SPARTA, Ky. (AP) -- Gov. Steve Beshear has toured the Kentucky Motor Speedway to view new infrastructure improvements designed to ease traffic problems that marred the track's debut race of NASCAR's top series last year.

The state contracted $3.7 million for road improvements to expand Kentucky 35 and Interstate 71, and Speedway general manager Mark Simendinger estimates the track has spent between $8 and $10 million focused on parking an additional 15,000 to 20,000 vehicles. The track's signature event, the Quaker State 400, is set for June 30.

Traffic backed up as much as 15 miles last year after nearby parking filled hours before the race. Some fans were asked to turn around after the race passed its halfway point to allow those who made it in to leave.