NASCAR officials admitted that what they faced in Monday’s rain-delayed Pennsylvania 400 was virtually unprecedented.
The race was delayed to Monday by rain at the track, then underwent a brief delay at the start while track drying continued. After dealing with misty conditions and some rain, it was eventually red-flagged and then shortened 22 laps by fog. The fog rolled across the track and created problems with visibility.
NASCAR first ran laps under caution, then ordered the cars to pit road for a red-flag period but had the drivers remain in them, then had the drivers exit their cars.