claim: The Challenge XXX: Dirty 30 is a season of the year.
evidence: The fifteenth year of IROC competition took place in 1991 .. IROC. IROC. IROC XV was the second year the Dodge Daytona was used in competition , and continued the format introduced in IROC VIII .. IROC. IROC. Dodge Daytona. Dodge Daytona. IROC VIII. IROC VIII. Race one took place on the Daytona International Speedway , race two took place at Talladega Superspeedway , race three ran at Michigan International Speedway , and the year finished at Watkins Glen International .. Daytona International Speedway. Daytona International Speedway. Talladega Superspeedway. Talladega Superspeedway. Michigan International Speedway. Michigan International Speedway. Watkins Glen International. Watkins Glen International. Rusty Wallace won the series championship , and took home $ 175,000 for his efforts .. Rusty Wallace. Rusty Wallace. The roster of drivers and final points standings were as follows  :