A Christmas Eve accident in Pharr left a 6-year-old boy in critical condition and his father arrested for DWI.

The accident happened Monday on the frontage road of U.S. Highway 281 near Nolana Avenue.

Pedro Ibarra, 31, was driving a car with his 6-year-old son when it slammed into the rear of an 18-wheeler.

Pharr police said the boy was trapped inside the car and is listed in critical condition at a hospital.

Ibarra was required to take a blood test after refusing to submit to a breathalyzer. He was arrested on an intoxication assault charge that evening.