The buses are slated to be built at Proterra’s manufacturing facility in Greenville, S.C. in early 2014, with delivery expected later in the year.

TARC’s current fleet of more than 220 buses and trolleys runs 41 routes in five counties in Kentucky and southern Indiana with 15 million customers annually. The new Proterra buses will replace the agency’s Toonerville II Trolleys, which operate free of charge in downtown Louisville’s business district.

“We’re excited about adding the Proterra buses to our fleet and look forward to the benefits — cleaner air, a quieter ride in a sleek, modern vehicle, and fuel and maintenance cost savings, “ said J. Barry Barker, executive director of TARC. “Proterra’s American-made buses have been tested against stringent industry standards and are in operation by other transit agencies.”

Proterra has recently announced several new sales, with the company’s last three orders to transit systems coming from repeat customers — a major vote of confidence in the company’s technology and the buses’ performance, according to the company.