2 Penske cars knocked out of Daytona 500

Two of the three cars owned by Roger Penske have wrecked in the Daytona 500.

A six-car accident on the seventh lap of Sunday's race collected Penske drivers Brad Keselowski and Sam Hornish Jr. The accident began when Keselowski lost control of his Dodge, potentially because of a tire problem.

The accident also collected Max Papis, Mike Bliss, Boris Said and Regan Smith.

It's the third race this weekend at Daytona International Speedway that has opened with a multi-car accident. The Truck Series race Saturday night had a nine-truck wreck on the first lap, and a later 10-truck accident.

Dale Earnhardt Jr. was involved in a spectacular upside down wreck in the Nationwide race.