Big series name in auto racing

• __ Series: auto races
• Racing series including the "500"
• Organization that holds a Memorial Day weekend auto race
• It usually begins with the Honda Grand Prix of St. Petersburg
• US motor racing
• Vehicle with an STP logo, maybe
• "500" race-sanctioning group
• Brickyard competitor
• Race-sanctioning biggie

Wikipedia Word definitions in Wikipedia
INDYCAR is an American-based auto racing sanctioning body for Championship auto racing . The organization sanctions four racing series : the premier IndyCar Series (often abbreviated ICS) with its centerpiece Indianapolis 500 , and developmental series ...