AVONDALE, Ariz. — NASCAR is primarily focusing its investigation into the gruesome crash last Saturday in Daytona, Fla., on the construction of a gate along the fence line.

That’s where Kyle Larson’s No. 32 car catapulted into the fence, sending debris into the stands, injuring 28 fans, two critically.

NASCAR senior vice president Steve O’Donnell said the gate is getting extra attention “because of where (the car) hit, the pieces that got through and it being a gate area.’’ While O’Donnell assured the gate was locked and secured, the fact that it’s a moving part draws extra attention.

NASCAR impounded Larson’s wrecked car and it’s been examined the past week in Daytona. Now it will be shipped to NASCAR’s research and development center near Charlotte for additional scrutiny.

O’Donnell said an attempt will be made to reconstruct the car, with the assistance of its builders, to see if that contributed to the accident. But NASCAR is less focused on the car than on the fencing, and how it might be improved in the future, particularly at the superspeedways – Daytona and Talladega, Ala.

At a Saturday news conference at Phoenix International Raceway, O’Donnell said only the two fans originally listed as in critical condition remain hospitalized in Florida. Both are now in stable condition.

O’Donnell was also asked about the tire that flew into the stands. He said while a final determination hasn’t been made, “we think it would be impossible’’ for the tire to have flown over the fence, rather than go through it.

NASCAR is hiring an outside engineering firm to review how fencing might be improved to further guard against debris entering the stands. O’Donnell said it’s too early to conclude whether seating rows should be moved a greater distance from the fence.

More racing news, blogs, photos and more at www.ThatsRacin.com.