They won't eliminate fuel cars, that would kill their draw since that is their target audience. I expect it would be an additional series to see if anyone watches. That is a similar reason why Indy went hybrid not EV.
Jay Frye of Indy Car
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“Each series has their own identity, their own niche of what they do,” said Frye. “[At] INDYCAR, we certainly have no aspirations of being a fully electric series.
“We're fast, loud and authentic, that type of thing. [The hybrid] is an enhancement to our overall program. This is something that is very relevant in street cars and in passenger cars. We think the hybrid program is the way to go into the future.
“We're very comfortable with where we're at right now. We're very comfortable where we're going to be the next couple, two, three years, and then we'll see what the future looks like beyond that.
“I certainly don't see INDYCAR becoming a full EV series.”