NEW YORK — NASCAR star Tony Stewart said he didn’t see a driver walking on a dirt track in upstate New York last year before he struck and killed him, and noted the racer was impaired by marijuana and shouldn’t have been outside his car, according to court papers filed Friday.

Kevin Ward Jr.’s family filed a lawsuit this month that accused Stewart of gross negligence, saying he gunned his engine and put his card into a skid as the 20-year-old Ward walked on the track after a crash at Canandaigua Motorsports Park on Aug. 9, 2014.

Stewart’s attorney, Brian Gwitt, argued in an answer to the Wards’ lawsuit that the racing star didn’t see the crash Ward had been involved in and didn’t realize anyone was on the track.

Gwitt claims Ward’s death was caused by his own decision to exit his car and walk along the track while the race was still going on.