SPARTA, Ky. -- Speedway Motorsports Inc. chairman Bruton Smith said NASCAR needs to implement mandatory cautions, or race stoppages, to bring more excitement to the races.

"Call it what you want, but you've got to have caution flags," Smith said Saturday before the Sprint Cup race at Kentucky Speedway. "That creates excitement. You can't just sit there with nothing happening. It ruins the event. It's damaging to our sport."

Cautions flags and caution laps are down this year in NASCAR. Many races this season have produced long green-flag runs without a lot of passing up front.

The Nationwide Series race at Kentucky on Friday night had a record 113 consecutive green-flag laps. Austin Dillon led 192 of 200 laps and won by 9.8 seconds.

Some fans have criticized the 1.5-mile ovals such as Kentucky, saying those tracks are the problem. Smith vigorously disagrees.