An alleged drunken driver slammed into a construction worker early Saturday — fracturing both of his legs — before swerving out of control and managing to land his vehicle sideways in a ditch, cops said.

Keith Hayes, 28, was heading north on Hylan Boulevard in his Nissan Altima around 12:40 a.m. when he suddenly veered into a construction zone, ramming into a 37-year-old worker, according to police.

Hayes’ car then flipped into a trench in the street.

The injured worker was taken to Staten Island University Hospital North in critical but stable condition.

Police sources said Hayes blew 0.163 on a Breathalyzer test, a blood alcohol content level nearly twice the legal limit for driving. Hayes was arrested and charged with vehicular assault, driving while intoxicated and reckless driving.