CHARLOTTE, N.C. -- NASCAR has changed the rules on its aerodynamic package for short tracks and road courses because the racing didn't improve at those venues under rules introduced last season.

NASCAR had been fairly adamant the rules package would remain unchanged but reversed course late last season when it was evident the racing clearly had suffered at smaller tracks. The most glaring issue was a ho-hum penultimate race at Phoenix Raceway, which this season will host the championship finale.

A week after the dud in Phoenix, NASCAR president Steve Phelps promised fans the sanctioning body was working on improving the racing at short tracks.

Teams will now use a separate rules package at Bristol, Dover, Martinsville, New Hampshire, Phoenix, Richmond, the Charlotte Roval, Sonoma and Watkins Glen. The changes include a significantly smaller rear spoiler, which shrinks from an 8-inch height to 2.75 inches. The front splitter's overhang will now measure a quarter-inch (down from 2 inches), with approximately 2-inch wings (reduced from 10.5 inches).

There will be alterations to the radiator pan by removing its vertical fencing in an effort to reduce front-end downforce. The dimensions of the pan remain the same.

"Our goal has always been to provide the best possible racing for our fans, regardless of venue," said Steve O'Donnell, NASCAR executive vice president and chief racing development officer. "The 2019 Cup Series race package delivered some of the most exciting races on intermediate and larger tracks that our sport has seen, however we felt we could make improvements to short tracks and road courses.

"We believe we have found the right balance for 2020 that will allow teams to build off their previous knowledge of this package and showcase exciting side-by-side racing at tracks of all sizes."