LOUISVILLE, Ky. (WDRB) -- Louisville is about to have one of the largest fleets of electric buses in the nation.

TARC announced Monday it's adding six of the zero-emission vehicles, bringing its total to 15.

That will make it second biggest fleet in the nation, and the largest east of the Mississippi.

The buses will operate along the Fourth Street corridor, between downtown and Iroquois Park, and will stop at some of Louisville's biggest attractions.

"It's one of the most popular routes in the system, averaging about 4,400 passenger trips on weekdays," said Barry Barker, executive director of TARC. "That's out of a total of 50,000 trips. So, this one route accounts for about 8 or 9 percent of our ridership."

The price tag for the six buses is $4.65 million, most of which was paid for with federal grants.

It's estimated they'll save TARC about 60,000 gallons of fuel each year.

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