining the celebration before suddenly barreling into the crowd.

Authorities say several victims suffered serious injuries. At least 13 people were taken to hospitals, and two had to be airlifted for emergency treatment.

Cops say the driver showed clear signs of impairment at the scene. According to police, he blew a .137 BAC. The driver was arrested and hit with a laundry list of charges, including driving while impaired, 18 counts of first-degree negligent injuring, careless operation and open container.

An investigation is now underway.