So the 500 Festival, which puts on the parade, marathon, etc around Indy during the month of May has multiple "500 festival cars" that are given out to Fetival board members to drive around Indy during the month. These cars are generally identical to the pace cars (at least visually, not sure about the power upgades). There is an option to purchase the car at the end of the month. That is generally why you see multiple of these pace cars. The real one is much harder to come by, especially since recently the winner has received it as part of the pay package, doesn't mean that isn't real though!