DAYTONA BEACH, Fla. (AP) — NASCAR is clearly defining penalties for teams caught manipulating side skirts on cars.

Anyone who makes unapproved adjustments under caution will be forced to return to pit road for repairs. That car will then restart at the back of the field and have to serve a pass-thru penalty under a green flag.

Should the unapproved adjustment be made during a green-flag stop, the team would be forced back to the pits. Any crew member caught making unapproved adjustments will receive a warning, but the penalty could increase for habitual offenders.

Teams began flaring side skirts last season, and although many believed it was a rules violation, NASCAR took no action. It led to many teams feeling as if they had to do it to keep up with others.

The rules bulletin issued Thursday also defined qualifying procedures. NASCAR will enforce pit-road speed and proper blending onto the track.

NASCAR also will penalize any driver impeding a competitor during qualifying, and their lap could be disallowed.